Temporarily remove EventPrime integration because of security issues. (#89)

Reviewed-on: #89
Co-authored-by: André Menrath <andre.menrath@posteo.de>
Co-committed-by: André Menrath <andre.menrath@posteo.de>

.distignore

@@ -0,0 +1,24 @@
+.distignore
+.git
+.gitignore
+.wordpress-org
+.wp-env.json
+bin
+CHANGELOG.md
+CODE_OF_CONDUCT.md
+composer.json
+composer.lock
+docker-compose.yml
+Dockerfile
+docs
+FEDERATION.md
+Gruntfile.js
+node_modules
+package.json
+package-lock.json
+phpcs.xml
+phpunit.xml
+README.md
+src
+tests
+vendor

.forgejo/workflows/phpcs.yml

@@ -0,0 +1,50 @@
+name: PHP Code Checker
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  phpcs:
+    runs-on: ubuntu-latest
+    services:
+      mysql:
+        image: mariadb
+        env:
+          MYSQL_ROOT_PASSWORD: root
+    strategy:
+      matrix:
+        php-versions: ['8.1']
+    name: PHP Code Checker
+    env:
+      extensions: mysql
+      key: cache-v1
+    steps:
+      - name: Checkout
+        uses: https://code.forgejo.org/actions/checkout@v4
+
+      - name: Cache Composer
+        id: cache-composer
+        uses: https://code.forgejo.org/actions/cache@v4
+        with:
+          path: |
+            ./vendor/
+          key: cache-composer-phpcs-1
+
+      - name: Setup PHP
+        uses: https://github.com/shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-versions }}
+          coverage: none
+          tools: composer
+        env:
+          runner: self-hosted
+
+      - name: Install Composer dependencies for PHP
+        if: steps.cache-composer.outputs.cache-hit != 'true'
+        uses: ramsey/composer-install@v3
+
+      - name: Run PHP_CodeSniffer
+        run: ./vendor/bin/phpcs

.forgejo/workflows/phpunit.yml

@@ -0,0 +1,121 @@
+name: PHPUnit
+
+on:
+  push:
+    branches:
+      - main
+      - improve_tests
+  pull_request:
+
+env:
+  WP_TESTS_DIR: /workspace/wordpress-test-lib
+  WP_CORE_DIR: /workspace/wordpress
+
+jobs:
+  phpunit:
+    runs-on: ubuntu-latest
+    services:
+      mysql:
+        image: mariadb
+        env:
+          MYSQL_ROOT_PASSWORD: root
+    strategy:
+      matrix:
+        php-version: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
+        wordpress-version: ['6.7']
+    name: PHPUnit – PHP ${{ matrix.php-version }}
+    env:
+      extensions: mysql
+      key: cache-v1
+    steps:
+      - name: Checkout
+        uses: https://code.forgejo.org/actions/checkout@v4
+
+      - name: Cache WordPress Setup
+        id: cache-wordpress
+        uses: https://code.forgejo.org/actions/cache@v4
+        with:
+          path: |
+            ${{ env.WP_CORE_DIR }}
+            ${{ env.WP_TESTS_DIR }}
+          key: cache-wordpress-67-4
+
+      - name: Cache Composer
+        id: cache-composer-phpunit
+        uses: https://code.forgejo.org/actions/cache@v4
+        with:
+          path: |
+            ./vendor/
+          key: cache-composer-phpunit-2
+
+      - name: Setup PHP
+        uses: https://github.com/shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          coverage: none
+          tools: composer
+        env:
+          runner: self-hosted
+
+      - name: Install PHPUnit and PHPUnit-Polyfills
+        if: steps.cache-composer-phpunit.outputs.cache-hit != 'true'
+        run: composer require --dev yoast/phpunit-polyfills:"^3.0"
+
+      - name: Install and cache mysqladmin needed to initialize the test database
+        uses: https://github.com/awalsh128/cache-apt-pkgs-action@latest
+        with:
+          packages: mysql-client
+          version: 1.0
+
+      - name: Setup Test Environment
+        if: steps.cache-wordpress.outputs.cache-hit != 'true'
+        run: bash bin/install-wp-tests.sh wordpress_test root root 127.0.0.1 ${{ matrix.wordpress-version }} false false false false
+
+      - name: Initialize WordPress test database
+        if: steps.cache-wordpress.outputs.cache-hit != 'false'
+        run: bash bin/install-wp-tests.sh wordpress_test root root 127.0.0.1 ${{ matrix.wordpress-version }} false true true true
+
+      - name: Run General Tests
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=event_bridge_for_activitypub
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for The Events Calendar
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=the_events_calendar
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for VS Event List
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=vs_event_list
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for GatherPress
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=gatherpress
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for Events Manager
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=events_manager
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for WP Event Manager
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=wp_event_manager
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for Eventin (WP Event Solution)
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=eventin
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for Modern Events Calendar Lite
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=modern_events_calendar_lite
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for Event Organiser
+        run: cd /workspace/Event-Federation/wordpress-event-bridge-for-activitypub/ && ./vendor/bin/phpunit --filter=event_organiser
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}

.forgejo/workflows/release.yml

@@ -0,0 +1,16 @@
+on:
+  push:
+    tags: 'v*'
+
+jobs:
+  upload-release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: https://code.forgejo.org/actions/checkout@v4
+
+      - uses: https://code.forgejo.org/actions/forgejo-release@v2
+        with:
+          direction: upload
+          url: https://code.event-federation.eu
+          release-notes: ${{ TAG }}
+          token: ${{ secrets.GITHUB_TOKEN }}

.gitattributes

@@ -0,0 +1,23 @@
+.distignore  export-ignore
+.forgejo  export-ignore
+.gitattributes  export-ignore
+.gitignore export-ignore
+.wp-env.json  export-ignore
+bin  export-ignore
+CODE_OF_CONDUCT.md  export-ignore
+composer.json  export-ignore
+composer.lock  export-ignore
+docker-compose.yml  export-ignore
+Dockerfile  export-ignore
+docs  export-ignore
+FEDERATION.md  export-ignore
+Gruntfile.js  export-ignore
+node_modules  export-ignore
+package.json  export-ignore
+package-lock.json  export-ignore
+phpcs.xml  export-ignore
+phpunit.xml  export-ignore
+README.md  export-ignore
+src  export-ignore
+tests  export-ignore
+vendor  export-ignore

.gitignore

@@ -1,2 +1,5 @@
-vendor
+vendor/
 composer.lock
+.phpunit.result.cache
+node_modules/
+package-lock.json

CHANGELOG.md

@@ -0,0 +1,11 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.3.3] - 2024-12-19
+
+* Initial release on WordPress.org
+

CODE_OF_CONDUCT.md

@@ -0,0 +1,126 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our
+community a harassment-free experience for everyone, regardless of age, body
+size, visible or invisible disability, ethnicity, sex characteristics, gender
+identity and expression, level of experience, education, socio-economic status,
+nationality, personal appearance, race, caste, color, religion, or sexual
+identity and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming,
+diverse, inclusive, and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment for our
+community include:
+
+* Demonstrating empathy and kindness toward other people
+* Being respectful of differing opinions, viewpoints, and experiences
+* Giving and gracefully accepting constructive feedback
+* Accepting responsibility and apologizing to those affected by our mistakes,
+  and learning from the experience
+* Focusing on what is best not just for us as individuals, but for the overall
+  community
+
+Examples of unacceptable behavior include:
+
+* The use of sexualized language or imagery, and sexual attention or advances of
+  any kind
+* Trolling, insulting or derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or email address,
+  without their explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Enforcement Responsibilities
+
+Community leaders are responsible for clarifying and enforcing our standards of
+acceptable behavior and will take appropriate and fair corrective action in
+response to any behavior that they deem inappropriate, threatening, offensive,
+or harmful.
+
+Community leaders have the right and responsibility to remove, edit, or reject
+comments, commits, code, wiki edits, issues, and other contributions that are
+not aligned to this Code of Conduct, and will communicate reasons for moderation
+decisions when appropriate.
+
+## Scope
+
+This Code of Conduct applies within all community spaces, and also applies when
+an individual is officially representing the community in public spaces.
+Examples of representing our community include using an official email address,
+posting via an official social media account, or acting as an appointed
+representative at an online or offline event.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported to the community leaders responsible for enforcement via email to
+simon@fdpl.io. All complaints will be reviewed and investigated fairly
+and as soon as personal time and energy of community leaders permits.
+
+All community leaders are obligated to respect the privacy and security of the
+reporter of any incident.
+
+## Enforcement Guidelines
+
+Community leaders will follow these Community Impact Guidelines in determining
+the consequences for any action they deem in violation of this Code of Conduct:
+
+### 1. Correction
+
+**Community Impact**: Use of inappropriate language or other behavior deemed
+unprofessional or unwelcome in the community.
+
+**Consequence**: A private, written warning from community leaders, providing
+clarity around the nature of the violation and an explanation of why the
+behavior was inappropriate. A public apology may be requested.
+
+### 2. Warning
+
+**Community Impact**: A violation through a single incident or series of
+actions.
+
+**Consequence**: A warning with consequences for continued behavior. No
+interaction with the people involved, including unsolicited interaction with
+those enforcing the Code of Conduct, for a specified period of time. This
+includes avoiding interactions in community spaces as well as external channels
+like social media. Violating these terms may lead to a temporary or permanent
+ban.
+
+### 3. Temporary Ban
+
+**Community Impact**: A serious violation of community standards, including
+sustained inappropriate behavior.
+
+**Consequence**: A temporary ban from any sort of interaction or public
+communication with the community for a specified period of time. No public or
+private interaction with the people involved, including unsolicited interaction
+with those enforcing the Code of Conduct, is allowed during this period.
+Violating these terms may lead to a permanent ban.
+
+### 4. Permanent Ban
+
+**Community Impact**: Demonstrating a pattern of violation of community
+standards, including sustained inappropriate behavior, harassment of an
+individual, or aggression toward or disparagement of classes of individuals.
+
+**Consequence**: A permanent ban from any sort of public interaction within the
+community.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant](https://www.contributor-covenant.org),
+version 2.1, available at
+[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html](https://www.contributor-covenant.org/version/2/1/code_of_conduct.html).
+
+Community Impact Guidelines were inspired by
+[Mozilla's code of conduct enforcement ladder](https://github.com/mozilla/diversity).
+
+For answers to common questions about this code of conduct, see the FAQ at
+[https://www.contributor-covenant.org/faq](https://www.contributor-covenant.org/faq). Translations are available at
+[https://www.contributor-covenant.org/translations](https://www.contributor-covenant.org/translations).

Dockerfile

@@ -0,0 +1,43 @@
+FROM php:8.1.29-alpine
+
+RUN mkdir /app
+
+WORKDIR /app
+
+# Install Git, NPM & needed libraries
+RUN apk update \
+    && apk add bash git nodejs npm gettext subversion mysql mysql-client zip \
+    && rm -f /var/cache/apk/*
+
+RUN docker-php-ext-install mysqli
+
+# Install Xdebug
+RUN apk add --no-cache $PHPIZE_DEPS \
+    && apk add --update linux-headers \
+    && pecl install xdebug \
+    && docker-php-ext-enable xdebug \
+    && apk del --purge $PHPIZE_DEPS \
+    && echo "xdebug.start_with_request=yes" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini \
+    && echo "xdebug.client_host=host.docker.internal" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini \
+    && echo "xdebug.mode=debug" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini \
+    && echo "xdebug.idekey=VSCODE" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
+
+# Install Composer
+RUN EXPECTED_CHECKSUM=$(curl -s https://composer.github.io/installer.sig) \
+    && curl https://getcomposer.org/installer -o composer-setup.php \
+    && ACTUAL_CHECKSUM="$(php -r "echo hash_file('sha384', 'composer-setup.php');")" \
+    && if [ "$EXPECTED_CHECKSUM" != "$ACTUAL_CHECKSUM" ]; then >&2 echo 'ERROR: Invalid installer checksum'; rm composer-setup.php; exit 1; fi \
+    && php composer-setup.php --quiet \
+    && php -r "unlink('composer-setup.php');" \
+    && mv composer.phar /usr/local/bin/composer
+
+RUN curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar && \
+    chmod +x wp-cli.phar && \
+    mv wp-cli.phar /usr/local/bin/wp
+
+COPY composer.json composer.lock /app/
+RUN composer install --no-scripts --no-autoloader
+RUN composer global require yoast/phpunit-polyfills:"^3.0" --dev
+ENV PATH="/root/.composer/vendor/bin:${PATH}"
+
+RUN chmod +x -R ./

Gruntfile.js

@@ -0,0 +1,59 @@
+module.exports = function (grunt) {
+	// Project configuration.
+	grunt.initConfig(
+		{
+			checktextdomain: {
+				options:{
+					text_domain: 'event-bridge-for-activitypub',
+					keywords: [
+					'__:1,2d',
+					'_e:1,2d',
+					'_x:1,2c,3d',
+					'esc_html__:1,2d',
+					'esc_html_e:1,2d',
+					'esc_html_x:1,2c,3d',
+					'esc_attr__:1,2d',
+					'esc_attr_e:1,2d',
+					'esc_attr_x:1,2c,3d',
+					'_ex:1,2c,3d',
+					'_n:1,2,4d',
+					'_nx:1,2,4c,5d',
+					'_n_noop:1,2,3d',
+					'_nx_noop:1,2,3c,4d'
+					]
+				},
+				files: {
+					src:  [
+					'**/*.php',         // Include all files
+					'!sass/**',         // Exclude sass/
+					'!node_modules/**', // Exclude node_modules/
+					'!tests/**',        // Exclude tests/
+					'!vendor/**',       // Exclude vendor/
+					'!build/**',        // Exclude build/
+					'!static/**',       // Exclude static resources
+					],
+					expand: true
+				}
+			},
+
+			wp_readme_to_markdown: {
+				target: {
+					files: {
+						'README.md': 'readme.txt'
+					},
+				},
+				options: {
+					pre_convert: function ( readme ) {
+						return readme.replace( /\*\*Note\*\*:/g, "> [!NOTE]\n>" );
+					}
+				}
+			}
+		}
+	);
+
+	grunt.loadNpmTasks( 'grunt-wp-readme-to-markdown' );
+	grunt.loadNpmTasks( 'grunt-checktextdomain' );
+
+	// Default task(s).
+	grunt.registerTask( 'default', ['wp_readme_to_markdown', 'checktextdomain'] );
+};

README.md

@@ -1,26 +1,108 @@
-This is a WordPress plugin improves the Fediverse integration of Events via the [WordPress ActivityPub plugin](https://wordpress.org/plugins/activitypub/).
+# Event Bridge for ActivityPub #
+**Contributors:** [andremenrath](https://profiles.wordpress.org/andremenrath/)  
+**Tags:** events, fediverse, activitypub, calendar  
+**Requires at least:** 6.5  
+**Tested up to:** 6.7  
+**Stable tag:** 0.3.3  
+**Requires PHP:** 7.4  
+**License:** AGPL-3.0-or-later  
+**License URI:** https://www.gnu.org/licenses/agpl-3.0.html  
+Integrating popular event plugins with the ActivityPub plugin.
 
-> **_NOTE:_** This is still pre-alpha. It is not more than a skeleton/playground. Things change rapidly. Please contact us, instead of trying it out yourself at this time.
+![Federate your Events, Expand your Reach!](.wordpress-org/banner-1544x500.jpg)
 
-For more information checkout our website https://event-federation.eu/. You can follow updates via [RSS](https://event-federation.eu/feed/) or ActivityPub: [@blog@event-federation.eu](https://event-federation.eu/blog/).
+## Description ##
 
-## Goals
-* Proper ActivityPub (JSON-LD) representation of events within WordPress
-* Improving the setup and configuration workflow of ActivityPub
-* Researching/Implementing federated RSVP/attendee management
+Make your events more discoverable, expand your reach effortlessly while being independent of other (commercial) platforms, and be a part of the growing decentralized web (the Fediverse).
+With the Event Bridge for ActivityPub Plugin for WordPress, your events can be automatically followed, aggregated and displayed across decentralized platforms like [Mastodon](https://joinmastodon.org) or [Gancio](https://gancio.org), without any extra work.
+Forget the hassle of managing multiple social media accounts just to keep your audience informed.
 
-## Supported Event Plugins
+This plugin is not an event managing plugin but an add-on to popular event plugins. It extends their functionality to fully support the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/).
+With the ActivityPub plugin people can follow your website directly and engage with your events just as they would on social media: liking, boosting and even commenting if you enable it.
+You retain full ownership of your content. By integrating into your existing setup, it ensures no extra work is needed while enhancing your events' visibility across the web.
 
-### Events plugin that will be supported at first:
+### How It Works ###
+
+With the Event Bridge for ActivityPub WordPress plugin, sharing your events is effortless and automatic!
+Once you create an event on your WordPress site, it is seamlessly shared across the decentralized web using the ActivityPub protocol.
+
+<p align="center">
+    <img src="./.wordpress-org/event-activitypub-publishing.gif" alt="Logo" width="300"/>
+</p>
+
+Your events can be automatically delivered to platforms that fully support events, such as [Mobilizon](https://joinmobilizon.org/), [Gancio](https://gancio.org), [Friendica](https://friendi.ca), [Hubzilla](https://hubzilla.org), and [Pleroma](https://pleroma.social/).
+These platforms create public event calendars by pulling in events from various sources, including your website. Any updates you make to your events are synced across these platforms—so you only need to manage your events on your own site, with no extra work required.
+
+<p align="center">
+    <img src="./.wordpress-org/decentralized-event-calenders.gif" alt="Logo" width="250"/>
+</p>
+
+Even platforms that don't yet fully support events, like [Mastodon](https://joinmastodon.org), will still receive a detailed, well-composed summary of your event.
+The Event Federation plugin ensures that users from those platforms are provided with all important information about an event.
+
+### Features for Your WordPress Events and the Fediverse ###
+
+**ActivityPub-Enabled Event Sharing:** Your WordPress events are now compatible with the Fediverse, using the ActivityStreams format. This means your events can be easily discovered and followed by users on platforms like Mastodon and other ActivityPub-compatible services.
+
+**Automatic Event Summaries:** When your event is shared on the Fediverse, platforms like Mastodon that don't fully support events will display a brief HTML summary of key details — such as the event's title, start time, and location. This ensures that even if someone can't view the full event on their platform, they still get the important info at a glance, with a link to your WordPress event page. Advanced users can create custom summaries via a set of shortcodes.
+
+**Improved Event Discoverability:** Your custom event categories are mapped to a set of default categories used in the Fediverse, helping your events reach a wider audience. This improves the chances that users searching for similar events on other platforms will find yours.
+
+**Event Reminders for Your Followers:** Often, events are planned well in advance. To keep your followers informed right in time, you can set up reminders that are supposed to trigger the events showing up in their timelines right before the event starts. At the moment this reminder is implemented as a self-boost of your original event post. While this feature may behave differently across various platforms, we are working on a more robust solution that will let you schedule dedicated reminder notes that appear in all followers' timelines.
+
+## Installation ##
+
+This plugin depends on the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/). Additionally, you need to use one of the supported event Plugins.
+
+### Supported Event Plugins ###
 
 * [The Events Calendar](https://de.wordpress.org/plugins/the-events-calendar/)
 * [VS Event List](https://de.wordpress.org/plugins/very-simple-event-list/)
 * [Events Manager](https://de.wordpress.org/plugins/events-manager/)
-* [GatherPress](https://github.com/GatherPress/gatherpress)
+* [WP Event Manager](https://de.wordpress.org/plugins/wp-event-manager/)
+* [Eventin](https://de.wordpress.org/plugins/wp-event-solution/)
+* [Modern Events Calendar Lite](https://webnus.net/modern-events-calendar/)
+* [GatherPress](https://gatherpress.org/)
+* [Event Organiser](https://wordpress.org/plugins/event-organiser/)
+
+## Configuration ##
+
+If you're new to the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/), it’s recommended to spend a few minutes reading through its documentation to familiarize yourself with its setup and functionality.
+
+## Frequently Asked Questions ##
+
+### Do I need to install another event plugin to use the Event Federation Plugin? ###
+
+Yes, this plugin works as an add-on and requires both the ActivityPub plugin and a supported event plugin such as The Events Calendar, VS Event List, or Events Manager to manage your events. It just fills the missing gap between event plugins and the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/).
+
+### What platforms can follow my events? ###
+
+Your events can be followed on platforms that support ActivityPub like [Mobilizon](https://joinmobilizon.org/), [Gancio](https://gancio.org), [Friendica](https://friendi.ca), [Hubzilla](https://hubzilla.org), and [Pleroma](https://pleroma.social/). Even other applications like [Mastodon](https://joinmastodon.org), which don't fully support events yet, will display all important information about the events.
+
+### How much extra work is required to maintain my events across the decentralized Web? ###
+
+None! Once the plugin is set up, your events are automatically sent to all connected platforms or account that follow you (your Website). Any updates you make to your events are synced without additional effort.
+
+### Can I still use social media to promote my events? ###
+
+Yes, you can still use traditional social media if you wish. However, this plugin helps reduce reliance on commercial platforms by connecting your events to the decentralized Fediverse.
+
+### Will this plugin work if I don't use the ActivityPub plugin? ###
+
+No, the Event Federation Plugin depends on the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/) to deliver your events across decentralized platforms, so it's essential to have it installed and configured.
+
+### My event plugin is not supported, what can I do? ###
+
+If you know about coding have a look at the documentation of how to add your plugin or open an [issue](https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub/issues), if we can spare some free hours we might add it.
+
+### What if I experience problems? ###
+
+We're always interested in your feedback. Feel free to reach out to us via [E-Mail](https://event-federation.eu/contact/) or create an [issue](https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub/issues).
+
+## Changelog ##
+
+### [0.3.3] 2024-12-19 ###
+
+* Initial release on https://wordpress.org/
 
-### Later:
-- [All in One Events Calendar](https://de.wordpress.org/plugins/all-in-one-event-calendar/)
-- TBA 
 
-### Your event plugin:
-- [**Contact us**](https://event-federation.eu/contact/), if you want to see your event plugin on the list.

activitypub-event-extensions.php

@@ -1,113 +0,0 @@
-<?php
-/**
- * Plugin Name: ActivityPub Event Extensions
- * Description: Custom ActivityPub Transformers and Integretions for common Event Plugins
- * Plugin URI:  https://event-federation.eu/
- * Version:     1.0.0
- * Author:      André Menrath
- * Author URI:  https://graz.social/@linos
- * Text Domain: activitypub-event-extensions
- * License:     AGPL-3.0-or-later
- *
- * ActivityPub tested up to: 2.2.0
- * 
- * @package activitypub-event-extensions
- * @license AGPL-3.0-or-later
- */
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
-/**
- * Add the custom transformers for the events of several WordPress event plugins.
- */
-add_filter(
-	'activitypub_transformer',
-	function( $transformer, $wp_object, $object_class ) {
-		if ( 'WP_Post' != $object_class ) {
-			return $transformer;
-		}
-
-		/**
-		 * VS Event List
-		 * @see https://wordpress.org/plugins/very-simple-event-list/
-		 */
-		if ( class_exists( 'vsel_widget' ) && $wp_object->post_type === 'event' ) {
-			require_once __DIR__ . '/includes/activitypub/transformer/class-vs-event.php';
-			return new \VS_Event( $wp_object );
-		}
-
-		/**
-		 * Events manager
-		 * @see https://wordpress.org/plugins/events-manager/
-		 */
-		if ( class_exists( 'EM_Events' ) && $wp_object->post_type === 'event' ) {
-			require_once __DIR__ . '/includes/activitypub/transformer/class-events-manager.php';
-			return new \Events_Manager( $wp_object );
-		}
-
-		/**
-		 * Events manager
-		 * @see https://wordpress.org/plugins/events-manager/
-		 */
-		if ( class_exists( 'GatherPress\Core\Event' ) && $wp_object->post_type === 'gp_event' ) {
-			require_once __DIR__ . '/includes/activitypub/transformer/class-gatherpress.php';
-			return new \GatherPress( $wp_object );
-		}
-
-		// Return the default transformer.
-
-		return $transformer;
-	},
-	10,
-	3
-);
-
-
-/**
- * Activate the plugin.
- */
-function activitypub_event_extensions_activate() { 
-	// Don't allow plugin activation, when the ActivityPub plugin is not activated yet.
-	if( ! class_exists( 'ActivtiyPub' ) ) {
-        deactivate_plugins( plugin_basename( __FILE__ ) );
-        wp_die( __( 'Please install and Activate ActivityPub.', 'activitypub-event-extensions' ), 'Plugin dependency check', array( 'back_link' => true ) );
-    }
-}
-
-register_activation_hook( __FILE__, 'activitypub_event_extensions_activate' );
-
-
-// TODO:
-// require_once __DIR__ . '/admin/class-admin-notices.php';
-// new \Admin_Notices();
-
-/**
- * Add a filter for http_request_host_is_external
- *
- * TODO: Remove this.
- *
- * @todo This filter is temporary code needed to do local testing.
- */
-add_filter( 'http_request_host_is_external', 'custom_http_request_host_is_external', 10, 3 );
-
-// Your custom callback function
-function custom_http_request_host_is_external( $is_external, $host, $url ) {
-	$is_external = true;
-
-	return $is_external;
-}
-
-/**
- * Don't verify ssl certs for testing.
- *
- * TODO: Remove this.
- *
- * @todo This filter is temporary code needed to do local testing.
- */
-add_filter( 'https_ssl_verify', 'dont_verify_local_dev_https', 10, 3 );
-
-function dont_verify_local_dev_https( $url ) {
-	return false;
-}

admin/class-admin-notices.php

@@ -1,115 +0,0 @@
-<?php
-/**
- * Admin Notices for guiding to proper configuration of ActivityPub with event plugins.
- *
- * @package activity-event-transformers
- * @license AGPL-3.0-or-later
- */
-
-// TODO: Modularize after we know what we want.
-class Admin_Notices {
-	const VSEL_PLUGIN_FILE = 'very-simple-event-list/vsel.php';
-	const VSEL_POST_TYPE = 'event';
-	const EVENTS_MANAGER_PLUGIN_FILE = 'events-manager/events-manager.php';
-	const EVENTS_MANAGER_POTS_TYPE = 'event';
-    const TRIBE_POST_TYPE = 'tribe_events';
-    const TRIBE_PLUGIN_FILE = 'the-events-calendar/the-events-calendar.php';
-	const ACTIVITYPUB_PLUGIN_FILE = 'activitypub/activitypub.php';
-
-	/**
-	 * Add actions and filters.
-	 */
-	public function __construct() {
-		add_action( 'admin_init', array( self::class, 'check_for_admin_notices' ) );
-	}
-
-	/**
-	 * Check the conditions for admin notices
-	 *
-	 * These should mainly improve usability.
-	 */
-	public static function check_for_admin_notices() {
-
-		if ( is_admin() && is_plugin_active( self::ACTIVITYPUB_PLUGIN_FILE ) ) {
-			// Check for VSEL
-			if ( is_plugin_active( self::VSEL_PLUGIN_FILE ) && self::post_type_is_not_activitypub_enabled( self::VSEL_POST_TYPE ) ) {
-				add_action( 'admin_notices', array( self::class, 'vsel_admin_notices' ) );
-			}
-            // Check for Events Manager
-			if ( is_plugin_active( self::EVENTS_MANAGER_PLUGIN_FILE ) && self::post_type_is_not_activitypub_enabled( self::EVENTS_MANAGER_POTS_TYPE ) ) {
-				add_action( 'admin_notices', array( self::class, 'events_manager_admin_notices' ) );
-			}
-            // Check for The Events Calendar
-            if ( is_plugin_active( self::TRIBE_PLUGIN_FILE ) && self::post_type_is_not_activitypub_enabled( self::TRIBE_POST_TYPE ) ) {
-				add_action( 'admin_notices', array( self::class, 'the_events_calendar_admin_notices' ) );
-			}
-		}
-	}
-
-	/**
-	 * Check if ActivityPub is enabled for the custom post type of the event plugin.
-	 *
-	 * @param string $post_type The post type of the event plugin.
-	 * @return bool
-	 */
-	private static function post_type_is_not_activitypub_enabled( $post_type ) {
-		return ! in_array( $post_type, get_option( 'activitypub_support_post_types' ) );
-	}
-
-	/**
-	 * Check whether to do any admin notices for VSEL
-	 */
-	public static function vsel_admin_notices() {
-		$is_vsel_edit_page = isset( $_GET['post_type'] ) && $_GET['post_type'] === self::VSEL_POST_TYPE;
-		$is_vsel_settings_page = strpos( $_SERVER['REQUEST_URI'], '/wp-admin/options-general.php?page=vsel' ) !== false;
-		$is_vsel_page = $is_vsel_edit_page || $is_vsel_settings_page;
-		if ( $is_vsel_page ) {
-			self::do_admin_notice_post_type_not_activitypub_enabled( self::VSEL_PLUGIN_FILE );
-		}
-	}
-
-    /**
-	 * Check whether to do any admin notices for Events Manager
-	 */
-	public static function events_manager_admin_notices() {
-		$is_events_manager_page = isset( $_GET['post_type'] ) && $_GET['post_type'] === self::EVENTS_MANAGER_POTS_TYPE;
-		if ( $is_events_manager_page ) {
-			self::do_admin_notice_post_type_not_activitypub_enabled( self::EVENTS_MANAGER_PLUGIN_FILE );
-		}
-	}
-
-    /**
-	 * Check whether to do any admin notices for The Events Calendar
-	 */
-	public static function the_events_calendar_admin_notices() {
-		$is_events_manager_page = isset( $_GET['post_type'] ) && $_GET['post_type'] === self::TRIBE_POST_TYPE;
-		if ( $is_events_manager_page ) {
-			self::do_admin_notice_post_type_not_activitypub_enabled( self::TRIBE_PLUGIN_FILE );
-		}
-	}
-
-	/**
-	 * Print admin notice that the current post type is not enabled in the ActivityPub plugin.
-	 */
-	private static function do_admin_notice_post_type_not_activitypub_enabled( $event_plugin_file ) {
-		$vsel_plugin_data = get_plugin_data( WP_PLUGIN_DIR . '/' . $event_plugin_file );
-		$activitypub_plugin_data = get_plugin_data( WP_PLUGIN_DIR . '/' . self::ACTIVITYPUB_PLUGIN_FILE );
-		$notice = sprintf(
-			_x(
-				'You have installed the %1$s plugin, but the event post type of %2$s is not enabled in the <a href="%3$s">%1$s settings</a>.',
-				'admin notice',
-				'your-text-domain'
-			),
-			$activitypub_plugin_data['Name'],
-			$vsel_plugin_data['Name'],
-			admin_url( 'options-general.php?page=activitypub&tab=settings' )
-		);
-		wp_admin_notice(
-			$notice,
-			array(
-				'type' => 'warning',
-				'dismissible' => true,
-			)
-		);
-	}
-}

assets/css/event-bridge-for-activitypub-admin.css

@@ -0,0 +1,187 @@
+.settings_page_event-bridge-for-activitypub #wpcontent {
+	padding-left: 0;
+}
+
+.event-bridge-for-activitypub-settings-page .box {
+	border: 1px solid #c3c4c7;
+	background-color: #fff;
+	padding: 1em 1.5em;
+	margin-bottom: 1.5em;
+}
+
+.event-bridge-for-activitypub-settings-page .box ul.event-bridge-for-activitypub-list {
+	margin-left: 0.6em;
+}
+
+.event-bridge-for-activitypub-settings-page .box pre {
+	padding: 1rem;
+	min-height: 200px;
+	box-shadow: none;
+	border-radius: 15px;
+	border: 1px solid #dfe0e2;
+	background-color: #f7f7f7;
+}
+
+.event-bridge-for-activitypub-settings {
+	max-width: 800px;
+	margin: 0 auto;
+}
+
+.event-bridge-for-activitypub-settings-header {
+	text-align: center;
+	margin: 0 0 1rem;
+	background: #fff;
+	border-bottom: 1px solid #dcdcde;
+}
+
+.event-bridge-for-activitypub-settings-title-section {
+	display: flex;
+	align-items: center;
+	justify-content: center;
+	clear: both;
+	padding-top: 8px;
+}
+
+.event-bridge-for-activitypub-settings-tabs-wrapper {
+	display: -ms-inline-grid;
+	-ms-grid-columns: auto auto auto auto;
+	vertical-align: top;
+	display: inline-grid;
+	grid-template-columns: auto auto auto auto;
+}
+
+.event-bridge-for-activitypub-settings-tab.active {
+	box-shadow: inset 0 -3px #3582c4;
+	font-weight: 600;
+}
+
+.event-bridge-for-activitypub-settings-tab {
+	display: block;
+	text-decoration: none;
+	color: inherit;
+	padding: .5rem 1rem 1rem;
+	margin: 0 1rem;
+	transition: box-shadow .5s ease-in-out;
+}
+
+.event-bridge-for-activitypub-settings .box h3 {
+	font-size: 1.15em;
+	margin-bottom: 0em;
+}
+
+#event_bridge_for_activitypub_initially_activated {
+	display: hidden;
+}
+
+/* Accordions for admin pages */
+.event-bridge-for-activitypub-settings-accordion {
+	border: 1px solid #c3c4c7;
+}
+
+.event-bridge-for-activitypub-settings-accordion-heading {
+	margin: 0;
+	border-top: 1px solid #c3c4c7;
+	font-size: inherit;
+	line-height: inherit;
+	font-weight: 600;
+	color: inherit;
+}
+
+.event-bridge-for-activitypub-settings-accordion-heading:first-child {
+	border-top: none;
+}
+
+.event-bridge-for-activitypub-settings-accordion-panel {
+	margin: 0;
+	padding: 1em 1.5em;
+	background: #fff;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger {
+	background: #fff;
+	border: 0;
+	color: #2c3338;
+	cursor: pointer;
+	display: flex;
+	font-weight: 400;
+	margin: 0;
+	padding: 1em 3.5em 1em 1.5em;
+	min-height: 46px;
+	position: relative;
+	text-align: left;
+	width: 100%;
+	align-items: center;
+	justify-content: space-between;
+	-webkit-user-select: auto;
+	user-select: auto;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger {
+	color: #2c3338;
+	cursor: pointer;
+	font-weight: 400;
+	text-align: left;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger .title {
+	pointer-events: none;
+	font-weight: 600;
+	flex-grow: 1;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger .icon,
+.event-bridge-for-activitypub-settings-accordion-viewed .icon {
+	border: solid #50575e medium;
+	border-width: 0 2px 2px 0;
+	height: .5rem;
+	pointer-events: none;
+	position: absolute;
+	right: 1.5em;
+	top: 50%;
+	transform: translateY(-70%) rotate(45deg);
+	width: .5rem;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger[aria-expanded="true"] .icon {
+	transform: translateY(-30%) rotate(-135deg);
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger:active,
+.event-bridge-for-activitypub-settings-accordion-trigger:hover {
+	background: #f6f7f7;
+}
+
+.event-bridge-for-activitypub-settings-accordion-trigger:focus {
+	color: #1d2327;
+	border: none;
+	box-shadow: none;
+	outline-offset: -1px;
+	outline: 2px solid #2271b1;
+	background-color: #f6f7f7;
+}
+
+.event-bridge-for-activitypub-settings-inline-icon {
+	width: 1.5em;
+	height: 1.5em;
+	vertical-align: middle;
+	margin: 0 0.3em;
+}
+
+code.event-bridge-for-activitypub-settings-example-url {
+	display: block;
+	background: rgb(28, 29, 33);
+	padding: 8px;
+	margin: 10px 0px 10px 0;
+	border-radius: 7px;
+	color: #d5d5d6;
+	overflow-x: auto;
+	word-break: break-all;
+}
+
+#event_bridge_for_activitypub_summary_type_custom-details {
+	display: none;
+}
+
+#event_bridge_for_activitypub_summary_type_custom-details > details {
+	padding: 0.5em;
+}

assets/img/activitypub.svg

@@ -0,0 +1,288 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:osb="http://www.openswatchbook.org/uri/2009/osb"
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:xlink="http://www.w3.org/1999/xlink"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="130"
+   height="130"
+   viewBox="0 0 34.395832 34.395832"
+   version="1.1"
+   id="svg8"
+   inkscape:version="0.92.1 r15371"
+   sodipodi:docname="ActivityPub-logo-symbol.svg">
+  <title
+     id="title4590">ActivityPub logo</title>
+  <defs
+     id="defs2">
+    <linearGradient
+       id="AP-4-0"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#5e5e5e;stop-opacity:1;"
+         offset="0"
+         id="stop5660" />
+    </linearGradient>
+    <linearGradient
+       id="linearGradient5640"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#000000;stop-opacity:1;"
+         offset="0"
+         id="stop5638" />
+    </linearGradient>
+    <linearGradient
+       id="linearGradient5634"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#000000;stop-opacity:1;"
+         offset="0"
+         id="stop5632" />
+    </linearGradient>
+    <linearGradient
+       id="linearGradient5628"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#000000;stop-opacity:1;"
+         offset="0"
+         id="stop5626" />
+    </linearGradient>
+    <linearGradient
+       id="AP-3-7"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#c678c5;stop-opacity:1;"
+         offset="0"
+         id="stop5498" />
+    </linearGradient>
+    <linearGradient
+       id="AP-2-3"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#6d6d6d;stop-opacity:1;"
+         offset="0"
+         id="stop5230" />
+    </linearGradient>
+    <linearGradient
+       id="AP1-5"
+       osb:paint="solid">
+      <stop
+         style="stop-color:#f1007e;stop-opacity:1;"
+         offset="0"
+         id="stop5212" />
+    </linearGradient>
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP-3-7"
+       id="linearGradient5749"
+       gradientUnits="userSpaceOnUse"
+       x1="3319.292"
+       y1="-1291.2802"
+       x2="3344.3645"
+       y2="-1291.2802" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP1-5"
+       id="linearGradient7297-7"
+       gradientUnits="userSpaceOnUse"
+       x1="3241.6836"
+       y1="-1355.4329"
+       x2="3254.9529"
+       y2="-1355.4329" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP-2-3"
+       id="linearGradient7303-7"
+       gradientUnits="userSpaceOnUse"
+       x1="3225.7603"
+       y1="-1355.4329"
+       x2="3239.0295"
+       y2="-1355.4329" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP1-5"
+       id="linearGradient8308"
+       gradientUnits="userSpaceOnUse"
+       x1="3241.6836"
+       y1="-1355.4329"
+       x2="3254.9529"
+       y2="-1355.4329" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP1-5"
+       id="linearGradient8310"
+       gradientUnits="userSpaceOnUse"
+       x1="3241.6836"
+       y1="-1355.4329"
+       x2="3254.9529"
+       y2="-1355.4329" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP1-5"
+       id="linearGradient8312"
+       gradientUnits="userSpaceOnUse"
+       x1="3241.6836"
+       y1="-1355.4329"
+       x2="3254.9529"
+       y2="-1355.4329" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP-2-3"
+       id="linearGradient8314"
+       gradientUnits="userSpaceOnUse"
+       x1="3225.7603"
+       y1="-1355.4329"
+       x2="3239.0295"
+       y2="-1355.4329"
+       gradientTransform="matrix(3.7000834,0,0,3.7000834,-11935.582,4544.6634)" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#AP-2-3"
+       id="linearGradient5188"
+       gradientUnits="userSpaceOnUse"
+       gradientTransform="matrix(0.42732603,0,0,0.42732603,-1363.3009,454.91899)"
+       x1="3269.126"
+       y1="-1354.6217"
+       x2="3322.1943"
+       y2="-1354.6217" />
+  </defs>
+  <sodipodi:namedview
+     id="base"
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="0.14509804"
+     inkscape:pageopacity="0.0"
+     inkscape:pageshadow="2"
+     inkscape:zoom="0.70710678"
+     inkscape:cx="-195.34129"
+     inkscape:cy="-120.65903"
+     inkscape:document-units="px"
+     inkscape:current-layer="layer1"
+     showgrid="false"
+     inkscape:snap-global="true"
+     showguides="false"
+     inkscape:guide-bbox="true"
+     showborder="true"
+     fit-margin-top="0"
+     fit-margin-left="0"
+     fit-margin-right="0"
+     fit-margin-bottom="0"
+     inkscape:showpageshadow="false"
+     borderlayer="false"
+     units="px">
+    <inkscape:grid
+       type="xygrid"
+       id="grid4572"
+       enabled="false"
+       originx="7.1437514"
+       originy="-404.28382" />
+    <inkscape:grid
+       type="axonomgrid"
+       id="grid4574"
+       units="mm"
+       empspacing="12"
+       originx="7.1437514"
+       originy="-404.28382"
+       enabled="false" />
+    <sodipodi:guide
+       position="3278.981,1256.5057"
+       orientation="0,1"
+       id="guide5059"
+       inkscape:locked="false" />
+    <sodipodi:guide
+       position="3278.981,1238.2495"
+       orientation="0,1"
+       id="guide5061"
+       inkscape:locked="false" />
+  </sodipodi:namedview>
+  <metadata
+     id="metadata5">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title>ActivityPub logo</dc:title>
+        <cc:license
+           rdf:resource="http://creativecommons.org/publicdomain/zero/1.0/" />
+        <dc:date>2017-04-15</dc:date>
+        <dc:creator>
+          <cc:Agent>
+            <dc:title>Robert Martinez</dc:title>
+          </cc:Agent>
+        </dc:creator>
+        <dc:subject>
+          <rdf:Bag>
+            <rdf:li>ActivityPub</rdf:li>
+          </rdf:Bag>
+        </dc:subject>
+      </cc:Work>
+      <cc:License
+         rdf:about="http://creativecommons.org/publicdomain/zero/1.0/">
+        <cc:permits
+           rdf:resource="http://creativecommons.org/ns#Reproduction" />
+        <cc:permits
+           rdf:resource="http://creativecommons.org/ns#Distribution" />
+        <cc:permits
+           rdf:resource="http://creativecommons.org/ns#DerivativeWorks" />
+      </cc:License>
+    </rdf:RDF>
+  </metadata>
+  <g
+     inkscape:label="Layer 1"
+     inkscape:groupmode="layer"
+     id="layer1"
+     style="opacity:1"
+     transform="translate(7.1437516,141.67967)">
+    <path
+       style="fill:#000000;stroke-width:0.26458335"
+       d=""
+       id="path5497"
+       inkscape:connector-curvature="0" />
+    <g
+       id="g5197"
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+      <g
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+         style="fill:url(#linearGradient7297-7);fill-opacity:1"
+         transform="matrix(0.9789804,0,0,0.9789804,-3157.9561,1202.4422)">
+        <g
+           transform="matrix(0.2553682,0,0,0.2553682,2615.9213,-1125.3113)"
+           id="g5080-78"
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+        <path
+           id="path5467-2-0"
+           transform="matrix(0.27026418,0,0,0.27026418,3225.7603,-1228.2597)"
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+           inkscape:connector-curvature="0" />
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+    </g>
+  </g>
+</svg>

assets/img/fediverse.svg

@@ -0,0 +1,17 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="196.52mm" height="196.52mm" viewBox="0 0 196.52 196.52">
+	<path fill="#a730b8" d="M47.9242 72.7966a18.2278 18.2278 0 0 1-7.7959 7.7597l42.7984 42.9653 10.3182-5.2291zm56.4524 56.6704-10.3182 5.2291 21.686 21.7708a18.2278 18.2278 0 0 1 7.7975-7.7608z"/>
+	<path fill="#5496be" d="M129.6645 102.0765l1.7865 11.4272 27.4149-13.8942a18.2278 18.2278 0 0 1-4.9719-9.8124zm-14.0658 7.1282-57.2891 29.0339a18.2278 18.2278 0 0 1 4.9728 9.8133l54.1027-27.4194z"/>
+	<path fill="#ce3d1a" d="M69.5312 91.6539l8.1618 8.1933 29.269-57.1387a18.2278 18.2278 0 0 1-9.787-5.0219zm-7.1897 14.0363-14.0022 27.3353a18.2278 18.2278 0 0 1 9.786 5.0214l12.3775-24.1639z"/>
+	<path fill="#d0188f" d="M39.8906 80.6763a18.2278 18.2278 0 0 1-10.8655 1.7198l8.1762 52.2981a18.2278 18.2278 0 0 1 10.8645-1.7198z"/>
+	<path fill="#5b36e9" d="M63.3259 148.3109a18.2278 18.2278 0 0 1-1.7322 10.8629l52.2893 8.3907a18.2278 18.2278 0 0 1 1.7322-10.8629z"/>
+	<path fill="#30b873" d="M134.9148 146.9182a18.2278 18.2278 0 0 1 9.788 5.0224l24.1345-47.117a18.2278 18.2278 0 0 1-9.7875-5.0229z"/>
+	<path fill="#ebe305" d="M126.1329 33.1603a18.2278 18.2278 0 0 1-7.7975 7.7608l37.3765 37.5207a18.2278 18.2278 0 0 1 7.7969-7.7608z"/>
+	<path fill="#f47601" d="M44.7704 51.6279a18.2278 18.2278 0 0 1 4.9723 9.8123l47.2478-23.9453a18.2278 18.2278 0 0 1-4.9718-9.8113z"/>
+	<path fill="#57c115" d="M118.2491 40.9645a18.2278 18.2278 0 0 1-10.8511 1.8123l4.1853 26.8 11.42 1.8324zm-4.2333 44.1927 9.8955 63.3631a18.2278 18.2278 0 0 1 10.88-1.6278l-9.355-59.9035z"/>
+	<path fill="#dbb210" d="M49.7763 61.6412a18.2278 18.2278 0 0 1-1.694 10.8686l26.8206 4.3077 5.2715-10.2945zm45.9677 7.382-5.272 10.2955 63.3713 10.1777a18.2278 18.2278 0 0 1 1.7606-10.8593z"/>
+	<path fill="#ffca00" d="M93.4385 23.8419a1 1 0 1 0 33.0924 1.8025 1 1 0 1 0-33.0924-1.8025"/>
+	<path fill="#64ff00" d="M155.314 85.957a1 1 0 1 0 33.0923 1.8025 1 1 0 1 0-33.0923-1.8025"/>
+	<path fill="#00a3ff" d="M115.3466 163.9824a1 1 0 1 0 33.0923 1.8025 1 1 0 1 0-33.0923-1.8025"/>
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+	<path fill="#ff0000" d="M15.2298 63.4781a1 1 0 1 0 33.0923 1.8025 1 1 0 1 0-33.0923-1.8025"/>
+</svg>

assets/img/mastodon.svg

@@ -0,0 +1,10 @@
+<svg width="75" height="79" viewBox="0 0 75 79" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M73.8393 17.4898C72.6973 9.00165 65.2994 2.31235 56.5296 1.01614C55.05 0.797115 49.4441 0 36.4582 0H36.3612C23.3717 0 20.585 0.797115 19.1054 1.01614C10.5798 2.27644 2.79399 8.28712 0.904997 16.8758C-0.00358524 21.1056 -0.100549 25.7949 0.0682394 30.0965C0.308852 36.2651 0.355538 42.423 0.91577 48.5665C1.30307 52.6474 1.97872 56.6957 2.93763 60.6812C4.73325 68.042 12.0019 74.1676 19.1233 76.6666C26.7478 79.2728 34.9474 79.7055 42.8039 77.9162C43.6682 77.7151 44.5217 77.4817 45.3645 77.216C47.275 76.6092 49.5123 75.9305 51.1571 74.7385C51.1797 74.7217 51.1982 74.7001 51.2112 74.6753C51.2243 74.6504 51.2316 74.6229 51.2325 74.5948V68.6416C51.2321 68.6154 51.2259 68.5896 51.2142 68.5661C51.2025 68.5426 51.1858 68.522 51.1651 68.5058C51.1444 68.4896 51.1204 68.4783 51.0948 68.4726C51.0692 68.4669 51.0426 68.467 51.0171 68.4729C45.9835 69.675 40.8254 70.2777 35.6502 70.2682C26.7439 70.2682 24.3486 66.042 23.6626 64.2826C23.1113 62.762 22.7612 61.1759 22.6212 59.5646C22.6197 59.5375 22.6247 59.5105 22.6357 59.4857C22.6466 59.4609 22.6633 59.4391 22.6843 59.422C22.7053 59.4048 22.73 59.3929 22.7565 59.3871C22.783 59.3813 22.8104 59.3818 22.8367 59.3886C27.7864 60.5826 32.8604 61.1853 37.9522 61.1839C39.1768 61.1839 40.3978 61.1839 41.6224 61.1516C46.7435 61.008 52.1411 60.7459 57.1796 59.7621C57.3053 59.7369 57.431 59.7154 57.5387 59.6831C65.4861 58.157 73.0493 53.3672 73.8178 41.2381C73.8465 40.7606 73.9184 36.2364 73.9184 35.7409C73.9219 34.0569 74.4606 23.7949 73.8393 17.4898Z" fill="url(#paint0_linear_549_34)"/>
+<path d="M61.2484 27.0263V48.114H52.8916V27.6475C52.8916 23.3388 51.096 21.1413 47.4437 21.1413C43.4287 21.1413 41.4177 23.7409 41.4177 28.8755V40.0782H33.1111V28.8755C33.1111 23.7409 31.0965 21.1413 27.0815 21.1413C23.4507 21.1413 21.6371 23.3388 21.6371 27.6475V48.114H13.2839V27.0263C13.2839 22.7176 14.384 19.2946 16.5843 16.7572C18.8539 14.2258 21.8311 12.926 25.5264 12.926C29.8036 12.926 33.0357 14.5705 35.1905 17.8559L37.2698 21.346L39.3527 17.8559C41.5074 14.5705 44.7395 12.926 49.0095 12.926C52.7013 12.926 55.6784 14.2258 57.9553 16.7572C60.1531 19.2922 61.2508 22.7152 61.2484 27.0263Z" fill="white"/>
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+<linearGradient id="paint0_linear_549_34" x1="37.0692" y1="0" x2="37.0692" y2="79" gradientUnits="userSpaceOnUse">
+<stop stop-color="#6364FF"/>
+<stop offset="1" stop-color="#563ACC"/>
+</linearGradient>
+</defs>
+</svg>

assets/js/event-bridge-for-activitypub-admin.js

@@ -0,0 +1,34 @@
+jQuery( function( $ ) {
+	// Accordion handling in various areas.
+	$( '.event-bridge-for-activitypub-settings-accordion' ).on( 'click', '.event-bridge-for-activitypub-settings-accordion-trigger', function() {
+		var isExpanded = ( 'true' === $( this ).attr( 'aria-expanded' ) );
+
+		if ( isExpanded ) {
+			$( this ).attr( 'aria-expanded', 'false' );
+			$( '#' + $( this ).attr( 'aria-controls' ) ).attr( 'hidden', true );
+		} else {
+			$( this ).attr( 'aria-expanded', 'true' );
+			$( '#' + $( this ).attr( 'aria-controls' ) ).attr( 'hidden', false );
+		}
+	} );
+
+	// Function to toggle visibility of custom details based on selected radio button.
+	function toggleCustomDetailsForSummary() {
+		if ($("#event_bridge_for_activitypub_summary_type_custom").is(':checked')) {
+			$("#event_bridge_for_activitypub_summary_type_custom-details").show();
+		} else {
+			$("#event_bridge_for_activitypub_summary_type_custom-details").hide();
+		}
+	}
+
+	// Run the toggle function on page load.
+	$(document).ready(function() {
+		window.console.log("test");
+		toggleCustomDetailsForSummary(); // Set the correct state on load.
+
+		// Listen for changes on the radio buttons
+		$("input[name=event_bridge_for_activitypub_summary_type]").change(function() {
+			toggleCustomDetailsForSummary(); // Update visibility on change.
+		});
+	});
+} );

bin/install-wp-tests.sh

@@ -0,0 +1,272 @@
+#!/usr/bin/env bash
+
+if [ $# -lt 3 ]; then
+	echo "usage: $0 <db-name> <db-user> <db-pass> [db-host] [wp-version] [skip-database-creation] [skip-wp-install] [skip-plugins] [skip-test-suite]"
+	exit 1
+fi
+
+DB_NAME=$1
+DB_USER=$2
+DB_PASS=$3
+DB_HOST=${4-localhost}
+WP_VERSION=${5-latest}
+SKIP_DB_CREATE=${6-false}
+SKIP_WP_INSTALL=${7-false}
+SKIP_PLUGINS_INSTALL=${8-false}
+SKIP_TEST_SUITE_INSTALL=${9-false}
+
+# Initialize the plugin list
+PLUGINS=""
+
+# Parse optional --plugins argument
+while [[ "$#" -gt 0 ]]; do
+    case $1 in
+        --plugins) PLUGINS="$2"; shift ;;
+    esac
+    shift
+done
+
+TMPDIR=${TMPDIR-/tmp}
+TMPDIR=$(echo $TMPDIR | sed -e "s/\/$//")
+WP_TESTS_DIR=${WP_TESTS_DIR-$TMPDIR/wordpress-tests-lib}
+WP_CORE_DIR=${WP_CORE_DIR-$TMPDIR/wordpress}
+
+download() {
+    if [ `which curl` ]; then
+        curl -s "$1" > "$2";
+    elif [ `which wget` ]; then
+        wget -nv -O "$2" "$1"
+    fi
+}
+
+if [[ $WP_VERSION =~ ^[0-9]+\.[0-9]+\-(beta|RC)[0-9]+$ ]]; then
+	WP_BRANCH=${WP_VERSION%\-*}
+	WP_TESTS_TAG="branches/$WP_BRANCH"
+
+elif [[ $WP_VERSION =~ ^[0-9]+\.[0-9]+$ ]]; then
+	WP_TESTS_TAG="branches/$WP_VERSION"
+elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0-9]+ ]]; then
+	if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+		# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+		WP_TESTS_TAG="tags/${WP_VERSION%??}"
+	else
+		WP_TESTS_TAG="tags/$WP_VERSION"
+	fi
+elif [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
+	WP_TESTS_TAG="trunk"
+else
+	# http serves a single offer, whereas https serves multiple. we only want one
+	download http://api.wordpress.org/core/version-check/1.7/ /tmp/wp-latest.json
+	grep '[0-9]+\.[0-9]+(\.[0-9]+)?' /tmp/wp-latest.json
+	LATEST_VERSION=$(grep -o '"version":"[^"]*' /tmp/wp-latest.json | sed 's/"version":"//')
+	if [[ -z "$LATEST_VERSION" ]]; then
+		echo "Latest WordPress version could not be found"
+		exit 1
+	fi
+	WP_TESTS_TAG="tags/$LATEST_VERSION"
+fi
+set -ex
+
+install_wp() {
+	if [ "$SKIP_WP_INSTALL" = "true" ]; then
+        echo "Skipping WordPress installation."
+        return 0
+    fi
+
+	if [ -d $WP_CORE_DIR ]; then
+		return;
+	fi
+
+	mkdir -p $WP_CORE_DIR
+
+	if [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
+		mkdir -p $TMPDIR/wordpress-trunk
+		rm -rf $TMPDIR/wordpress-trunk/*
+		svn export --quiet https://core.svn.wordpress.org/trunk $TMPDIR/wordpress-trunk/wordpress
+		mv $TMPDIR/wordpress-trunk/wordpress/* $WP_CORE_DIR
+	else
+		if [ $WP_VERSION == 'latest' ]; then
+			local ARCHIVE_NAME='latest'
+		elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+ ]]; then
+			# https serves multiple offers, whereas http serves single.
+			download https://api.wordpress.org/core/version-check/1.7/ $TMPDIR/wp-latest.json
+			if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+				# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+				LATEST_VERSION=${WP_VERSION%??}
+			else
+				# otherwise, scan the releases and get the most up to date minor version of the major release
+				local VERSION_ESCAPED=`echo $WP_VERSION | sed 's/\./\\\\./g'`
+				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' $TMPDIR/wp-latest.json | sed 's/"version":"//' | head -1)
+			fi
+			if [[ -z "$LATEST_VERSION" ]]; then
+				local ARCHIVE_NAME="wordpress-$WP_VERSION"
+			else
+				local ARCHIVE_NAME="wordpress-$LATEST_VERSION"
+			fi
+		else
+			local ARCHIVE_NAME="wordpress-$WP_VERSION"
+		fi
+		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  $TMPDIR/wordpress.tar.gz
+		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
+	fi
+
+	download https://raw.githubusercontent.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
+}
+
+install_test_suite() {
+	if [ "$SKIP_TEST_SUITE_INSTALL" = "true" ]; then
+        echo "Skipping test suite installation."
+        return 0
+    fi
+
+	# portable in-place argument for both GNU sed and Mac OSX sed
+	if [[ $(uname -s) == 'Darwin' ]]; then
+		local ioption='-i.bak'
+	else
+		local ioption='-i'
+	fi
+
+	# set up testing suite if it doesn't yet exist
+	if [ ! -d $WP_TESTS_DIR ]; then
+		# set up testing suite
+		mkdir -p $WP_TESTS_DIR
+		rm -rf $WP_TESTS_DIR/{includes,data}
+		svn export --quiet --ignore-externals https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/includes/ $WP_TESTS_DIR/includes
+		svn export --quiet --ignore-externals https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/data/ $WP_TESTS_DIR/data
+	fi
+
+	if [ ! -f wp-tests-config.php ]; then
+		download https://develop.svn.wordpress.org/${WP_TESTS_TAG}/wp-tests-config-sample.php "$WP_TESTS_DIR"/wp-tests-config.php
+		# remove all forward slashes in the end
+		WP_CORE_DIR=$(echo $WP_CORE_DIR | sed "s:/\+$::")
+		sed $ioption "s:dirname( __FILE__ ) . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s:__DIR__ . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/youremptytestdbnamehere/$DB_NAME/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/yourusernamehere/$DB_USER/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/yourpasswordhere/$DB_PASS/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s|localhost|${DB_HOST}|" "$WP_TESTS_DIR"/wp-tests-config.php
+	fi
+
+}
+
+recreate_db() {
+	shopt -s nocasematch
+	if [[ $1 =~ ^(y|yes)$ ]]
+	then
+		mysqladmin drop $DB_NAME -f --user="$DB_USER" --password="$DB_PASS"$EXTRA
+		create_db
+		echo "Recreated the database ($DB_NAME)."
+	else
+		echo "Leaving the existing database ($DB_NAME) in place."
+	fi
+	shopt -u nocasematch
+}
+
+create_db() {
+	mysqladmin create $DB_NAME --user="$DB_USER" --password="$DB_PASS"$EXTRA
+}
+
+install_db() {
+
+	if [ ${SKIP_DB_CREATE} = "true" ]; then
+		return 0
+	fi
+
+	# parse DB_HOST for port or socket references
+	local PARTS=(${DB_HOST//\:/ })
+	local DB_HOSTNAME=${PARTS[0]};
+	local DB_SOCK_OR_PORT=${PARTS[1]};
+	local EXTRA=""
+
+	if ! [ -z $DB_HOSTNAME ] ; then
+		if [ $(echo $DB_SOCK_OR_PORT | grep -e '^[0-9]\{1,\}$') ]; then
+			EXTRA=" --host=$DB_HOSTNAME --port=$DB_SOCK_OR_PORT --protocol=tcp"
+		elif ! [ -z $DB_SOCK_OR_PORT ] ; then
+			EXTRA=" --socket=$DB_SOCK_OR_PORT"
+		elif ! [ -z $DB_HOSTNAME ] ; then
+			EXTRA=" --host=$DB_HOSTNAME --protocol=tcp"
+		fi
+	fi
+
+	# create database
+	if [ $(mysql --user="$DB_USER" --password="$DB_PASS"$EXTRA --execute='show databases;' | grep ^$DB_NAME$) ]
+	then
+		echo "Reinstalling will delete the existing test database ($DB_NAME)"
+		recreate_db yes
+	else
+		create_db
+	fi
+}
+
+install_wp_plugin() {
+    PLUGIN_NAME=$1
+
+	mkdir -p "$WP_CORE_DIR/wp-content/plugins/"
+
+	if [ -d "$WP_CORE_DIR/wp-content/plugins/$PLUGIN_NAME" ]; then
+		return;
+	fi
+
+	# Get the latest tag.
+	if [ -z "$2" ]; then
+		LATEST_TAG=$(svn log https://plugins.svn.wordpress.org/$PLUGIN_NAME/tags --limit 1 | awk 'NR == 4 { print $4 }')
+		PLUGIN_VERSION=$LATEST_TAG
+	else
+		PLUGIN_VERSION=$2
+	fi
+	
+	if [ -n "$PLUGIN_VERSION" ]; then
+		PLUGIN_FILE="$PLUGIN_NAME.$PLUGIN_VERSION.zip"
+	else
+		PLUGIN_FILE="$PLUGIN_NAME.zip"
+	fi
+
+	URL="https://downloads.wordpress.org/plugin/$PLUGIN_FILE"
+
+    # Check if the plugin file already exists
+    if ! test -f "$TMPDIR/$PLUGIN_FILE"; then
+        download $URL "$TMPDIR/$PLUGIN_FILE"
+    fi
+
+    # Unzip the plugin into the WordPress must-use plugins directory
+    unzip -q -o "$TMPDIR/$PLUGIN_FILE" -d "$WP_CORE_DIR/wp-content/plugins/"
+}
+
+install_wp_plugin_mec() {
+	mkdir -p "$WP_CORE_DIR/wp-content/plugins/"
+
+	if [ -d "$WP_CORE_DIR/wp-content/plugins/modern-events-calendar-lite" ]; then
+		return;
+	fi
+
+	PLUGIN_VERSION="v7.15.0"
+
+    URL="https://code.event-federation.eu/Event-Federation/modern-events-calendar-lite"
+
+	git clone $URL "$WP_CORE_DIR/wp-content/plugins/modern-events-calendar-lite"
+}
+
+install_wp_plugins() {
+	if [ "$SKIP_PLUGINS_INSTALL" = "true" ]; then
+        echo "Skipping WordPress plugin installation."
+        return 0
+    fi
+	# Install the one and only ActivityPub plugin (greetings @pfefferle).
+	install_wp_plugin activitypub
+	# Install (not-activate) all supported event plugins.
+	install_wp_plugin the-events-calendar "6.8.1"
+	install_wp_plugin very-simple-event-list
+	install_wp_plugin gatherpress
+	install_wp_plugin eventprime-event-calendar-management
+	install_wp_plugin events-manager "6.6.3"
+	install_wp_plugin wp-event-manager "3.1.45.1"
+	install_wp_plugin wp-event-solution "4.0.14"
+	install_wp_plugin event-organiser "3.12.8"
+	# Mec is not installable via wordpress.org, we use our own mirror.
+	install_wp_plugin_mec
+}
+
+install_wp
+install_wp_plugins
+install_test_suite
+install_db

composer.json

@@ -1,18 +1,23 @@
 {
-    "name": "menrath/wordpress-activitypub-event-extensions",
-    "description": "The ActivityPub Event Extensions help for event custom post types to federate properly.",
+    "name": "menrath/wordpress-event-bridge-for-activitypub",
+    "version": "1.0.0",
+    "description": "The Event Bridge for ActivityPub help for event custom post types to federate properly.",
     "type": "wordpress-plugin",
     "require": {
-        "php": ">=5.6.0",
-        "composer/installers": "^1.0 || ^2.0"
+        "php": ">=7.4.0",
+        "composer/installers": "^2.0"
     },
     "require-dev": {
+        "phpunit/phpunit": "^5.7.21 || ^6.5 || ^7.5 || ^8",
         "phpcompatibility/php-compatibility": "*",
         "phpcompatibility/phpcompatibility-wp": "*",
         "squizlabs/php_codesniffer": "3.*",
         "wp-coding-standards/wpcs": "dev-develop",
+        "yoast/phpunit-polyfills": "^3.0",
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0.0",
-        "sirbrillig/phpcs-variable-analysis": "^2.11"
+        "sirbrillig/phpcs-variable-analysis": "^2.11",
+        "phpcsstandards/phpcsextra": "^1.1.0",
+        "dms/phpunit-arraysubset-asserts": "^0.5.0"
     },
     "config": {
         "allow-plugins": true
@@ -28,14 +33,45 @@
         }
     ],
     "extra": {
-        "installer-name": "activitypub-event-extensions"
+        "installer-name": "event-bridge-for-activitypub"
     },
     "scripts": {
         "lint": [
-            "vendor/bin/phpcs -n -q"
+            "vendor/bin/phpcs"
         ],
         "lint:fix": [
             "vendor/bin/phpcbf"
-        ]
+        ],
+        "prepare-test": [
+            "composer install",
+            "bin/install-wp-tests.sh wordpress-test root wordpress-test test-db latest true"
+        ],
+        "test": [
+            "@prepare-test",
+            "@test-vs-event-list",
+            "@test-the-events-calendar",
+            "@test-gatherpress",
+            "@test-events-manager",
+            "@test-wp-event-manager",
+            "@test-eventin",
+            "@test-modern-events-calendar-lite",
+            "@test-eventprime",
+            "@test-event-organiser"
+        ],
+        "test-debug": [
+            "@prepare-test",
+            "@test-event-bridge-for-activitypub-shortcodes"
+        ],
+        "test-vs-event-list": "phpunit --filter=vs_event_list",
+        "test-the-events-calendar": "phpunit --filter=the_events_calendar",
+        "test-gatherpress": "phpunit --filter=gatherpress",
+        "test-events-manager": "phpunit --filter=events_manager",
+        "test-wp-event-manager": "phpunit --filter=wp_event_manager",
+        "test-eventin": "phpunit --filter=eventin",
+        "test-modern-events-calendar-lite": "phpunit --filter=modern_events_calendar_lite",
+        "test-eventprime": "phpunit --filter=eventprime",
+        "test-event-organiser": "phpunit --filter=event_organiser",
+        "test-event-bridge-for-activitypub-shortcodes": "phpunit --filter=event_bridge_for_activitypub_shortcodes",
+        "test-all": "phpunit"
     }
 }

docker-compose.yml

@@ -0,0 +1,50 @@
+version: '3'
+
+# This files purpose is to run the PHPunit tests locally.
+# Prerequisites:
+# Run "composer install" to generate a composer.lock file and install PHP dev dependencies.
+#
+# Install docker and docker compose and than just run:
+# docker compose up
+
+# To live debug in VSCode add this launch configuration to your .vscode/launch.json.
+# It assumes that the WordPress root-dir is your workspace root.
+#
+# {
+#   "name": "Listen for PHPUnit",
+#   "type": "php",
+#   "request": "launch",
+#   "port": 9003,
+#   "pathMappings": {
+#    "/app/": "${workspaceRoot}/wp-content/plugins/event-bridge-for-activitypub/",
+#    "/tmp/wordpress/": "${workspaceRoot}/"
+#   },
+# },
+
+services:
+  test-db:
+    image: mariadb
+    environment:
+      MARIADB_DATABASE: wordpress-test
+      MARIADB_ROOT_PASSWORD: wordpress-test
+    healthcheck:
+      test: ["CMD", "healthcheck.sh", "--connect", "--innodb_initialized"]
+      start_period: 2s
+      interval: 1s
+      timeout: 5s
+      retries: 10
+
+  test-php:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    depends_on:
+      test-db:
+        condition: service_healthy
+    links:
+      - test-db
+    volumes:
+      - .:/app
+    command: ["composer", "run-script", "test-debug"]
+    extra_hosts:
+      - "host.docker.internal:host-gateway"

docs/add_your_event_plugin.md

@@ -0,0 +1,222 @@
+# Write a specialized ActivityPub transformer for an Event-Custom-Post-Type
+
+> **_NOTE:_** This documentation is also likely to be useful for content types other than events.
+
+The ActivityPub plugin offers a basic support for all post types out of the box, but it also allows the registration of external transformers. A transformer is a class that implements the [abstract transformer class](https://github.com/Automattic/wordpress-activitypub/blob/fb0e23e8854d149fdedaca7a9ea856f5fd965ec9/includes/transformer/class-base.php) and is responsible for generating the ActivityPub JSON representation of an WordPress post or comment object. 
+
+## How it works
+
+To make the WordPress ActivityPub plugin use a custom transformer simply add a filter to the `activitypub_transformer` hook which provides access to the transformer factory. The [transformer factory](https://github.com/Automattic/wordpress-activitypub/blob/master/includes/transformer/class-factory.php#L12) determines which transformer is used to transform a WordPress object to ActivityPub. We provide a parent event transformer, that comes with common tasks needed for events. Furthermore, we provide admin notices, to prevent users from misconfiguration issues.
+
+## Add your event plugin
+
+First you need to add some basic information about your event plugin. Just create a new file in `./includes/plugins/my-event-plugin.php`. Implement at least all abstract functions of the `Event_Plugin` class.
+
+```php
+  namespace Event_Bridge_For_ActivityPub\Integrations;
+
+  // Exit if accessed directly.
+  defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+  /**
+   * Integration information for My Event Plugin
+   *
+   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
+   *
+   * @since 1.0.0
+   */
+  final class My_Event_Plugin extends Event_Plugin {
+```
+
+Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_CLASSES` constant in the `includes/setup.php` file:
+
+```php
+	private const EVENT_PLUGIN_CLASSES = array(
+		...
+		'\Event_Bridge_For_ActivityPub\Integrations\My_Event_Plugin',
+	);
+```
+
+The Event Bridge for ActivityPub then takes care of applying the transformer, so you can jump right into implementing it.
+
+## Writing an event transformer class
+
+Within WordPress most content types are stored as a custom post type in the posts table. The ActivityPub plugin offers a basic support for all post types out of the box. So-called transformers take care of converting WordPress WP_Post objects to ActivityStreams JSON. The ActivityPub plugin offers a generic transformer for all post types. Additionally, custom transformers can be implemented to better fit a custom post type, and they can be easily registered with the ActivityPub plugin.
+
+If you are writing a transformer for your event post type we recommend to start by extending the provided [event transformer](./includes/activitypub/transformer/class-event.php). It is an extension of the default generic post transformer and inherits useful default implementations for generating the [attachments](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-attachment), rendering a proper [content](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-content) in HTML from either blocks or the classic editor, extracting [tags](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-tag) and more. Furthermore, it offers functions which are likely to be shared by multiple event plugins, so you do not need to reimplement those, or you can fork and extend them to your needs.
+
+So create a new file at `./includes/activitypub/transformer/my-event-plugin.php`.
+
+```php
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+
+/**
+ * ActivityPub Transformer for My Event Plugin' event post type.
+ */
+class My_Event_Plugin extends Event_Transformer; {
+```
+
+The main function which controls the transformation is `to_object`. This one is called by the ActivityPub plugin to get the resulting ActivityStreams represented by a PHP-object (`\Activitypub\Activity\Object\Extended_Object\Event`). The conversion to the actual JSON-LD takes place later, and you don't need to cover that (> `to_array` > associative array > `to_json` > JSON).
+The chances are good that you will not need to override that function.
+
+
+```php
+/**
+  * Transform the WordPress Object into an ActivityPub Event Object.
+  *
+  * @return Activitypub\Activity\Extended_Object\Event
+  */
+public function to_object() {
+  $activitypub_object = parent::to_object();
+  // ... your additions.
+  return $activitypub_object;
+}
+```
+
+We also recommend extending the constructor of the transformer class and set a specialized API object of the event, if it is available. For instance:
+
+```php
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->event_api = new My_Event_Object_API( $wp_object );
+	}
+```
+
+The ActivityPub object classes contain dynamic getter and setter functions: `set_<property>()` and `get_<property>()`. The function `transform_object_properties()` usually called by `to_object()` tries to set all properties known to the target ActivityPub object where a function called `get_<property>` exists in the current transformer class.
+
+### How to add new properties
+
+Adding new properties is not encouraged to do at the transformer level. It's recommended to create a proper target ActivityPub object first. The target ActivityPub object also controls the JSON-LD context via the constant `JSON_LD_CONTEXT`. [Example](https://github.com/Automattic/wordpress-activitypub/blob/fb0e23e8854d149fdedaca7a9ea856f5fd965ec9/includes/activity/extended-object/class-event.php#L21).
+
+
+### Properties
+
+> **_NOTE:_** Within PHP all properties are snake_case, they will be transformed to the according CamelCase by the ActivityPub plugin. So if to you set `start_time` by using the ActivityPub objects class function `set_start_time` or implementing a getter function in the transformer class called `get_start_time` the property `startTime` will be set accordingly in the JSON representation of the resulting ActivityPub object.
+
+You can find all available event related properties in the [event class](https://github.com/Automattic/wordpress-activitypub/blob/master/includes/activity/extended-object/class-event.php) along documentation and with links to the specifications.
+
+####  Mandatory fields
+
+In order to ensure your events are compatible with other ActivityPub Event implementations there are several required properties that must be set by your transformer.
+
+* **[`type`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-type)**: if using the `Activitypub\Activity\Extended_Object\Event` class the type will default to `Event` without doing anything.
+
+* **[`startTime`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-startTime)**: the events start time
+
+* **[`name`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-name)**: the title of the event
+
+#### Checklist for properties you SHOULD at least consider writing a getter functions for
+
+* **`endTime`**
+* **`location`** – Note: the `address` within can be both a `string` or a `PostalAddress`.
+* **`isOnline`**
+* **`status`**
+* **`get_tag`**
+* **`timezone`**
+* **`commentsEnabled`**
+
+## Writing integration tests
+
+Create a new tests class in `tests/test-class-plugin-my-event-plugin.php`.
+
+```
+/**
+ * Sample test case.
+ */
+class Test_My_Event_Plugin extends WP_UnitTestCase {
+```
+
+Implement a check whether your event plugin is active in the `set_up` function. It may be the presence of a class, function or constant.
+
+```php
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! <TODO:my-event-plugin-is-active> ) {
+			self::markTestSkipped( 'The Events Calendar plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+```
+
+## Running the tests for your plugin/ add the tests to the CI pipeline
+
+### Install the plugin in the CI
+
+The tests are set up by the bash script in `bin/install-wp-tests.sh`. Make sure your WordPress Event plugin is installed within the function `install_wp_plugins`.
+
+### Add a composer script for your plugin
+
+In the pipeline we want to run each event plugins integration tests in a single command, to achieve that, we use phpunit's filters.
+
+```json
+{
+  "scripts": {
+    ...
+    "test": [
+              ...
+              "@test-my-event-plugin"
+          ],
+          ...
+          "@test-my-event-plugin": "phpunit --filter=my_event_plugin",
+    ]
+  }
+}
+```
+
+### Load your plugin during the tests
+
+To activate/load your plugin add it to the switch statement within the function `_manually_load_plugin()` within `tests/bootstrap.php`.
+
+```php
+	switch ( $event_bridge_for_activitypub_integration_filter ) {
+    ...
+    case 'my_event_plugin':
+			$plugin_file = 'my-event-plugin/my-event-plugin.php';
+			break;
+```
+
+If you want to run your tests locally just change the `test-debug` script in the `composer.json` file:
+
+```json
+    "test-debug": [
+        "@prepare-test",
+        "@test-my-event-plugin"
+    ],
+```
+
+Now you just can execute `docker compose up` to run the tests (make sure you have the latest docker and docker-compose installed).
+
+### Debugging the tests
+
+If you are using Visual Studio Code or VSCodium you can step-debug within the tests by adding this configuration to your `.vscode/launch.json`:
+
+```json
+{
+  "version": "0.2.0",
+  "configurations": [
+    ...,
+    {
+      "name": "Listen for PHPUnit",
+      "type": "php",
+      "request": "launch",
+      "port": 9003,
+      "pathMappings": {
+      "/app/": "${workspaceRoot}/wp-content/plugins/event-bridge-for-activitypub/",
+      "/tmp/wordpress/": "${workspaceRoot}/"
+      },
+    }
+  ]
+}
+```

event-bridge-for-activitypub.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * Plugin Name:  Event Bridge for ActivityPub
+ * Description:  Integrating popular event plugins with the ActivityPub plugin.
+ * Plugin URI:   https://event-federation.eu/
+ * Version:      0.3.3
+ * Author:       André Menrath
+ * Author URI:   https://graz.social/@linos
+ * Text Domain:  event-bridge-for-activitypub
+ * License:      AGPL-3.0-or-later
+ * License URI:  https://www.gnu.org/licenses/agpl-3.0.html
+ * Requires PHP: 7.4
+ *
+ * Requires at least ActivityPub plugin with version >= 3.2.2. ActivityPub plugin tested up to: 4.3.0.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_BASENAME', plugin_basename( __FILE__ ) );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE', plugin_dir_path( __FILE__ ) . '/' . basename( __FILE__ ) );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION', current( get_file_data( __FILE__, array( 'Version' ), 'plugin' ) ) );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_DOMAIN', 'event-bridge-for-activitypub' );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_ACTIVITYPUB_PLUGIN_MIN_VERSION', '3.2.2' );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY', "<ul>\n  <li>[ap_start_time]</li>\n  <li>[ap_end_time]</li>\n  <li>[ap_location]</li>\n</ul>\n[ap_hashcats] [ap_hashtags]" );
+define( 'EVENT_BRIDGE_FOR_ACTIVITYPUB_DEFAULT_SUMMARY_TYPE', 'preset' );
+
+// Include and register the autoloader class for automatic loading of plugin classes.
+require_once EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . '/includes/class-autoloader.php';
+Event_Bridge_For_ActivityPub\Autoloader::register();
+
+// Initialize the plugin.
+Event_Bridge_For_ActivityPub\Setup::get_instance();

includes/activitypub/handler/class-join.php

@@ -1,6 +0,0 @@
-<?php
-/**
- * Handling Event Joins.
- *
- * @package activitypub-event-extensions
- */

includes/activitypub/transformer/class-event-organiser.php

@@ -0,0 +1,99 @@
+<?php
+/**
+ * ActivityPub Transformer for the plugin Event Organiser.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+
+/**
+ * ActivityPub Transformer for Event Organiser.
+ *
+ * @since 1.0.0
+ */
+final class Event_Organiser extends Event {
+	/**
+	 * Extended constructor.
+	 *
+	 * The wp_object is overridden with a the wp_object with filters. This object
+	 * also contains attributes specific to the Event organiser plugin like the
+	 * occurrence id.
+	 *
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
+	 */
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->wp_object = get_posts(
+			array(
+				'ID'               => $wp_object->ID,
+				'post_type'        => 'event',
+				'suppress_filters' => false,
+			)
+		)[0];
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_end_time(): ?string {
+		return eo_get_the_end( 'Y-m-d\TH:i:s\Z', $this->wp_object->ID, $this->wp_object->occurrence_id );
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_start_time(): string {
+		return eo_get_the_start( 'Y-m-d\TH:i:s\Z', $this->wp_object->ID, $this->wp_object->occurrence_id );
+	}
+
+	/**
+	 * Get location from the event object.
+	 */
+	public function get_location(): ?Place {
+		$venue_id = eo_get_venue( $this->wp_object->ID );
+
+		if ( ! $venue_id ) {
+			return null;
+		}
+
+		$address = eo_get_venue_address( $venue_id );
+
+		$venue_name = eo_get_venue_name( $venue_id );
+
+		$address['streetAddress'] = $address['address'];
+		unset( $address['address'] );
+
+		$address['postalCode'] = $address['postcode'];
+		unset( $address['postcode'] );
+
+		$address['addressRegion'] = $address['state'];
+		unset( $address['state'] );
+
+		$address['addressLocality'] = $address['city'];
+		unset( $address['city'] );
+
+		$address['addressCountry'] = $address['country'];
+		unset( $address['country'] );
+
+		$address['type'] = 'PostalAddress';
+
+		$location = new Place();
+		$location->set_name( eo_get_venue_name( $this->wp_object->ID ) );
+		$location->set_latitude( eo_get_venue_lat( $this->wp_object->ID ) ?? null );
+		$location->set_longitude( eo_get_venue_lng( $this->wp_object->ID ) ?? null );
+		$location->set_address( $address );
+		$location->set_name( $venue_name );
+		$location->set_content( eo_get_venue_description( $venue_id ) );
+
+		return $location;
+	}
+}

includes/activitypub/transformer/class-event.php

@@ -0,0 +1,595 @@
+<?php
+/**
+ * Replace the default ActivityPub Transformer
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Event as Event_Object;
+use Activitypub\Activity\Extended_Object\Place;
+use Activitypub\Shortcodes;
+use Activitypub\Transformer\Post;
+
+use DateTime;
+
+/**
+ * Base transformer for WordPress event post types to ActivityPub events.
+ *
+ * Everything that transforming several WordPress post types that represent events
+ * have in common, as well as sane defaults for events should be defined here.
+ *
+ * BeforeFirstRelease:
+ * [ ] remove link at the end of the content.
+ * [ ] add organizer.
+ * [ ] do add Cancelled reason in the content.
+ */
+abstract class Event extends Post {
+
+	/**
+	 * The WordPress event taxonomy.
+	 *
+	 * @var string
+	 */
+	protected $wp_taxonomy;
+
+	/**
+	 * Returns the ActivityStreams 2.0 Object-Type for an Event.
+	 *
+	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event
+	 *
+	 * @return string The Event Object-Type.
+	 */
+	protected function get_type(): string {
+		return 'Event';
+	}
+
+	/**
+	 * Get a sane default for whether comments are enabled.
+	 */
+	protected function get_comments_enabled(): ?bool {
+		return comments_open( $this->wp_object );
+	}
+
+	/**
+	 * Set a hardcoded template for the content.
+	 *
+	 * This actually disabled templates for the content.
+	 * Maybe this independent templates for events will be added later.
+	 */
+	protected function get_post_content_template(): string {
+		return '[ap_content]';
+	}
+
+	/**
+	 * Returns the title of the event.
+	 *
+	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-name
+	 *
+	 * @return string The name.
+	 */
+	protected function get_name(): string {
+		return $this->wp_object->post_title;
+	}
+
+	/**
+	 * Extend the construction of the Post Transformer to also set the according taxonomy of the event post type.
+	 *
+	 * @param WP_Post $wp_object The WordPress post object (event).
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
+	 */
+	public function __construct( $wp_object, $wp_taxonomy = 'category' ) {
+		parent::__construct( $wp_object );
+		$this->wp_taxonomy = $wp_taxonomy;
+	}
+
+	/**
+	 * Extract the join mode.
+	 *
+	 * Currently we don't handle joins, we always mark events as external.
+	 *
+	 * @return string
+	 */
+	public function get_join_mode(): ?string {
+		return 'external';
+	}
+
+	/**
+	 * Extract the external participation url.
+	 *
+	 * Currently we don't handle joins, we always mark events as external.
+	 * We just link back to the events HTML representation on our WordPress site.
+	 *
+	 * @return ?string The external participation URL.
+	 */
+	public function get_external_participation_url(): ?string {
+		return 'external' === $this->get_join_mode() ? $this->get_url() : null;
+	}
+
+	/**
+	 * Set the event category, via the mapping setting.
+	 *
+	 * @return ?string
+	 */
+	public function get_category(): ?string {
+		if ( is_null( $this->wp_taxonomy ) ) {
+			return null;
+		}
+		$current_category_mapping = \get_option( 'event_bridge_for_activitypub_event_category_mappings', array() );
+		$terms                    = \get_the_terms( $this->wp_object, $this->wp_taxonomy );
+
+		// Check if the event has a category set and if that category has a specific mapping return that one.
+		if ( ! is_wp_error( $terms ) && $terms && array_key_exists( $terms[0]->slug, $current_category_mapping ) ) {
+			return sanitize_text_field( $current_category_mapping[ $terms[0]->slug ] );
+		} else {
+			// Return the default event category.
+			return sanitize_text_field( \get_option( 'event_bridge_for_activitypub_default_event_category', 'MEETING' ) );
+		}
+	}
+
+	/**
+	 * Retrieves the excerpt text (may be HTML). Used for constructing the summary.
+	 *
+	 * @return ?string
+	 */
+	protected function retrieve_excerpt(): ?string {
+		if ( $this->wp_object->post_excerpt ) {
+			return $this->wp_object->post_excerpt;
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Get the start time.
+	 *
+	 * This is mandatory and must be implemented in the final event transformer class.
+	 */
+	abstract public function get_start_time(): string;
+
+	/**
+	 * Get the end time.
+	 *
+	 * This is not mandatory and therefore just return null by default.
+	 */
+	public function get_end_time(): ?string {
+		return null;
+	}
+
+	/**
+	 * Get a default for the location.
+	 *
+	 * This should be overridden in the actual event transformer.
+	 */
+	public function get_location(): ?Place {
+		return null;
+	}
+
+	/**
+	 * Default value for the event status.
+	 */
+	public function get_status(): ?string {
+		return 'CONFIRMED';
+	}
+
+	/**
+	 * Compose a human readable formatted start time.
+	 */
+	protected function format_start_time(): string {
+		return $this->format_time( $this->get_start_time() );
+	}
+
+	/**
+	 * Compose a human readable formatted end time.
+	 */
+	protected function format_end_time(): string {
+		return $this->format_time( $this->get_end_time() );
+	}
+
+	/**
+	 * Compose a human readable formatted time.
+	 *
+	 * @param ?string $time The time which needs to be formatted.
+	 */
+	protected static function format_time( $time ) {
+		if ( is_null( $time ) ) {
+			return '';
+		}
+		$start_datetime  = new DateTime( $time );
+		$start_timestamp = $start_datetime->getTimestamp();
+		$datetime_format = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
+		return wp_date( $datetime_format, $start_timestamp );
+	}
+
+	/**
+	 * Generates output for the 'ap_start_time' shortcode.
+	 *
+	 * @param ?array $atts  The shortcode's attributes.
+	 * @return string The formatted start date and time of the event.
+	 */
+	public function shortcode_start_time( $atts ) {
+		$start_timestamp = $this->get_start_time();
+		return $this->generate_time_output( $start_timestamp, $atts, '🗓️', __( 'Start', 'event-bridge-for-activitypub' ) );
+	}
+
+	/**
+	 * Generates output for the 'ap_end_time' shortcode.
+	 *
+	 * @param ?array $atts  The shortcode's attributes.
+	 * @return string The formatted end date and time of the event.
+	 */
+	public function shortcode_end_time( $atts ) {
+		$end_timestamp = $this->get_end_time();
+		return $this->generate_time_output( $end_timestamp, $atts, '⏳', __( 'End', 'event-bridge-for-activitypub' ) );
+	}
+
+	/**
+	 * Generates the formatted time output for a shortcode.
+	 *
+	 * @param int|null $timestamp  The timestamp for the event time.
+	 * @param array    $atts       The shortcode attributes.
+	 * @param string   $icon       The icon to display.
+	 * @param string   $label      The label to display (e.g., 'Start', 'End').
+	 * @return string The formatted date and time, or an empty string if the timestamp is invalid.
+	 */
+	private function generate_time_output( $timestamp, $atts, $icon, $label ) {
+		if ( ! $timestamp ) {
+			return '';
+		}
+
+		$args = shortcode_atts(
+			array(
+				'icon'  => 'true',
+				'label' => 'true',
+			),
+			$atts
+		);
+
+		$args['icon']  = filter_var( $args['icon'], FILTER_VALIDATE_BOOLEAN );
+		$args['label'] = filter_var( $args['label'], FILTER_VALIDATE_BOOLEAN );
+
+		$output = array();
+
+		if ( $args['icon'] ) {
+			$output[] = $icon;
+		}
+
+		if ( $args['label'] ) {
+			$output[] = $label . ':';
+		}
+
+		$output[] = self::format_time( $timestamp );
+
+		return implode( ' ', $output );
+	}
+
+	/**
+	 * Generates output for the 'ap_location' shortcode.
+	 *
+	 * @param ?array $atts The shortcode's attributes.
+	 * @return string The formatted location/address of the event.
+	 */
+	public function shortcode_location( $atts ) {
+		$args = shortcode_atts(
+			array(
+				'icon'    => 'true',
+				'label'   => 'true',
+				'country' => 'true',
+				'zip'     => 'true',
+				'city'    => 'true',
+				'street'  => 'true',
+				'name'    => 'true',
+			),
+			$atts,
+			'ap_location'
+		);
+
+		// Convert attributes to booleans.
+		$args = array_map(
+			function ( $value ) {
+				return filter_var( $value, FILTER_VALIDATE_BOOLEAN );
+			},
+			$args
+		);
+
+		$location = $this->get_location();
+		if ( ! $location ) {
+			return '';
+		}
+
+		$output = array();
+		if ( $args['icon'] ) {
+			$output[] = '📍';
+		}
+		if ( $args['label'] ) {
+			$output[] = esc_html__( 'Location', 'event-bridge-for-activitypub' ) . ':';
+		}
+
+		$output[] = self::format_address( $location->get_address(), $args );
+
+		// Join output array into a single string with spaces and return.
+		return implode( ' ', array_filter( $output ) );
+	}
+
+	/**
+	 * Formats the address based on provided arguments.
+	 *
+	 * @param mixed $address The address data, either as a string or an array.
+	 * @param array $args    The arguments for which components to include.
+	 * @return string The formatted address.
+	 */
+	protected static function format_address( $address, $args = null ) {
+		if ( is_string( $address ) ) {
+			return esc_html( $address );
+		}
+
+		if ( is_null( $args ) ) {
+			$args = array(
+				'icon'    => 'true',
+				'title'   => 'true',
+				'country' => 'true',
+				'zip'     => 'true',
+				'city'    => 'true',
+				'street'  => 'true',
+				'name'    => 'true',
+			);
+		}
+
+		if ( is_array( $address ) ) {
+			$address_parts = array();
+
+			$components = array(
+				'name'    => 'name',
+				'street'  => 'streetAddress',
+				'zip'     => 'postalCode',
+				'city'    => 'addressLocality',
+				'country' => 'addressCountry',
+			);
+
+			foreach ( $components as $arg_key => $address_key ) {
+				if ( $args[ $arg_key ] && ! empty( $address[ $address_key ] ) ) {
+					$address_parts[] = esc_html( $address[ $address_key ] );
+				}
+			}
+
+			return implode( ', ', $address_parts );
+		}
+
+		return '';
+	}
+
+	/**
+	 * Format the category using the translation.
+	 */
+	protected function format_categories(): string {
+		if ( is_null( $this->wp_taxonomy ) ) {
+			return '';
+		}
+		$categories = array();
+
+		// Add the federated category string.
+		require_once EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . '/includes/event-categories.php';
+		$federated_category = $this->get_category();
+		if ( array_key_exists( $federated_category, EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES ) ) {
+			$categories[] = EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES[ $federated_category ];
+		}
+
+		// Add all category terms.
+		$terms = \get_the_terms( $this->wp_object, $this->wp_taxonomy );
+		if ( $terms && ! is_wp_error( $terms ) ) {
+			foreach ( $terms as $term ) {
+				$categories[] = $term->name;
+			}
+		}
+
+		if ( ! empty( $categories ) ) {
+			return implode( ' · ', array_unique( $categories ) );
+		}
+		return '';
+	}
+
+	/**
+	 * Register the shortcodes.
+	 */
+	public function register_shortcodes() {
+		foreach ( get_class_methods( self::class ) as $function ) {
+			if ( 'shortcode_' === substr( $function, 0, 10 ) ) {
+				add_shortcode( 'ap_' . substr( $function, 10, strlen( $function ) ), array( $this, $function ) );
+			}
+		}
+	}
+
+	/**
+	 * Register the shortcodes.
+	 */
+	public function unregister_shortcodes() {
+		foreach ( get_class_methods( self::class ) as $function ) {
+			if ( 'shortcode_' === substr( $function, 0, 10 ) ) {
+				remove_shortcode( 'ap_' . substr( $function, 10, strlen( $function ) ), array( $this, $function ) );
+			}
+		}
+	}
+
+	/**
+	 * Get the summary.
+	 */
+	public function get_summary(): ?string {
+		if ( 'preset' === get_option( 'event_bridge_for_activitypub_summary_type', 'preset' ) ) {
+			return $this->format_preset_summary();
+		}
+
+		// phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
+		$post    = $this->wp_object;
+		$summary = $this->get_event_summary_template();
+
+		// It seems that shortcodes are only applied to published posts.
+		if ( is_preview() ) {
+			$post->post_status = 'publish';
+		}
+
+		// Register our shortcodes just in time.
+
+		Shortcodes::register();
+		$this->register_shortcodes();
+
+		// Fill in the shortcodes.
+		\setup_postdata( $post );
+		$summary = \do_shortcode( $summary );
+		\wp_reset_postdata();
+
+		$summary = \wpautop( $summary );
+		$summary = \preg_replace( '/[\n\r\t]/', '', $summary );
+		$summary = \trim( $summary );
+
+		$summary = \apply_filters( 'event_bridge_for_activitypub_the_summary', $summary, $post );
+
+		// Unregister the shortcodes.
+		Shortcodes::unregister();
+		$this->unregister_shortcodes();
+
+		return $summary;
+	}
+
+	/**
+	 * Create a custom summary.
+	 *
+	 * It contains also the most important meta-information. The summary is often used when the
+	 * ActivityPub object type 'Event' is not supported, e.g. in Mastodon.
+	 *
+	 * @return string $summary The custom event summary.
+	 */
+	public function format_preset_summary(): ?string {
+		add_filter( 'activitypub_object_content_template', array( self::class, 'remove_ap_permalink_from_template' ), 2, 2 );
+		$excerpt = $this->retrieve_excerpt();
+		// BeforeFirstRelease: decide whether this should be a admin setting.
+		$fallback_to_content = false;
+		if ( is_null( $excerpt ) && $fallback_to_content ) {
+			$excerpt = $this->get_content();
+		}
+		remove_filter( 'activitypub_object_content_template', array( self::class, 'remove_ap_permalink_from_template' ) );
+
+		$category   = $this->format_categories();
+		$start_time = $this->get_start_time();
+		$end_time   = $this->get_end_time();
+		$address    = $this->format_address( $this->get_location() );
+		$time_atts  = array(
+			'icon'  => true,
+			'label' => true,
+		);
+
+		$formatted_items = array();
+		if ( ! empty( $category ) ) {
+			$formatted_items[] = '🏷️ ' . __( 'Category', 'event-bridge-for-activitypub' ) . ': ' . $category;
+		}
+
+		if ( ! empty( $start_time ) ) {
+			$formatted_items[] = $this->generate_time_output( $start_time, $time_atts, '🗓️', __( 'Start', 'event-bridge-for-activitypub' ) );
+		}
+
+		if ( ! empty( $end_time ) ) {
+			$formatted_items[] = $this->generate_time_output( $end_time, $time_atts, '⏳', __( 'End', 'event-bridge-for-activitypub' ) );
+		}
+
+		if ( ! empty( $address ) ) {
+			$formatted_items[] = '📍 ' . __( 'Address', 'event-bridge-for-activitypub' ) . ': ' . $address;
+		}
+
+		// Compose the summary based on the number of meta items.
+		if ( count( $formatted_items ) > 1 ) {
+			$summary = '<ul><li>' . implode( '</li><li>', $formatted_items ) . '</li></ul>';
+		} elseif ( 1 === count( $formatted_items ) ) {
+			$summary = $formatted_items[0]; // Just the one item without <ul><li>.
+		} else {
+			$summary = ''; // No items, so no output.
+		}
+
+		$summary .= $excerpt;
+		return $summary;
+	}
+
+	/**
+	 * Gets the template to use to generate the summary of the ActivityStreams representation of an event post.
+	 *
+	 * @return string The Template.
+	 */
+	protected function get_event_summary_template() {
+		$summary  = \get_option( 'event_bridge_for_activitypub_custom_summary', EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY );
+		$template = $summary ?? EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY;
+
+		return apply_filters( 'event_bridge_for_activitypub_summary_template', $template, $this->wp_object );
+	}
+
+	/**
+	 * By default set the timezone of the WordPress site.
+	 *
+	 * This is likely to be overwritten by the actual transformer.
+	 *
+	 * @return string  The timezone string of the site.
+	 */
+	public function get_timezone(): string {
+		return wp_timezone_string();
+	}
+
+	/**
+	 * Remove the permalink shortcode from a WordPress template.
+	 *
+	 * This used for the summary template, because the summary usually gets,
+	 * used when converting a object, where the URL is usually appended anyway.
+	 *
+	 * @param string             $template The template string.
+	 * @param WP_Post|WP_Comment $wp_object The wp_object which was used to select the template.
+	 */
+	public static function remove_ap_permalink_from_template( $template, $wp_object ) {
+
+		// we could override the template here, to get out custom template from an option.
+
+		if ( 'event' === $wp_object->post_type ) {
+			$template = str_replace( '[ap_permalink]', '', $template );
+			$template = str_replace( '[ap_permalink type="html"]', '', $template );
+		}
+
+		return $template;
+	}
+
+	/**
+	 * Generic function that converts an WP-Event object to an ActivityPub-Event object.
+	 *
+	 * @return Event_Object
+	 */
+	public function to_object(): Event_Object {
+		$activitypub_object = new Event_Object();
+		$activitypub_object = $this->transform_object_properties( $activitypub_object );
+
+		// maybe move the following logic (till end of the function) into getter functions.
+
+		$published = \strtotime( $this->wp_object->post_date_gmt );
+
+		$activitypub_object->set_published( \gmdate( 'Y-m-d\TH:i:s\Z', $published ) );
+
+		$updated = \strtotime( $this->wp_object->post_modified_gmt );
+
+		if ( $updated > $published ) {
+			$activitypub_object->set_updated( \gmdate( 'Y-m-d\TH:i:s\Z', $updated ) );
+		}
+
+		$activitypub_object->set_content_map(
+			array(
+				$this->get_locale() => $this->get_content(),
+			)
+		);
+
+		$activitypub_object->set_to(
+			array(
+				'https://www.w3.org/ns/activitystreams#Public',
+				$this->get_actor_object()->get_followers(), // this fails on my machine.
+			)
+		);
+
+		return $activitypub_object;
+	}
+}

includes/activitypub/transformer/class-eventin.php

@@ -0,0 +1,164 @@
+<?php
+/**
+ * ActivityPub Transformer for Events managed with Eventin.
+ *
+ * @link https://support.themewinter.com/docs/plugins/docs-category/eventin/
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use DateTime;
+use DateTimeZone;
+use Etn\Core\Event\Event_Model;
+
+use function Activitypub\esc_hashtag;
+
+/**
+ * ActivityPub Transformer for Events managed with Eventin.
+ *
+ * @since 1.0.0
+ */
+final class Eventin extends Event {
+
+	/**
+	 * Holds the EM_Event object.
+	 *
+	 * @var Event_Model
+	 */
+	protected $event_model;
+
+	/**
+	 * Extend the constructor, to also set the Event Model.
+	 *
+	 * This is a special class object form The Events Calendar which
+	 * has a lot of useful functions, we make use of our getter functions.
+	 *
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
+	 */
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->event_model = new Event_Model( $this->wp_object->ID );
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_start_time(): string {
+		return \gmdate( 'Y-m-d\TH:i:s\Z', strtotime( $this->event_model->get_start_datetime() ) );
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_end_time(): string {
+		return \gmdate( 'Y-m-d\TH:i:s\Z', strtotime( $this->event_model->get_end_datetime() ) );
+	}
+
+	/**
+	 * Get the timezone of the event.
+	 */
+	public function get_timezone(): string {
+		return $this->event_model->get_timezone();
+	}
+
+	/**
+	 * Get whether the event is online.
+	 *
+	 * @return bool
+	 */
+	public function get_is_online(): bool {
+		return 'online' === $this->event_model->__get( 'event_type' ) ? true : false;
+	}
+
+	/**
+	 * Maybe add online link to attachments.
+	 *
+	 * @return array
+	 */
+	public function get_attachment(): array {
+		$attachment = parent::get_attachment();
+
+		$location = (array) $this->event_model->__get( 'location' );
+		if ( array_key_exists( 'integration', $location ) && array_key_exists( $location['integration'], $location ) ) {
+			$online_link  = array(
+				'type'      => 'Link',
+				'mediaType' => 'text/html',
+				'name'      => $location[ $location['integration'] ],
+				'href'      => $location[ $location['integration'] ],
+			);
+			$attachment[] = $online_link;
+		}
+		return $attachment;
+	}
+
+	/**
+	 * Compose the events tags.
+	 */
+	public function get_tag() {
+		// The parent tag function also fetches the mentions.
+		$tags = parent::get_tag();
+
+		$post_tags       = \wp_get_post_terms( $this->wp_object->ID, 'etn_tags' );
+		$post_categories = \wp_get_post_terms( $this->wp_object->ID, 'etn_category' );
+
+		if ( ! is_wp_error( $post_tags ) && $post_tags ) {
+			foreach ( $post_tags as $term ) {
+				$tag    = array(
+					'type' => 'Hashtag',
+					'href' => \esc_url( \get_tag_link( $term->term_id ) ),
+					'name' => esc_hashtag( $term->name ),
+				);
+				$tags[] = $tag;
+			}
+		}
+
+		if ( ! is_wp_error( $post_categories ) && $post_categories ) {
+			foreach ( $post_categories as $term ) {
+				$tag    = array(
+					'type' => 'Hashtag',
+					'href' => \esc_url( \get_tag_link( $term->term_id ) ),
+					'name' => esc_hashtag( $term->name ),
+				);
+				$tags[] = $tag;
+			}
+		}
+
+		if ( empty( $tags ) ) {
+			return null;
+		}
+
+		return $tags;
+	}
+
+	/**
+	 * Get the location.
+	 *
+	 * @return ?Place
+	 */
+	public function get_location(): ?Place {
+		$location = (array) $this->event_model->__get( 'location' );
+
+		if ( ! array_key_exists( 'address', $location ) ) {
+			return null;
+		}
+
+		$place = new Place();
+
+		$address = $location['address'];
+
+		$place->set_name( $address );
+		$place->set_address( $address );
+		$place->set_sensitive( null );
+
+		return $place;
+	}
+}

includes/activitypub/transformer/class-events-manager.php

@@ -1,23 +1,24 @@
 <?php
-
 /**
  * ActivityPub Transformer for the plugin Very Simple Event List.
  *
- * @package activity-event-transformers
+ * @package Event_Bridge_For_ActivityPub
  * @license AGPL-3.0-or-later
  */
 
-use EM_Event;
-use Activitypub\Activity\Extended_Object\Event;
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
 use Activitypub\Activity\Extended_Object\Place;
-use Activitypub\Transformer\Post;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use DateTime;
+use DateTimeZone;
+use EM_Event;
 
 use function Activitypub\esc_hashtag;
 
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
 /**
  * ActivityPub Transformer for events from the WordPress plugin 'Events Manager'
  *
@@ -25,7 +26,7 @@ if ( ! defined( 'ABSPATH' ) ) {
  *
  * @since 1.0.0
  */
-class Events_Manager extends Post {
+final class Events_Manager extends Event_Transformer {
 
 	/**
 	 * Holds the EM_Event object.
@@ -35,94 +36,58 @@ class Events_Manager extends Post {
 	protected $em_event;
 
 	/**
-	 * Get transformer name.
+	 * Extend the constructor, to also set the Eventsmanager objects.
 	 *
-	 * Retrieve the transformers name.
+	 * This is a special class object form The Events Calendar which
+	 * has a lot of useful functions, we make use of our getter functions.
 	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget name.
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
 	 */
-	public function get_transformer_name() {
-
-		return 'activitypub-event-transformers/events-manager';
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->em_event = new EM_Event( $this->wp_object->ID, 'post_id' );
 	}
 
 	/**
-	 * Get transformer title.
+	 * Returns whether the even is online
 	 *
-	 * Retrieve the transformers label.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget title.
+	 * @return bool
 	 */
-	public function get_transformer_label() {
-
-		return 'Events Manager';
-	}
-
-	/**
-	 * Get supported post types.
-	 *
-	 * Retrieve the list of supported WordPress post types this transformer widget can handle.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return array Widget categories.
-	 */
-	public static function get_supported_post_types() {
-
-		return array();
-	}
-
-	/**
-	 * Returns the ActivityStreams 2.0 Object-Type for an Event.
-	 *
-	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event
-	 * @since 1.0.0
-	 * @return string The Event Object-Type.
-	 */
-	protected function get_type() {
-
-		return 'Event';
-	}
-
 	protected function get_is_online() {
-
 		return 'url' === $this->em_event->event_location_type;
 	}
 
 	/**
 	 * Get the event location.
 	 *
-	 * @param int $post_id The WordPress post ID.
 	 * @return array The Place.
 	 */
-	public function get_location() {
-
+	public function get_location(): ?Place {
 		if ( 'url' === $this->em_event->event_location_type ) {
 			return null;
 		}
 
-		$location    = new Place();
 		$em_location = $this->em_event->get_location();
 
+		if ( '' === $em_location->location_id ) {
+			return null;
+		}
+
+		$location = new Place();
 		$location->set_name( $em_location->location_name );
 
 		$address = array(
 			'type'            => 'PostalAddress',
 			'addressCountry'  => $em_location->location_country,
 			'addressLocality' => $em_location->location_town,
-			'streetAddress'   => $em_location->location_address,
+			'postalAddress'   => $em_location->location_address,
+			'postalCode'      => $em_location->location_postcode,
 			'name'            => $em_location->location_name,
 		);
 		if ( $em_location->location_state ) {
 			$address['addressRegion'] = $em_location->location_state;
 		}
-		if ( $em_location->location_postcode ) {
-			$address['postalCode'] = $em_location->location_postcode;
-		}
 
 		$location->set_address( $address );
 		return $location;
@@ -131,84 +96,70 @@ class Events_Manager extends Post {
 	/**
 	 * Get the end time from the events metadata.
 	 */
-	protected function get_end_time() {
-
+	public function get_end_time(): ?string {
 		return null;
 	}
 
 	/**
 	 * Get the end time from the events metadata.
 	 */
-	protected function get_start_time() {
-
+	public function get_start_time(): string {
 		$date_string     = $this->em_event->event_start_date;
 		$time_string     = $this->em_event->event_start_time;
 		$timezone_string = $this->em_event->event_timezone;
 
-		// Create a DateTime object with the given date, time, and timezone
+		// Create a DateTime object with the given date, time, and timezone.
 		$datetime = new DateTime( $date_string . ' ' . $time_string, new DateTimeZone( $timezone_string ) );
 
-		// Set the timezone for proper formatting
+		// Set the timezone for proper formatting.
 		$datetime->setTimezone( new DateTimeZone( 'UTC' ) );
 
-		// Format the DateTime object as 'Y-m-d\TH:i:s\Z'
+		// Format the DateTime object as 'Y-m-d\TH:i:s\Z'.
 		$formatted_date = $datetime->format( 'Y-m-d\TH:i:s\Z' );
 		return $formatted_date;
 	}
 
-	protected function get_maximum_attendee_capacity() {
-
+	/**
+	 * Returns the maximum attendee capacity.
+	 *
+	 * @return int
+	 */
+	public function get_maximum_attendee_capacity() {
 		return $this->em_event->event_spaces;
 	}
 
 	/**
-	 * @todo decide whether to include pending bookings or not!
+	 * Return the remaining attendee capacity
+	 *
+	 * @return int
 	 */
-	protected function get_remaining_attendee_capacity() {
-
-		$em_bookings                 = $this->em_event->get_bookings()->get_bookings();
-		$remaining_attendee_capacity = $this->em_event->event_spaces - count( $em_bookings->bookings );
+	public function get_remaining_attendee_capacity() {
+		$em_bookings_count           = $this->get_participant_count();
+		$remaining_attendee_capacity = $this->em_event->event_spaces - $em_bookings_count;
 		return $remaining_attendee_capacity;
 	}
 
-	protected function get_participant_count() {
-
+	/**
+	 * Returns the current participant count.
+	 *
+	 * @return int
+	 */
+	public function get_participant_count(): int {
 		$em_bookings = $this->em_event->get_bookings()->get_bookings();
 		return count( $em_bookings->bookings );
 	}
 
-	protected function get_content() {
-
-		return $this->wp_object->post_content;
-	}
-
-	protected function get_summary() {
-
-		if ( $this->em_event->post_excerpt ) {
-			$excerpt = $this->em_event->post_excerpt;
-		} else {
-			$excerpt = $this->get_content();
-		}
-		$address           = $this->em_event->get_location()->location_name;
-		$start_time        = strtotime( $this->get_start_time() );
-		$datetime_format   = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
-		$start_time_string = wp_date( $datetime_format, $start_time );
-		$summary           = "📍 {$address}\n📅 {$start_time_string}\n\n{$excerpt}";
-		return $summary;
-	}
-
-	// protected function get_join_mode() {
-	// return 'free';
-	// }
-
-	private function get_event_link_attachment() {
-
+	/**
+	 * Get the event link as an ActivityPub Link object, but as an associative array.
+	 *
+	 * @return array
+	 */
+	private function get_event_link_attachment(): array {
 		$event_link_url  = $this->em_event->event_location->data['url'];
 		$event_link_text = $this->em_event->event_location->data['text'];
 		return array(
 			'type'      => 'Link',
-			'name'      => 'Website',
-			// 'name' => $event_link_text,
+			'name'      => $event_link_text ? $event_link_text : 'Website',
 			'href'      => \esc_url( $event_link_url ),
 			'mediaType' => 'text/html',
 		);
@@ -218,7 +169,7 @@ class Events_Manager extends Post {
 	 * Overrides/extends the get_attachments function to also add the event Link.
 	 */
 	protected function get_attachment() {
-		// Get attachments via parent function
+		// Get attachments via parent function.
 		$attachments = parent::get_attachment();
 
 		// The first attachment is the featured image, make sure it is compatible with Mobilizon.
@@ -234,55 +185,9 @@ class Events_Manager extends Post {
 	}
 
 	/**
-	 * This function tries to map VS-Event categories to Mobilizon event categories.
-	 *
-	 * @return string $category
+	 * Compose the events tags.
 	 */
-	protected function get_category() {
-
-		$categories = $this->em_event->get_categories()->terms;
-
-		if ( empty( $categories ) ) {
-			return 'MEETING';
-		}
-
-		// Prepare an array to store all category information for comparison.
-		$category_info = array();
-
-		// Extract relevant category information (name, slug, description) from the categories array.
-		foreach ( $categories as $category ) {
-			$category_info[] = strtolower( $category->name );
-			$category_info[] = strtolower( $category->slug );
-			$category_info[] = strtolower( $category->description );
-		}
-
-		// Convert mobilizon categories to lowercase for case-insensitive comparison.
-		$mobilizon_categories = array_map( 'strtolower', Event::DEFAULT_EVENT_CATEGORIES );
-
-		// Initialize variables to track the best match.
-		$best_mobilizon_category_match = '';
-		$best_match_length             = 0;
-
-		// Check for the best match.
-		foreach ( $mobilizon_categories as $mobilizon_category ) {
-			foreach ( $category_info as $category ) {
-				foreach ( explode( '_', $mobilizon_category ) as $mobilizon_category_slice ) {
-					if ( stripos( $category, $mobilizon_category_slice ) !== false ) {
-						// Check if the current match is longer than the previous best match.
-						$current_match_legnth = strlen( $mobilizon_category_slice );
-						if ( $current_match_legnth > $best_match_length ) {
-							$best_mobilizon_category_match = $mobilizon_category;
-							$best_match_length             = $current_match_legnth;
-						}
-					}
-				}
-			}
-		}
-
-		return ( '' != $best_mobilizon_category_match ) ? strtoupper( $best_mobilizon_category_match ) : 'MEETING';
-	}
-
-	protected function get_tag() {
+	public function get_tag() {
 		// The parent tag function also fetches the mentions.
 		$tags = parent::get_tag();
 
@@ -301,25 +206,12 @@ class Events_Manager extends Post {
 		return $tags;
 	}
 
-	protected function get_name() {
-
+	/**
+	 * Get the events title/name.
+	 *
+	 * @return string
+	 */
+	protected function get_name(): string {
 		return $this->em_event->event_name;
 	}
-
-	/**
-	 * Transform the WordPress Object into an ActivityPub Object.
-	 *
-	 * @return Activitypub\Activity\Event
-	 */
-	public function to_object() {
-
-		$this->em_event     = new EM_Event( $this->wp_object->ID, 'post_id' );
-		$activitypub_object = new Event();
-
-		$activitypub_object = $this->transform_object_properties( $activitypub_object );
-
-		$activitypub_object->set_external_participation_url( $this->get_url() );
-
-		return $activitypub_object;
-	}
 }

includes/activitypub/transformer/class-gatherpress.php

@@ -1,41 +1,32 @@
 <?php
 /**
- * ActivityPub Transformer for the plugin Very Simple Event List.
+ * ActivityPub Transformer for the GatherPress event plugin.
  *
- * @package activity-event-transformers
+ * @package Event_Bridge_For_ActivityPub
  * @license AGPL-3.0-or-later
  */
 
-use Activitypub\Transformer\Post;
-use Activitypub\Model\Blog_user;
-use Activitypub\Activity\Extended_Object\Event;
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Event as Event_Object;
 use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
 use GatherPress\Core\Event as GatherPress_Event;
 
-use function Activitypub\get_rest_url_by_path;
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
 /**
  * ActivityPub Transformer for VS Event
  *
  * @since 1.0.0
  */
-class GatherPress extends Post {
-
-	/**
-	 * The target transformet ActivityPub Event object.
-	 *
-	 * @var Event
-	 */
-	protected $ap_object;
+final class GatherPress extends Event {
 
 	/**
 	 * The current GatherPress Event object.
 	 *
-	 * @var Event
+	 * @var GatherPress_Event
 	 */
 	protected $gp_event;
 
@@ -47,87 +38,49 @@ class GatherPress extends Post {
 	protected $gp_venue;
 
 	/**
-	 * Get transformer name.
+	 * Extend the constructor, to also set the GatherPress objects.
 	 *
-	 * Retrieve the transformers name.
+	 * This is a special class object form The Events Calendar which
+	 * has a lot of useful functions, we make use of our getter functions.
 	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget name.
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
 	 */
-	public function get_transformer_name() {
-
-		return 'gatherpress/gp-event';
-	}
-
-	/**
-	 * Get transformer title.
-	 *
-	 * Retrieve the transformers label.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget title.
-	 */
-	public function get_transformer_label() {
-
-		return 'GatherPress Event';
-	}
-
-	/**
-	 * Get supported post types.
-	 *
-	 * Retrieve the list of supported WordPress post types this transformer widget can handle.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return array Widget categories.
-	 */
-	public static function get_supported_post_types() {
-
-		return array( GatherPress_Event::POST_TYPE );
-	}
-
-	/**
-	 * Returns the ActivityStreams 2.0 Object-Type for an Event.
-	 *
-	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event
-	 * @since 1.0.0
-	 * @return string The Event Object-Type.
-	 */
-	protected function get_type() {
-
-		return 'Event';
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->gp_event = new GatherPress_Event( $this->wp_object->ID );
+		$this->gp_venue = $this->gp_event->get_venue_information();
 	}
 
 	/**
 	 * Get the event location.
 	 *
-	 * @return array The Place.
+	 * @return Place|null The place objector null if not place set.
 	 */
-	public function get_location() {
-
+	public function get_location(): ?Place {
 		$address = $this->gp_venue['full_address'];
+		if ( $address ) {
 			$place = new Place();
 			$place->set_type( 'Place' );
 			$place->set_name( $address );
 			$place->set_address( $address );
 			return $place;
+		} else {
+			return null;
+		}
 	}
 
 	/**
 	 * Get the end time from the event object.
 	 */
-	protected function get_end_time() {
-
+	public function get_end_time(): ?string {
 		return $this->gp_event->get_datetime_end( 'Y-m-d\TH:i:s\Z' );
 	}
 
 	/**
 	 * Get the end time from the event object.
 	 */
-	protected function get_start_time() {
-
+	public function get_start_time(): string {
 		return $this->gp_event->get_datetime_start( 'Y-m-d\TH:i:s\Z' );
 	}
 
@@ -150,8 +103,7 @@ class GatherPress extends Post {
 	/**
 	 * Overrides/extends the get_attachments function to also add the event Link.
 	 */
-	protected function get_attachment() {
-
+	protected function get_attachment(): array {
 		$attachments = parent::get_attachment();
 		if ( count( $attachments ) ) {
 			$attachments[0]['type'] = 'Document';
@@ -165,87 +117,38 @@ class GatherPress extends Post {
 	}
 
 	/**
-	 * TODO:
+	 * Prevents gatherpress blocks from being rendered for the content.
 	 *
-	 * @return string $category
+	 * @param mixed $block_content The blocks content.
+	 * @param mixed $block         The block.
 	 */
-	protected function get_category() {
+	public static function filter_gatherpress_blocks( $block_content, $block ) {
+		// Check if the block name starts with 'gatherpress'.
+		if ( isset( $block['blockName'] ) && 0 === strpos( $block['blockName'], 'gatherpress/' ) ) {
+			return ''; // Skip rendering this block.
+		}
 
-		return 'MEETING';
+		return $block_content; // Return the content for other blocks.
 	}
 
 	/**
-	 * Returns the User-URL of the Author of the Post.
+	 * Apply the filter for preventing the rendering off gatherpress blocks just in time.
 	 *
-	 * If `single_user` mode is enabled, the URL of the Blog-User is returned.
-	 *
-	 * @return string The User-URL.
+	 * @return Event_Object
 	 */
-	protected function get_attributed_to() {
-
-		$user = new Blog_User();
-		return $user->get_url();
+	public function to_object(): Event_Object {
+		add_filter( 'render_block', array( self::class, 'filter_gatherpress_blocks' ), 10, 2 );
+		$activitypub_object = parent::to_object();
+		remove_filter( 'render_block', array( self::class, 'filter_gatherpress_blocks' ) );
+		return $activitypub_object;
 	}
 
 	/**
-	 * Create a custom summary.
+	 * Determine whether the event is online.
 	 *
-	 * It contains also the most important meta-information. The summary is often used when the
-	 * ActivityPub object type 'Event' is not supported, e.g. in Mastodon.
-	 *
-	 * @return string $summary The custom event summary.
+	 * @return bool
 	 */
-	public function get_summary() {
-
-		if ( $this->wp_object->excerpt ) {
-			$excerpt = $this->wp_object->post_excerpt;
-		} elseif ( get_post_meta( $this->wp_object->ID, 'event-summary', true ) ) {
-			$excerpt = get_post_meta( $this->wp_object->ID, 'event-summary', true );
-		} else {
-			$excerpt = $this->get_content();
-		}
-
-		$address           = get_post_meta( $this->wp_object->ID, 'event-location', true );
-		$start_time        = get_post_meta( $this->wp_object->ID, 'event-start-date', true );
-		$datetime_format   = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
-		$start_time_string = wp_date( $datetime_format, $start_time );
-		$summary           = "📍 {$address}\n📅 {$start_time_string}\n\n{$excerpt}";
-		return $summary;
-	}
-
-	/**
-	 * Transform the WordPress Object into an ActivityPub Object.
-	 *
-	 * @return Activitypub\Activity\Event
-	 */
-	public function to_object() {
-
-		$this->ap_object = new Event();
-		$this->gp_event  = new GatherPress_Event( $this->wp_object->ID );
-		$this->gp_venue  = $this->gp_event->get_venue_information();
-
-		$this->ap_object = parent::to_object();
-
-		$this->ap_object->set_comments_enabled( 'open' === $this->wp_object->comment_status ? true : false );
-
-		$this->ap_object->set_external_participation_url( $this->get_url() );
-
-		$online_event_link = $this->gp_event->maybe_get_online_event_link();
-
-		if ( $online_event_link ) {
-			$this->ap_object->set_is_online( true );
-		} else {
-			$this->ap_object->set_is_online( false );
-		}
-
-		$this->ap_object->set_status( 'CONFIRMED' );
-
-		$this->ap_object->set_name( get_the_title( $this->wp_object->ID ) );
-
-		$this->ap_object->set_actor( get_rest_url_by_path( 'application' ) );
-		$this->ap_object->set_to( array( 'https://www.w3.org/ns/activitystreams#Public' ) );
-
-		$this->ap_object->set_location();
-		return $this->ap_object;
+	public function get_is_online(): bool {
+		return $this->gp_event->maybe_get_online_event_link() ? true : false;
 	}
 }

includes/activitypub/transformer/class-modern-events-calendar-lite.php

@@ -0,0 +1,122 @@
+<?php
+/**
+ * ActivityPub Tribe Transformer
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+
+use MEC;
+use MEC\Events\Event as MEC_Event;
+use MEC_main;
+
+/**
+ * ActivityPub Tribe Transformer
+ *
+ * @since 1.0.0
+ */
+final class Modern_Events_Calendar_Lite extends Event {
+	/**
+	 * The MEC Event object.
+	 *
+	 * @var MEC_Event|null
+	 */
+	protected $mec_event;
+
+	/**
+	 * The MEC main instance.
+	 *
+	 * @var MEC_main|null
+	 */
+	protected $mec_main;
+
+
+	/**
+	 * Extend the constructor, to also set the tribe object.
+	 *
+	 * This is a special class object form The Events Calendar which
+	 * has a lot of useful functions, we make use of our getter functions.
+	 *
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
+	 */
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->mec_main  = MEC::getInstance( 'app.libraries.main' );
+		$this->mec_event = new MEC_Event( $wp_object );
+	}
+
+	/**
+	 * Retrieves the content without the plugins rendered shortcodes.
+	 */
+	public function get_content(): string {
+		$content = wpautop( $this->wp_object->post_content );
+		return $content;
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_start_time(): string {
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $this->mec_event->get_datetime()['start']['timestamp'] );
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_end_time(): ?string {
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $this->mec_event->get_datetime()['end']['timestamp'] );
+	}
+
+	/**
+	 * Get the location.
+	 */
+	public function get_location(): ?Place {
+		$location_id = $this->mec_main->get_master_location_id( $this->mec_event->ID );
+
+		if ( ! $location_id ) {
+			return null;
+		}
+
+		$data = $this->mec_main->get_location_data( $location_id );
+
+		$location = new Place();
+		$location->set_sensitive( null );
+
+		if ( ! empty( $data['address'] ) ) {
+			$location->set_address( $data['address'] );
+		}
+		if ( ! empty( $data['name'] ) ) {
+			$location->set_name( $data['name'] );
+		}
+		if ( ! empty( $data['longitude'] ) ) {
+			$location->set_longitude( $data['longitude'] );
+		}
+		if ( ! empty( $data['latitude'] ) ) {
+			$location->set_latitude( $data['latitude'] );
+		}
+
+		return $location;
+	}
+
+	/**
+	 * Get the location.
+	 */
+	public function get_timezone(): string {
+		$timezone = get_post_meta( $this->wp_object->ID, 'mec_timezone', true );
+
+		if ( 'global' === $timezone ) {
+			return parent::get_timezone();
+		}
+
+		return $timezone;
+	}
+}

includes/activitypub/transformer/class-the-events-calendar.php

@@ -0,0 +1,190 @@
+<?php
+/**
+ * ActivityPub Tribe Transformer
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use WP_Post;
+
+use function Activitypub\esc_hashtag;
+
+/**
+ * ActivityPub Tribe Transformer
+ *
+ * @since 1.0.0
+ */
+final class The_Events_Calendar extends Event {
+
+	/**
+	 * The Tribe Event object.
+	 *
+	 * @var array|WP_Post|null
+	 */
+	protected $tribe_event;
+
+	/**
+	 * Extend the constructor, to also set the tribe object.
+	 *
+	 * This is a special class object form The Events Calendar which
+	 * has a lot of useful functions, we make use of our getter functions.
+	 *
+	 * @param WP_Post $wp_object The WordPress object.
+	 * @param string  $wp_taxonomy The taxonomy slug of the event post type.
+	 */
+	public function __construct( $wp_object, $wp_taxonomy ) {
+		parent::__construct( $wp_object, $wp_taxonomy );
+		$this->tribe_event = \tribe_get_event( $wp_object );
+	}
+
+	/**
+	 * Get the tags, including also the set categories from The Events Calendar.
+	 *
+	 * @return ?array The array if tags,
+	 */
+	public function get_tag(): ?array {
+		$tags         = array();
+		$category_ids = tribe_get_event_cat_ids();
+		if ( $category_ids ) {
+			foreach ( $category_ids as $category_id ) {
+				$term   = \get_term( $category_id );
+				$tag    = array(
+					'type' => 'Hashtag',
+					'href' => \esc_url( \get_term_link( $term ) ),
+					'name' => esc_hashtag( $term->name ),
+				);
+				$tags[] = $tag;
+			}
+		}
+		$tags = array_merge( $tags, parent::get_tag() );
+
+		return $tags;
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_end_time(): ?string {
+		if ( empty( $this->tribe_event->end_date ) ) {
+			return null;
+		}
+		$date = date_create( $this->tribe_event->end_date, wp_timezone() );
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $date->getTimestamp() );
+	}
+
+	/**
+	 * Get the end time from the event object.
+	 */
+	public function get_start_time(): string {
+		$date = date_create( $this->tribe_event->start_date, wp_timezone() );
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $date->getTimestamp() );
+	}
+
+	/**
+	 * Get status of the tribe event
+	 *
+	 * @return string status of the event
+	 */
+	public function get_status(): ?string {
+		if ( 'canceled' === $this->tribe_event->event_status ) {
+			return 'CANCELLED';
+		}
+		if ( 'postponed' === $this->tribe_event->event_status ) {
+			return 'CANCELLED'; // This will be reflected in the cancelled reason.
+		}
+		return 'CONFIRMED';
+	}
+
+
+	/**
+	 * Check if the comments are enabled for the current event.
+	 */
+	public function get_comments_enabled(): bool {
+		return ( 'open' === $this->tribe_event->comment_status ) ? true : false;
+	}
+
+	/**
+	 * Check if the event is an online event.
+	 */
+	public function get_is_online(): bool {
+		return false;
+	}
+
+	/**
+	 * Get the event location.
+	 *
+	 * @return ?Place The place/venue if one is set.
+	 */
+	public function get_location(): ?Place {
+		// Get short handle for the venues.
+		$venues = $this->tribe_event->venues;
+
+		// Get first venue. We currently only support a single venue.
+		if ( $venues instanceof \Tribe\Events\Collections\Lazy_Post_Collection ) {
+			$venue = $venues->first();
+		} elseif ( empty( $this->wp_object->venues ) || ! empty( $this->wp_object->venues[0] ) ) {
+			return null;
+		} else {
+			$venue = $venues[0];
+		}
+
+		if ( ! $venue ) {
+			return null;
+		}
+
+		// Set the address.
+		$address = array();
+
+		if ( ! empty( $venue->country ) ) {
+			$address['addressCountry'] = $venue->country;
+		}
+
+		if ( ! empty( $venue->city ) ) {
+			$address['addressLocality'] = $venue->city;
+		}
+
+		if ( ! empty( $venue->province ) ) {
+			$address['addressRegion'] = $venue->province;
+		}
+
+		if ( ! empty( $venue->zip ) ) {
+			$address['postalCode'] = $venue->zip;
+		}
+
+		if ( ! empty( $venue->address ) ) {
+			$address['streetAddress'] = $venue->address;
+		}
+		if ( ! empty( $venue->post_title ) ) {
+			$address['name'] = $venue->post_title;
+		}
+		$address['type'] = 'PostalAddress';
+
+		$location = new Place();
+		if ( count( $address ) > 1 ) {
+			$location->set_address( $address );
+		} else {
+			$location->set_address( $venue->post_title );
+		}
+		$location->set_id( $venue->ID );
+		$location->set_name( $venue->post_title );
+
+		return $location;
+	}
+
+	/**
+	 * Get the timezone of the event.
+	 *
+	 * @return string  The timezone string of the site.
+	 */
+	public function get_timezone(): string {
+		return $this->tribe_event->timezone;
+	}
+}

includes/activitypub/transformer/class-tribe.php

@@ -1,189 +0,0 @@
-<?php
-
-/**
- * ActivityPub Tribe Transformer
- *
- * @package activity-event-transformers
- * @license AGPL-3.0-or-later
- */
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
-use Activitypub\Transformer\Post;
-use Activitypub\Activity\Extended_Object\Event;
-use Activitypub\Activity\Extended_Object\Place;
-
-/**
- * ActivityPub Tribe Transformer
- *
- * @since 1.0.0
- */
-class Tribe extends Post {
-
-	/**
-	 * The Tribe Event object.
-	 *
-	 * @var WP_Post
-	 */
-	protected $tribe_event;
-
-	// /**
-	// * resolve the tribe metadata in the setter of wp_post.
-	// *
-	// * @param WP_Post $wp_post The WP_Post object.
-	// * @return void
-	// */
-	// public function set_wp_post( WP_Post $wp_post ) {
-	// parent::set_wp_post( $wp_post );
-	// $this->tribe_event = tribe_get_event( $wp_post->ID );
-	// }
-
-	/**
-	 * Get widget name.
-	 *
-	 * Retrieve oEmbed widget name.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget name.
-	 */
-	public function get_name() {
-
-		return 'activitypub-event-transformers/tribe';
-	}
-
-	/**
-	 * Get widget title.
-	 *
-	 * Retrieve Transformer title.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget title.
-	 */
-	public function get_label() {
-
-		return 'The Events Calendar';
-	}
-
-	/**
-	 * Returns the ActivityStreams 2.0 Object-Type for an Event.
-	 *
-	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event
-	 *
-	 * @return string The Event Object-Type.
-	 */
-	protected function get_object_type() {
-
-		return 'Event';
-	}
-
-	/**
-	 * Get supported post types.
-	 *
-	 * Retrieve the list of supported WordPress post types this transformer widget can handle.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return array Widget categories.
-	 */
-	public static function get_supported_post_types() {
-
-		return array( 'tribe_events' );
-	}
-
-	/**
-	 * Get tribe category of wp_post
-	 *
-	 * @return string|null tribe category if it exists
-	 */
-	public function get_tribe_category() {
-		// todo make it possible that one event can have multiple categories?
-
-		// using cat_slugs isn't 100% nice way to do this, don't know if it's a good idea
-		$categories = tribe_get_event_cat_slugs( $this->wp_object->ID );
-
-		if ( count( $categories ) === 0 ) {
-			return null;
-		}
-
-		return $categories[0];
-	}
-
-	/**
-	 * Get status of the tribe event
-	 *
-	 * @return string status of the event
-	 */
-	public function get_tribe_status() {
-
-		if ( 'canceled' === $this->tribe_event->event_status ) {
-			return 'CANCELLED';
-		}
-		if ( 'postponed' === $this->tribe_event->event_status ) {
-			return 'CANCELLED'; // this will be reflected in the cancelled reason
-		}
-		if ( '' === $this->tribe_event->event_status ) {
-			return 'CONFIRMED';
-		}
-
-		return new WP_Error( 'invalid event_status value', __( 'invalid event_status', 'activitypub' ), array( 'status' => 404 ) );
-	}
-
-	/**
-	 * Returns the content for the ActivityPub Item with
-	 *
-	 * The content will be generated based on the user settings.
-	 *
-	 * @return string The content.
-	 */
-	protected function get_content() {
-
-		$content = parent::get_content();
-		// todo remove link at the end of the content
-
-		// todo add organizer
-		// $this->tribe_event->organizers[0]
-
-		// todo add Canclled reason in the content (maybe at the end)
-
-		return $content;
-	}
-
-	/**
-	 * Get the event location.
-	 *
-	 * @param int $post_id The WordPress post ID.
-	 * @returns array The Place.
-	 */
-	public function get_event_location() {
-		/*
-				'post_title' => 'testvenue',
-				'post_name' => 'testvenue',
-				'guid' => 'http://localhost/venue/testvenue/',
-				'post_type' => 'tribe_venue',
-				'address' => 'testaddr',
-				'country' => 'Austria',
-				'city' => 'testcity',
-				'state_province' => 'testprovince',
-				'state' => '',
-				'province' => 'testprovince',
-				'zip' => '8000',
-				'phone' => '+4312343',
-				'permalink' => 'http://localhost/venue/testvenue/',
-				'directions_link' => 'https://maps.google.com/maps?f=q&#038;source=s_q&#038;hl=en&#038;geocode=&#038;q=testaddr+testcity+testprovince+8000+Austria',
-				'website' => 'https://test.at',
-		 */
-		$venue = $this->tribe_event->venues[0];
-		return ( new Place() )
-			->set_type( 'Place' )
-			->set_name( $venue->post_name )
-			->set_address(
-				$venue->address . "\n" .
-							$venue->zip . ', ' . $venue->city . "\n" .
-							$venue->country
-			); // todo add checks that everything exists here (lol)
-	}
-}

includes/activitypub/transformer/class-vs-event-list.php

@@ -0,0 +1,113 @@
+<?php
+/**
+ * ActivityPub Transformer for the plugin Very Simple Event List.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+
+/**
+ * ActivityPub Transformer for VS Event.
+ *
+ * This transformer tries a different principle: The setters are chainable.
+ *
+ * @since 1.0.0
+ */
+final class VS_Event_List extends Event_Transformer {
+
+	/**
+	 * Get the event location.
+	 *
+	 * @return Place The Place.
+	 */
+	public function get_location(): ?Place {
+		$address = get_post_meta( $this->wp_object->ID, 'event-location', true );
+		if ( $address ) {
+			$place = new Place();
+			$place->set_type( 'Place' );
+			$place->set_name( $address );
+			$place->set_address( $address );
+			return $place;
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Get the end time from the events metadata.
+	 */
+	public function get_end_time(): ?string {
+		if ( 'yes' === get_post_meta( $this->wp_object->ID, 'event-hide-end-time', true ) ) {
+			return null;
+		}
+		$end_time = get_post_meta( $this->wp_object->ID, 'event-date', true );
+		if ( is_null( $end_time ) || empty( $end_time ) || 'no' === $end_time ) {
+			return null;
+		}
+		return $end_time ? \gmdate( 'Y-m-d\TH:i:s\Z', $end_time ) : null;
+	}
+
+	/**
+	 * Get the end time from the events metadata.
+	 */
+	public function get_start_time(): string {
+		$start_time = get_post_meta( $this->wp_object->ID, 'event-start-date', true );
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $start_time );
+	}
+
+	/**
+	 * Get the event link from the events metadata.
+	 *
+	 * @return ?array Associated array of an ActivityStreams Link object with the events URL.
+	 */
+	private function get_event_link(): ?array {
+		$event_link       = get_post_meta( $this->wp_object->ID, 'event-link', true );
+		$event_link_label = get_post_meta( $this->wp_object->ID, 'event-link-label', true ) ?? 'Event Link';
+		if ( $event_link ) {
+			return array(
+				'type'      => 'Link',
+				'name'      => $event_link_label,
+				'href'      => \esc_url( $event_link ),
+				'mediaType' => 'text/html',
+			);
+		}
+		return null;
+	}
+
+	/**
+	 * Overrides/extends the get_attachments function to also add the event Link.
+	 */
+	protected function get_attachment(): ?array {
+		$attachments = parent::get_attachment();
+		if ( count( $attachments ) ) {
+			$attachments[0]['type'] = 'Document';
+			$attachments[0]['name'] = 'Banner';
+		}
+		$event_link = $this->get_event_link();
+		if ( $event_link ) {
+			$attachments[] = $event_link;
+		}
+		return $attachments;
+	}
+
+	/**
+	 * Retrieves the excerpt text (may be HTML). Used for constructing the summary.
+	 *
+	 * @return ?string
+	 */
+	protected function retrieve_excerpt(): ?string {
+		if ( get_post_meta( $this->wp_object->ID, 'event-summary', true ) ) {
+			return get_post_meta( $this->wp_object->ID, 'event-summary', true );
+		} else {
+			return parent::retrieve_excerpt();
+		}
+	}
+}

includes/activitypub/transformer/class-vs-event.php

@@ -1,321 +0,0 @@
-<?php
-
-/**
- * ActivityPub Transformer for the plugin Very Simple Event List.
- *
- * @package activity-event-transformers
- * @license AGPL-3.0-or-later
- */
-
-use Activitypub\Transformer\Post;
-use Activitypub\Model\Blog_user;
-use Activitypub\Activity\Extended_Object\Event;
-use Activitypub\Activity\Extended_Object\Place;
-
-use function Activitypub\get_rest_url_by_path;
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
-/**
- * ActivityPub Transformer for VS Event
- *
- * @since 1.0.0
- */
-class VS_Event extends Post {
-
-	/**
-	 * The target transformet ActivityPub Event object.
-	 *
-	 * @var Event
-	 */
-	protected $ap_object;
-
-	/**
-	 * Get transformer name.
-	 *
-	 * Retrieve the transformers name.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget name.
-	 */
-	public function get_transformer_name() {
-
-		return 'activitypub-event-transformers/vs-event';
-	}
-
-	/**
-	 * Get transformer title.
-	 *
-	 * Retrieve the transformers label.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return string Widget title.
-	 */
-	public function get_transformer_label() {
-
-		return 'VS Event';
-	}
-
-	/**
-	 * Get supported post types.
-	 *
-	 * Retrieve the list of supported WordPress post types this transformer widget can handle.
-	 *
-	 * @since 1.0.0
-	 * @access public
-	 * @return array Widget categories.
-	 */
-	public static function get_supported_post_types() {
-
-		return array( 'event' );
-	}
-
-	/**
-	 * Returns the ActivityStreams 2.0 Object-Type for an Event.
-	 *
-	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event
-	 * @since 1.0.0
-	 * @return string The Event Object-Type.
-	 */
-	protected function get_type() {
-
-		return 'Event';
-	}
-
-	/**
-	 * Get the event location.
-	 *
-	 * @param int $post_id The WordPress post ID.
-	 * @return array The Place.
-	 */
-	public function get_location() {
-
-		$address = get_post_meta( $this->wp_object->ID, 'event-location', true );
-		$place   = new Place();
-		$place->set_type( 'Place' );
-		$place->set_name( $address );
-		$place->set_address( $address );
-		return $place;
-	}
-
-	/**
-	 * Get the end time from the events metadata.
-	 */
-	protected function get_end_time() {
-
-		$end_time = get_post_meta( $this->wp_object->ID, 'event-date', true );
-		return \gmdate( 'Y-m-d\TH:i:s\Z', $end_time );
-	}
-
-	/**
-	 * Get the end time from the events metadata.
-	 */
-	protected function get_start_time() {
-
-		$start_time = get_post_meta( $this->wp_object->ID, 'event-start-date', true );
-		return \gmdate( 'Y-m-d\TH:i:s\Z', $start_time );
-	}
-
-	/**
-	 * Get the event link from the events metadata.
-	 */
-	private function get_event_link() {
-
-		$event_link = get_post_meta( $this->wp_object->ID, 'event-link', true );
-		if ( $event_link ) {
-			return array(
-				'type'      => 'Link',
-				'name'      => 'Website',
-				'href'      => \esc_url( $event_link ),
-				'mediaType' => 'text/html',
-			);
-		}
-	}
-
-	/**
-	 * Overrides/extends the get_attachments function to also add the event Link.
-	 */
-	protected function get_attachment() {
-
-		$attachments = parent::get_attachment();
-		if ( count( $attachments ) ) {
-			$attachments[0]['type'] = 'Document';
-			$attachments[0]['name'] = 'Banner';
-		}
-		$event_link = $this->get_event_link();
-		if ( $event_link ) {
-			$attachments[] = $this->get_event_link();
-		}
-		return $attachments;
-	}
-
-	/**
-	 * This function tries to map VS-Event categories to Mobilizon event categories.
-	 *
-	 * @return string $category
-	 */
-	protected function get_category() {
-
-		$post_categories = wp_get_post_terms( $this->wp_object->ID, 'event_cat' );
-
-		if ( empty( $post_categories ) ) {
-			return 'MEETING';
-		}
-
-		// Prepare an array to store all category information for comparison.
-		$category_info = array();
-
-		// Extract relevant category information (name, slug, description) from the categories array.
-		foreach ( $post_categories as $category ) {
-			$category_info[] = strtolower( $category->name );
-			$category_info[] = strtolower( $category->slug );
-			$category_info[] = strtolower( $category->description );
-		}
-
-		// Convert mobilizon categories to lowercase for case-insensitive comparison.
-		$mobilizon_categories = array_map( 'strtolower', Event::DEFAULT_EVENT_CATEGORIES );
-
-		// Initialize variables to track the best match.
-		$best_mobilizon_category_match = '';
-		$best_match_length             = 0;
-
-		// Check for the best match.
-		foreach ( $mobilizon_categories as $mobilizon_category ) {
-			foreach ( $category_info as $category ) {
-				foreach ( explode( '_', $mobilizon_category ) as $mobilizon_category_slice ) {
-					if ( stripos( $category, $mobilizon_category_slice ) !== false ) {
-						// Check if the current match is longer than the previous best match.
-						$current_match_legnth = strlen( $mobilizon_category_slice );
-						if ( $current_match_legnth > $best_match_length ) {
-							$best_mobilizon_category_match = $mobilizon_category;
-							$best_match_length             = $current_match_legnth;
-						}
-					}
-				}
-			}
-		}
-
-		return ( '' != $best_mobilizon_category_match ) ? strtoupper( $best_mobilizon_category_match ) : 'MEETING';
-	}
-
-	/**
-	 * Returns the User-URL of the Author of the Post.
-	 *
-	 * If `single_user` mode is enabled, the URL of the Blog-User is returned.
-	 *
-	 * @return string The User-URL.
-	 */
-	protected function get_attributed_to() {
-
-		$user = new Blog_User();
-		return $user->get_url();
-	}
-
-	/**
-	 * Create a custom summary.
-	 *
-	 * It contains also the most important meta-information. The summary is often used when the
-	 * ActivityPub object type 'Event' is not supported, e.g. in Mastodon.
-	 *
-	 * @return string $summary The custom event summary.
-	 */
-	public function get_summary() {
-
-		if ( $this->wp_object->excerpt ) {
-			$excerpt = $this->wp_object->post_excerpt;
-		} elseif ( get_post_meta( $this->wp_object->ID, 'event-summary', true ) ) {
-			$excerpt = get_post_meta( $this->wp_object->ID, 'event-summary', true );
-		} else {
-			$excerpt = $this->get_content();
-		}
-
-		$address           = get_post_meta( $this->wp_object->ID, 'event-location', true );
-		$start_time        = get_post_meta( $this->wp_object->ID, 'event-start-date', true );
-		$datetime_format   = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
-		$start_time_string = wp_date( $datetime_format, $start_time );
-		$summary           = "📍 {$address}\n📅 {$start_time_string}\n\n{$excerpt}";
-		return $summary;
-	}
-
-	/**
-	 * Generic setter.
-	 *
-	 * @param string $key   The key to set.
-	 * @param string $value The value to set.
-	 *
-	 * @return mixed The value.
-	 */
-	public function set( $key, $value ) {
-
-		if ( ! $this->ap_object->has( $key ) ) {
-			return new WP_Error( 'invalid_key', __( 'Invalid key', 'activitypub' ), array( 'status' => 404 ) );
-		}
-
-		$setter_function = 'set_' . $key;
-		$getter_function = 'get_' . $key;
-
-		if ( in_array( $getter_function, get_class_methods( $this ) ) ) {
-			$this->ap_object->$setter_function( $this->$getter_function() );
-		} else {
-			$this->ap_object->$setter_function( $value );
-		}
-
-		return $this;
-	}
-
-	/**
-	 * Magic function to implement setter
-	 *
-	 * @param string $method The method name.
-	 * @param string $params The method params.
-	 *
-	 * @return void
-	 */
-	public function __call( $method, $params ) {
-
-		$var = \strtolower( \substr( $method, 4 ) );
-
-		if ( \strncasecmp( $method, 'set', 3 ) === 0 ) {
-			return $this->set( $var, $params[0] );
-		}
-
-		// when do we need: call_user_func( array( $activitypub_object, $setter ), $value );
-
-		return $this;
-	}
-
-	/**
-	 * Transform the WordPress Object into an ActivityPub Object.
-	 *
-	 * @return Activitypub\Activity\Event
-	 */
-	public function to_object() {
-
-		$this->ap_object = new Event();
-
-		$this
-			->set_content()
-			->set_content_map()
-			->set_attributed_to()
-			->set_published()
-			->set_start_time()
-			->set_end_time()
-			->set_type()
-			->set_category()
-			->set_attachment()
-			->set_comments_enabled( true )
-			->set_external_participation_url( $this->get_url() )
-			->set_status( 'CONFIRMED' )
-			->set_name( get_the_title( $this->wp_object->ID ) )
-			->set_is_online( false )
-			->set_in_language( $this->get_locale() )
-			->set_actor( get_rest_url_by_path( 'application' ) )
-			->set_to( array( 'https://www.w3.org/ns/activitystreams#Public' ) )
-			->set_location();
-		return $this->ap_object;
-	}
-}

includes/activitypub/transformer/class-wp-event-manager.php

@@ -0,0 +1,140 @@
+<?php
+/**
+ * ActivityPub Transformer for the plugin Very Simple Event List.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Place;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use DateTime;
+
+/**
+ * ActivityPub Transformer for events from the WordPress plugin 'Events Manager'
+ *
+ * @see https://wordpress.org/plugins/events-manager/
+ *
+ * @since 1.0.0
+ */
+final class WP_Event_Manager extends Event_Transformer {
+	/**
+	 * Returns whether the even is online
+	 *
+	 * @return bool
+	 */
+	protected function get_is_online() {
+		$is_online_text = get_post_meta( $this->wp_object->ID, '_event_online', true );
+		$is_online      = false;
+		// Radio buttons.
+		if ( 'yes' === $is_online_text ) {
+			$is_online = true;
+		}
+		// Checkbox.
+		if ( '1' === $is_online_text ) {
+			$is_online = true;
+		}
+		return $is_online;
+	}
+
+	/**
+	 * Get the event location.
+	 *
+	 * @return array The Place.
+	 */
+	public function get_location(): ?Place {
+		$location_name = get_post_meta( $this->wp_object->ID, '_event_location', true );
+
+		if ( $location_name ) {
+			$location = new Place();
+			$location->set_name( $location_name );
+			$location->set_sensitive( null );
+			$location->set_address( $location_name );
+
+			return $location;
+		}
+		return null;
+	}
+
+	/**
+	 * Get the end time from the events metadata.
+	 *
+	 * @return ?string The events end-datetime if is set, null otherwise.
+	 */
+	public function get_end_time(): ?string {
+		$end_date = get_post_meta( $this->wp_object->ID, '_event_end_date', true );
+		if ( $end_date ) {
+			$end_datetime = new DateTime( $end_date );
+			return \gmdate( 'Y-m-d\TH:i:s\Z', $end_datetime->getTimestamp() );
+		}
+		return null;
+	}
+
+	/**
+	 * Get the end time from the events metadata.
+	 */
+	public function get_start_time(): string {
+		$start_date = get_post_meta( $this->wp_object->ID, '_event_start_date', true );
+		if ( ! is_numeric( $start_date ) ) {
+			$start_datetime  = new DateTime( $start_date );
+			$start_timestamp = $start_datetime->getTimestamp();
+		} else {
+			$start_timestamp = (int) $start_date;
+		}
+
+		return \gmdate( 'Y-m-d\TH:i:s\Z', $start_timestamp );
+	}
+
+	/**
+	 * Get the event link as an ActivityPub Link object, but as an associative array.
+	 *
+	 * @return ?array
+	 */
+	private function get_event_link_attachment(): ?array {
+		$event_link_url = get_post_meta( $this->wp_object->ID, '_event_video_url', true );
+
+		if ( str_starts_with( $event_link_url, 'http' ) ) {
+			return array(
+				'type'      => 'Link',
+				'name'      => \esc_html__( 'Video URL', 'event-bridge-for-activitypub' ),
+				'href'      => \esc_url( $event_link_url ),
+				'mediaType' => 'text/html',
+			);
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Overrides/extends the get_attachments function to also add the event Link.
+	 */
+	protected function get_attachment() {
+		// Get attachments via parent function.
+		$attachments = parent::get_attachment();
+
+		// The first attachment is the featured image, make sure it is compatible with Mobilizon.
+		if ( count( $attachments ) ) {
+			$attachments[0]['type'] = 'Document';
+			$attachments[0]['name'] = 'Banner';
+		}
+
+		if ( $this->get_event_link_attachment() ) {
+			$attachments[] = $this->get_event_link_attachment();
+		}
+		return $attachments;
+	}
+
+	/**
+	 * Get the events title/name.
+	 *
+	 * @return string
+	 */
+	protected function get_name(): string {
+		return $this->wp_object->post_title;
+	}
+}

includes/admin/class-event-plugin-admin-notices.php

@@ -0,0 +1,103 @@
+<?php
+/**
+ * Class responsible for Event Plugin related admin notices.
+ *
+ * Notices for guiding to proper configuration of ActivityPub with event plugins.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Admin;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+
+/**
+ * Class responsible for Event Plugin related admin notices.
+ *
+ * Notices for guiding to proper configuration of ActivityPub with event plugins.
+ *
+ * @since 1.0.0
+ */
+class Event_Plugin_Admin_Notices {
+	/**
+	 * Information about the event plugin.
+	 *
+	 * @var Event_Plugin
+	 */
+	protected $event_plugin;
+
+	/**
+	 * Adds admin notices to an active supported event plugin.
+	 *
+	 * @param Event_Plugin $event_plugin Class that has implements functions to handle a certain supported activate event plugin.
+	 */
+	public function __construct( $event_plugin ) {
+		$this->event_plugin = $event_plugin;
+		if ( $this->event_post_type_is_not_activitypub_enabled() ) {
+			add_action( 'admin_notices', array( $this, 'admin_notice_activitypub_not_enabled_for_post_type' ), 10, 1 );
+		}
+	}
+
+	/**
+	 * Check if ActivityPub is enabled for the custom post type of the event plugin.
+	 *
+	 * @return bool
+	 */
+	private function event_post_type_is_not_activitypub_enabled(): bool {
+		return ! in_array( $this->event_plugin::get_post_type(), get_option( 'activitypub_support_post_types', array() ), true );
+	}
+
+	/**
+	 * Display the admin notices for the plugins.
+	 *
+	 * @return void
+	 */
+	public function admin_notice_activitypub_not_enabled_for_post_type(): void {
+		if ( $this->event_plugin::is_plugin_page() ) {
+			$this->do_admin_notice_post_type_not_activitypub_enabled();
+		}
+	}
+
+	/**
+	 * Print admin notice that the current post type is not enabled in the ActivityPub plugin.
+	 *
+	 * @return void
+	 */
+	private function do_admin_notice_post_type_not_activitypub_enabled(): void {
+		$all_plugins       = get_plugins();
+		$event_plugin_file = $this->event_plugin::get_relative_plugin_file();
+		if ( isset( $all_plugins[ $event_plugin_file ]['Name'] ) ) {
+			$event_plugin_name = $all_plugins[ $event_plugin_file ]['Name'];
+		} elseif ( isset( get_mu_plugins()[ $event_plugin_file ]['Name'] ) ) {
+			$event_plugin_name = get_mu_plugins()[ $event_plugin_file ]['Name'];
+		} else {
+			return;
+		}
+		$activitypub_plugin_data = get_plugin_data( ACTIVITYPUB_PLUGIN_FILE );
+		$notice                  = sprintf(
+			/* translators: 1: the name of the event plugin a admin notice is shown. 2: The name of the ActivityPub plugin. */
+			_x(
+				'You have installed the <i>%1$s</i> plugin, but the event post type of the plugin <i>%2$s</i> is <b>not enabled</b> in the <a href="%3$s">%1$s settings</a>.',
+				'admin notice',
+				'event-bridge-for-activitypub'
+			),
+			esc_html( $activitypub_plugin_data['Name'] ),
+			esc_html( $event_plugin_name ),
+			admin_url( 'options-general.php?page=activitypub&tab=settings' )
+		);
+		$allowed_html = array(
+			'a' => array(
+				'href'  => true,
+				'title' => true,
+			),
+			'b' => array(),
+			'i' => array(),
+		);
+		echo '<div class="notice notice-warning is-dismissible"><p>' . \wp_kses( $notice, $allowed_html ) . '</p></div>';
+	}
+}

includes/admin/class-general-admin-notices.php

@@ -0,0 +1,149 @@
+<?php
+/**
+ * Class responsible for general admin notices.
+ *
+ * Notices for guiding to proper configuration of this plugin.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Admin;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Class responsible for general admin notices.
+ *
+ * Notices for guiding to proper configuration of this plugin.
+ *   - ActivityPub plugin not installed and activated
+ *   - No supported Event Plugin installed and activated
+ *
+ * @since 1.0.0
+ */
+class General_Admin_Notices {
+	/**
+	 * URL of the ActivityPub plugin. Needed when the ActivityPub plugin is not installed.
+	 */
+	const ACTIVITYPUB_PLUGIN_URL = 'https://wordpress.org/plugins/activitypub';
+
+	const EVENT_BRIDGE_FOR_ACTIVITYPUB_SUPPORTED_EVENT_PLUGINS_URL = 'https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub#supported-event-plugins';
+
+	/**
+	 * Allowed HTML for admin notices.
+	 *
+	 * @var array
+	 */
+	const ALLOWED_HTML = array(
+		'a' => array(
+			'href'   => true,
+			'title'  => true,
+			'target' => true,
+		),
+		'br',
+		'i',
+	);
+
+	/**
+	 * Admin notice when the ActivityPub plugin is not enabled.
+	 *
+	 * @return string
+	 */
+	public static function get_admin_notice_activitypub_plugin_not_enabled(): string {
+		return sprintf(
+			/* translators: 1: An URL that points to the ActivityPub plugin. */
+			_x(
+				'For the Event Bridge for ActivityPub to work, you will need to install and activate the <a href="%1$s">ActivityPub</a> plugin.',
+				'admin notice',
+				'event-bridge-for-activitypub'
+			),
+			esc_html( self::ACTIVITYPUB_PLUGIN_URL )
+		);
+	}
+
+	/**
+	 * Admin notice when the ActivityPub plugin version is too old.
+	 *
+	 * @return string
+	 */
+	public static function get_admin_notice_activitypub_plugin_version_too_old(): string {
+		return sprintf(
+			/* translators: 1: The name of the ActivityPub plugin. 2: The minimum required version number of the ActivityPub plugin. */
+			_x(
+				'Please upgrade your <a href="%1$s">ActivityPub</a> plugin. At least version %2$s is required for the Event Bridge for ActivityPub to work.',
+				'admin notice',
+				'event-bridge-for-activitypub'
+			),
+			esc_html( self::ACTIVITYPUB_PLUGIN_URL ),
+			esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_ACTIVITYPUB_PLUGIN_MIN_VERSION )
+		);
+	}
+
+	/**
+	 * Warning that no supported event plugin can be found.
+	 *
+	 * @return string
+	 */
+	public static function get_admin_notice_no_supported_event_plugin_active(): string {
+		return sprintf(
+			/* translators: 1: An URL to the list of supported event plugins. */
+			_x(
+				'The Plugin <i>Event Bridge for ActivityPub</i> is of no use, because you do not have installed and activated a supported Event Plugin.
+				<br> For a list of supported Event Plugins see  <a href="%1$s" target="_blank">here</a>.',
+				'admin notice',
+				'event-bridge-for-activitypub'
+			),
+			esc_url( self::EVENT_BRIDGE_FOR_ACTIVITYPUB_SUPPORTED_EVENT_PLUGINS_URL )
+		);
+	}
+
+	/**
+	 * Warning to fix status issues first.
+	 *
+	 * @return string
+	 */
+	public static function get_admin_notice_status_not_ok(): string {
+		return sprintf(
+			/* translators: 1: An URL to the list of supported event plugins. */
+			_x(
+				'The Plugin <i>Event Bridge for ActivityPub</i> is of no use, because you do not have installed and activated a supported Event Plugin.
+				<br> For a list of supported Event Plugins see  <a href="%1$s">here</a>.',
+				'admin notice',
+				'event-bridge-for-activitypub'
+			),
+			esc_html( self::EVENT_BRIDGE_FOR_ACTIVITYPUB_SUPPORTED_EVENT_PLUGINS_URL )
+		);
+	}
+
+	/**
+	 * Warning if the plugin is Active and the ActivityPub plugin is not.
+	 *
+	 * @return void
+	 */
+	public static function activitypub_plugin_not_enabled(): void {
+		$notice = self::get_admin_notice_activitypub_plugin_not_enabled();
+		echo '<div class="notice notice-warning"><p>' . \wp_kses( $notice, self::ALLOWED_HTML ) . '</p></div>';
+	}
+
+	/**
+	 * Warning if the plugin is Active and the ActivityPub plugins version is too old.
+	 *
+	 * @return void
+	 */
+	public static function activitypub_plugin_version_too_old(): void {
+		$notice = self::get_admin_notice_activitypub_plugin_version_too_old();
+		echo '<div class="notice notice-warning"><p>' . \wp_kses( $notice, self::ALLOWED_HTML ) . '</p></div>';
+	}
+
+	/**
+	 * Warning when no supported Even Plugin is installed and active.
+	 *
+	 * @return void
+	 */
+	public static function no_supported_event_plugin_active(): void {
+		$notice = self::get_admin_notice_no_supported_event_plugin_active();
+		echo '<div class="notice notice-warning"><p>' . \wp_kses( $notice, self::ALLOWED_HTML ) . '</p></div>';
+	}
+}

includes/admin/class-health-check.php

@@ -0,0 +1,190 @@
+<?php
+/**
+ * Health_Check class.
+ *
+ * @package Activitypub_Event_Bridge
+ */
+
+namespace Event_Bridge_For_ActivityPub\Admin;
+
+use Activitypub\Transformer\Factory as Transformer_Factory;
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+use Event_Bridge_For_ActivityPub\Setup;
+use WP_Query;
+
+/**
+ * ActivityPub Health_Check Class.
+ */
+class Health_Check {
+	/**
+	 * Initialize health checks.
+	 */
+	public static function init() {
+		\add_filter( 'site_status_tests', array( self::class, 'add_tests' ) );
+		\add_filter( 'debug_information', array( self::class, 'add_debug_information' ) );
+	}
+
+	/**
+	 * Add tests to the Site Health Check.
+	 *
+	 * @param array $tests The test array.
+	 *
+	 * @return array The filtered test array.
+	 */
+	public static function add_tests( $tests ) {
+		$tests['direct']['event_bridge_for_activitypub_test'] = array(
+			'label' => __( 'ActivityPub Event Transformer Test', 'event-bridge-for-activitypub' ),
+			'test'  => array( self::class, 'test_event_transformation' ),
+		);
+
+		return $tests;
+	}
+
+	/**
+	 * The the transformation of the most recent event posts.
+	 *
+	 * @return array
+	 */
+	public static function test_event_transformation() {
+		$result = array(
+			'label'       => \__( 'Transformation of Events to a valid ActivityStreams representation.', 'event-bridge-for-activitypub' ),
+			'status'      => 'good',
+			'badge'       => array(
+				'label' => \__( 'Event Bridge for ActivityPub', 'event-bridge-for-activitypub' ),
+				'color' => 'green',
+			),
+			'description' => \sprintf(
+				'<p>%s</p>',
+				\__( 'The transformation of your most recent events was successful.', 'event-bridge-for-activitypub' )
+			),
+			'actions'     => '',
+			'test'        => 'test_event_transformation',
+		);
+
+		$check = self::transform_most_recent_event_posts();
+
+		if ( true === $check ) {
+			return $result;
+		}
+
+		$result['status']         = 'critical';
+		$result['label']          = \__( 'One or more of your most recent events failed to transform to ActivityPub', 'event-bridge-for-activitypub' );
+		$result['badge']['color'] = 'red';
+		$result['description']    = \sprintf(
+			'<p>%s</p>',
+			$check->get_error_message()
+		);
+
+		return $result;
+	}
+
+	/**
+	 * Test if right transformer gets applied.
+	 *
+	 * @param Event_Plugin $event_plugin  The event plugin definition.
+	 *
+	 * @return bool True if the check passed.
+	 */
+	public static function test_if_event_transformer_is_used( $event_plugin ) {
+		// Get a (random) event post.
+		$event_posts = self::get_most_recent_event_posts( $event_plugin->get_post_type(), 1 );
+
+		// If no post is found, we can not do this test.
+		if ( ! $event_posts || is_wp_error( $event_posts ) || empty( $event_posts ) ) {
+			return true;
+		}
+
+		// Call the transformer Factory.
+		$transformer = Transformer_Factory::get_transformer( $event_posts[0] );
+		// Check that we got the right transformer.
+		$desired_transformer_class = $event_plugin::get_activitypub_event_transformer_class();
+		if ( $transformer instanceof $desired_transformer_class ) {
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * Retrieves the most recently published event posts of a certain event post type.
+	 *
+	 * @param ?string $event_post_type  The post type of the events.
+	 * @param ?int    $number_of_posts  The maximum number of events to return.
+	 *
+	 * @return WP_Post[]|false         Array of event posts, or false if none are found.
+	 */
+	public static function get_most_recent_event_posts( $event_post_type = null, $number_of_posts = 5 ) {
+		if ( ! $event_post_type ) {
+			$active_event_plugins = Setup::get_instance()->get_active_event_plugins();
+			$active_event_plugin  = reset( $active_event_plugins );
+			if ( ! $active_event_plugin ) {
+				return false;
+			}
+			$event_post_type = $active_event_plugin->get_post_type();
+		}
+
+		$args = array(
+			'numberposts'      => $number_of_posts,
+			'category'         => 0,
+			'orderby'          => 'date',
+			'order'            => 'DESC',
+			'include'          => array(),
+			'exclude'          => array(),
+			'meta_key'         => '',
+			'meta_value'       => '',
+			'post_type'        => $event_post_type,
+			'suppress_filters' => true,
+		);
+
+		$query = new WP_Query();
+		return $query->query( $args );
+	}
+
+	/**
+	 * Transform the most recent event posts.
+	 */
+	public static function transform_most_recent_event_posts() {
+		return true;
+	}
+
+	/**
+	 * Retrieves information like name and version from active event plugins.
+	 */
+	private static function get_info_about_active_event_plugins() {
+		$active_event_plugins = Setup::get_instance()->get_active_event_plugins();
+		$info                 = array();
+		foreach ( $active_event_plugins as $active_event_plugin ) {
+			$event_plugin_file    = $active_event_plugin->get_relative_plugin_file();
+			$event_plugin_data    = \get_plugin_data( $event_plugin_file );
+			$event_plugin_name    = isset( $event_plugin_data['Plugin Name'] ) ? $event_plugin_data['Plugin Name'] : 'Name not found';
+			$event_plugin_version = isset( $event_plugin_version['Plugin Version'] ) ? $event_plugin_version['Plugin Version'] : 'Version not found';
+
+			$info[] = array(
+				'event_plugin_name'    => $event_plugin_name,
+				'event_plugin_version' => $event_plugin_version,
+				'event_plugin_file'    => $event_plugin_file,
+			);
+		}
+	}
+
+	/**
+	 * Static function for generating site debug data when required.
+	 *
+	 * @param  array $info  The debug information to be added to the core information page.
+	 * @return array        The extended information.
+	 */
+	public static function add_debug_information( $info ) {
+		$info['event_bridge_for_activitypub'] = array(
+			'label'  => __( 'Event Bridge for ActivityPub', 'event-bridge-for-activitypub' ),
+			'fields' => array(
+				'plugin_version'       => array(
+					'label'   => __( 'Plugin Version', 'event-bridge-for-activitypub' ),
+					'value'   => EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION,
+					'private' => true,
+				),
+				'active_event_plugins' => self::get_info_about_active_event_plugins(),
+			),
+		);
+
+		return $info;
+	}
+}

includes/admin/class-settings-page.php

@@ -0,0 +1,132 @@
+<?php
+/**
+ * General settings class.
+ *
+ * This file contains the General class definition, which handles the "General" settings
+ * page for the Event Bridge for ActivityPub Plugin, providing options for configuring various general settings.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Admin;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+use Event_Bridge_For_ActivityPub\Setup;
+
+/**
+ * Class responsible for the Event Bridge for ActivityPub related Settings.
+ *
+ * Class which handles the "General" settings page for the Event Bridge for ActivityPub Plugin,
+ * providing options for configuring various general settings.
+ *
+ * @since 1.0.0
+ */
+class Settings_Page {
+	const STATIC = 'Event_Bridge_For_ActivityPub\Admin\Settings_Page';
+
+	const SETTINGS_SLUG = 'event-bridge-for-activitypub';
+	/**
+	 * Warning if the plugin is Active and the ActivityPub plugin is not.
+	 *
+	 * @return void
+	 */
+	public static function admin_menu(): void {
+		\add_options_page(
+			'Event Bridge for ActivityPub',
+			__( 'Event Bridge for ActivityPub', 'event-bridge-for-activitypub' ),
+			'manage_options',
+			self::SETTINGS_SLUG,
+			array( self::STATIC, 'settings_page' ),
+		);
+	}
+
+	/**
+	 * Adds Link to the settings page in the plugin page.
+	 * It's called via apply_filter('plugin_action_links_' . PLUGIN_NAME).
+	 *
+	 * @param array $links    Already added links.
+	 *
+	 * @return array          Original links but with link to setting page added.
+	 */
+	public static function settings_link( $links ): array {
+		return array_merge(
+			$links,
+			array(
+				'<a href="' . admin_url( 'options-general.php?page=' . self::SETTINGS_SLUG ) . '">Settings</a>',
+			)
+		);
+	}
+
+	/**
+	 * Receive the event categories (terms) used by the event plugin.
+	 *
+	 * @param Event_Plugin $event_plugin Contains info about a certain event plugin.
+	 *
+	 * @return array An array of Terms.
+	 */
+	private static function get_event_terms( $event_plugin ): array {
+		$taxonomy = $event_plugin::get_event_category_taxonomy();
+		if ( $taxonomy ) {
+			$event_terms = get_terms(
+				array(
+					'taxonomy'   => $taxonomy,
+					'hide_empty' => true,
+				)
+			);
+			return ! is_wp_error( $event_terms ) ? $event_terms : array();
+		} else {
+			return array();
+		}
+	}
+
+	/**
+	 * Preparing the data and loading the template for the settings page.
+	 *
+	 * @return void
+	 */
+	public static function settings_page(): void {
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
+		if ( empty( $_GET['tab'] ) ) {
+			$tab = 'welcome';
+		} else {
+			// phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			$tab = sanitize_key( $_GET['tab'] );
+		}
+
+		// Fallback to always re-scan active event plugins, when user visits admin area of this plugin.
+		Setup::get_instance()->redetect_active_event_plugins();
+
+		switch ( $tab ) {
+			case 'settings':
+				$plugin_setup = Setup::get_instance();
+
+				$event_plugins = $plugin_setup->get_active_event_plugins();
+
+				$event_terms = array();
+
+				foreach ( $event_plugins as $event_plugin ) {
+					$event_terms = array_merge( $event_terms, self::get_event_terms( $event_plugin ) );
+				}
+
+				$args = array(
+					'slug'        => self::SETTINGS_SLUG,
+					'event_terms' => $event_terms,
+				);
+
+				\load_template( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . 'templates/settings.php', true, $args );
+				break;
+			case 'welcome':
+			default:
+				wp_enqueue_script( 'plugin-install' );
+				add_thickbox();
+				wp_enqueue_script( 'updates' );
+
+				\load_template( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . 'templates/welcome.php', true );
+				break;
+		}
+	}
+}

includes/category-mapper.php

@@ -1,67 +0,0 @@
-<?php
-
-/**
- * Mapping of WordPress Terms(Tags) to known Event Categories
- *
- * @package activity-event-transformers
- * @license AGPL-3.0-or-later
- */
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
-
-use Activitypub\Activity\Extended_Object\Event;
-
-/**
- * ActivityPub Tribe Transformer
- *
- * @since 1.0.0
- */
-class Category_Mapper {
-
-	/**
-	 * Static function to do the Mapping
-	 **/
-	public static function map( $post_categories ) {
-
-		if ( empty( $post_categories ) ) {
-			return 'MEETING';
-		}
-
-		// Prepare an array to store all category information for comparison.
-		$category_info = array();
-
-		// Extract relevant category information (name, slug, description) from the categories array.
-		foreach ( $post_categories as $category ) {
-			$category_info[] = strtolower( $category->name );
-			$category_info[] = strtolower( $category->slug );
-			$category_info[] = strtolower( $category->description );
-		}
-
-		// Convert mobilizon categories to lowercase for case-insensitive comparison.
-		$mobilizon_categories = array_map( 'strtolower', Event::DEFAULT_EVENT_CATEGORIES );
-
-		// Initialize variables to track the best match.
-		$best_mobilizon_category_match = '';
-		$best_match_length             = 0;
-
-		// Check for the best match.
-		foreach ( $mobilizon_categories as $mobilizon_category ) {
-			foreach ( $category_info as $category ) {
-				foreach ( explode( '_', $mobilizon_category ) as $mobilizon_category_slice ) {
-					if ( stripos( $category, $mobilizon_category_slice ) !== false ) {
-						// Check if the current match is longer than the previous best match.
-						$current_match_legnth = strlen( $mobilizon_category_slice );
-						if ( $current_match_legnth > $best_match_length ) {
-							$best_mobilizon_category_match = $mobilizon_category;
-							$best_match_length             = $current_match_legnth;
-						}
-					}
-				}
-			}
-		}
-
-		return ( '' != $best_mobilizon_category_match ) ? strtoupper( $best_mobilizon_category_match ) : 'MEETING';
-	}
-}

includes/class-autoloader.php

@@ -0,0 +1,67 @@
+<?php
+/**
+ * Class responsible for autoloading Event Bridge for ActivityPub class files.
+ *
+ * The Autoloader class is responsible for automatically loading class files as needed
+ * to ensure a clean and organized codebase. It maps class names to their corresponding
+ * file locations within the GatherPress plugin.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Class Autoloader.
+ *
+ * This class is responsible for automatic loading of classes and namespaces.
+ *
+ * @since 1.0.0
+ */
+class Autoloader {
+	/**
+	 * Register method for autoloader.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	public static function register(): void {
+		spl_autoload_register(
+			function ( $full_class ) {
+				$base_dir = EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . '/includes/';
+				$base     = 'Event_Bridge_For_ActivityPub\\';
+
+				if ( strncmp( $full_class, $base, strlen( $base ) ) === 0 ) {
+					$maybe_uppercase = str_replace( $base, '', $full_class );
+					$class           = strtolower( $maybe_uppercase );
+					// All classes should be capitalized. If this is instead looking for a lowercase method, we ignore that.
+					if ( $maybe_uppercase === $class ) {
+						return;
+					}
+
+					if ( false !== strpos( $class, '\\' ) ) {
+						$parts    = explode( '\\', $class );
+						$class    = array_pop( $parts );
+						$sub_dir  = strtr( implode( '/', $parts ), '_', '-' );
+						$base_dir = $base_dir . $sub_dir . '/';
+					}
+
+					$filename = 'class-' . strtr( $class, '_', '-' );
+					$file     = $base_dir . $filename . '.php';
+
+					if ( file_exists( $file ) && is_readable( $file ) ) {
+						require_once $file;
+					} else {
+						\wp_die( sprintf( esc_html( 'Required class not found or not readable: %s' ), esc_html( $full_class ) ) );
+					}
+				}
+			}
+		);
+	}
+}

includes/class-settings.php

@@ -0,0 +1,139 @@
+<?php
+/**
+ * General settings class.
+ *
+ * This file contains the General class definition, which handles the "General" settings
+ * page for the Event Bridge for ActivityPub Plugin, providing options for configuring various general settings.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Activitypub\Activity\Extended_Object\Event;
+
+/**
+ * Class responsible for the ActivityPui Event Extension related Settings.
+ *
+ * Class responsible for the ActivityPui Event Extension related Settings.
+ *
+ * @since 1.0.0
+ */
+class Settings {
+	const SETTINGS_SLUG = 'event-bridge-for-activitypub';
+
+	/**
+	 * The default ActivityPub event category.
+	 *
+	 * @var string
+	 */
+	const DEFAULT_EVENT_CATEGORY = 'MEETING';
+
+	/**
+	 * Register the settings for the Event Bridge for ActivityPub plugin.
+	 *
+	 * @return void
+	 */
+	public static function register_settings(): void {
+		\register_setting(
+			'event-bridge-for-activitypub',
+			'event_bridge_for_activitypub_default_event_category',
+			array(
+				'type'              => 'string',
+				'description'       => \__( 'Define your own custom post template', 'event-bridge-for-activitypub' ),
+				'show_in_rest'      => true,
+				'default'           => self::DEFAULT_EVENT_CATEGORY,
+				'sanitize_callback' => array( self::class, 'sanitize_mapped_event_category' ),
+			)
+		);
+
+		\register_setting(
+			'event-bridge-for-activitypub',
+			'event_bridge_for_activitypub_event_category_mappings',
+			array(
+				'type'              => 'array',
+				'description'       => \__( 'Define your own custom post template', 'event-bridge-for-activitypub' ),
+				'default'           => array(),
+				'sanitize_callback' => array( self::class, 'sanitize_event_category_mappings' ),
+			)
+		);
+
+		\register_setting(
+			'event-bridge-for-activitypub',
+			'event_bridge_for_activitypub_initially_activated',
+			array(
+				'type'        => 'boolean',
+				'description' => \__( 'Whether the plugin just got activated for the first time.', 'event-bridge-for-activitypub' ),
+				'default'     => 1,
+			)
+		);
+
+		\register_setting(
+			'event-bridge-for-activitypub',
+			'event_bridge_for_activitypub_summary_type',
+			array(
+				'type'         => 'string',
+				'description'  => \__( 'Summary type to use for ActivityStreams', 'event-bridge-for-activitypub' ),
+				'show_in_rest' => true,
+				'default'      => 'preset',
+			)
+		);
+
+		\register_setting(
+			'event-bridge-for-activitypub',
+			'event_bridge_for_activitypub_custom_summary',
+			array(
+				'type'         => 'string',
+				'description'  => \__( 'Define your own custom summary template for events', 'event-bridge-for-activitypub' ),
+				'show_in_rest' => true,
+				'default'      => EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY,
+			)
+		);
+	}
+
+	/**
+	 * Sanitize the target ActivityPub Event category.
+	 *
+	 * @param string $event_category The ActivityPUb event category.
+	 */
+	public static function sanitize_mapped_event_category( $event_category ): string {
+		return self::is_allowed_event_category( $event_category ) ? $event_category : self::DEFAULT_EVENT_CATEGORY;
+	}
+
+	/**
+	 * Sanitization function for the event category mapping setting.
+	 *
+	 * Currently only the default event categories are allowed to be target of a mapping.
+	 *
+	 * @param array $event_category_mappings The settings value.
+	 *
+	 * @return array An array that contains only valid mapping pairs.
+	 */
+	public static function sanitize_event_category_mappings( $event_category_mappings ): array {
+		if ( empty( $event_category_mappings ) ) {
+			return array();
+		}
+		foreach ( $event_category_mappings as $taxonomy_slug => $event_category ) {
+			if ( ! self::is_allowed_event_category( $event_category ) ) {
+				unset( $event_category_mappings[ $taxonomy_slug ] );
+			}
+		}
+		return $event_category_mappings;
+	}
+
+	/**
+	 * Checks if the given event category is allowed to be target of a mapping.
+	 *
+	 * @param string $event_category The event category to check.
+	 *
+	 * @return bool True if allowed, false otherwise.
+	 */
+	private static function is_allowed_event_category( $event_category ): bool {
+		$allowed_event_categories = Event::DEFAULT_EVENT_CATEGORIES;
+		return in_array( $event_category, $allowed_event_categories, true );
+	}
+}

includes/class-setup.php

@@ -0,0 +1,356 @@
+<?php
+/**
+ * Class responsible for initializing Event Bridge for ActivityPub.
+ *
+ * The setup class provides function for checking if this plugin should be activated.
+ * It detects supported event plugins and provides all setup hooks and filters.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Event_Bridge_For_ActivityPub\Admin\Event_Plugin_Admin_Notices;
+use Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices;
+use Event_Bridge_For_ActivityPub\Admin\Health_Check;
+use Event_Bridge_For_ActivityPub\Admin\Settings_Page;
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+
+require_once ABSPATH . 'wp-admin/includes/plugin.php';
+
+/**
+ * Class Setup.
+ *
+ * This class is responsible for initializing Event Bridge for ActivityPub.
+ *
+ * @since 1.0.0
+ */
+class Setup {
+	/**
+	 * Keep the information whether the ActivityPub plugin is active.
+	 *
+	 * @var boolean
+	 */
+	protected $activitypub_plugin_is_active = false;
+
+	/**
+	 * Keep the current version of the current ActivityPub plugin.
+	 *
+	 * @var string
+	 */
+	protected $activitypub_plugin_version = '';
+
+	/**
+	 * Holds an array of the currently activated supported event plugins.
+	 *
+	 * @var Event_Plugin[]
+	 */
+	protected $active_event_plugins = array();
+
+	/**
+	 * Constructor for the Setup class.
+	 *
+	 * Initializes and sets up various components of the plugin.
+	 *
+	 * @since 1.0.0
+	 */
+	protected function __construct() {
+		$this->activitypub_plugin_is_active = defined( 'ACTIVITYPUB_PLUGIN_VERSION' ) ||
+			is_plugin_active( 'activitypub/activitypub.php' );
+		// BeforeFirstRelease: decide whether we want to do anything at all when ActivityPub plugin is note active.
+		// if ( ! $this->activitypub_plugin_is_active ) {
+		// deactivate_plugins( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE );
+		// return;
+		// }.
+		$this->activitypub_plugin_version = self::get_activitypub_plugin_version();
+		add_action( 'plugins_loaded', array( $this, 'setup_hooks' ) );
+	}
+
+	/**
+	 * The single instance of the class.
+	 *
+	 * @since 1.0.0
+	 * @var ?self|null The instance of the class.
+	 */
+	private static $instance = null;
+
+	/**
+	 * Get the instance of the Singleton class.
+	 *
+	 * If an instance does not exist, it creates one; otherwise, it returns the existing instance.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return self The instance of the class.
+	 */
+	public static function get_instance(): self {
+		if ( null === self::$instance ) {
+			self::$instance = new self();
+		}
+
+		return self::$instance;
+	}
+
+	/**
+	 * LooksUp the current version of the ActivityPub.
+	 *
+	 * @return string The semantic Version.
+	 */
+	private static function get_activitypub_plugin_version(): string {
+		if ( defined( 'ACTIVITYPUB_PLUGIN_VERSION' ) ) {
+			return constant( 'ACTIVITYPUB_PLUGIN_VERSION' );
+		}
+		return '0.0.0';
+	}
+
+	/**
+	 * Getter function for the active event plugins.
+	 *
+	 * @return Event_Plugin[]
+	 */
+	public function get_active_event_plugins() {
+		return $this->active_event_plugins;
+	}
+
+	/**
+	 * Holds all the classes for the supported event plugins.
+	 *
+	 * @var array
+	 */
+	private const EVENT_PLUGIN_CLASSES = array(
+		'\Event_Bridge_For_ActivityPub\Integrations\Events_Manager',
+		'\Event_Bridge_For_ActivityPub\Integrations\GatherPress',
+		'\Event_Bridge_For_ActivityPub\Integrations\The_Events_Calendar',
+		'\Event_Bridge_For_ActivityPub\Integrations\VS_Event_List',
+		'\Event_Bridge_For_ActivityPub\Integrations\WP_Event_Manager',
+		'\Event_Bridge_For_ActivityPub\Integrations\Eventin',
+		'\Event_Bridge_For_ActivityPub\Integrations\Modern_Events_Calendar_Lite',
+		'\Event_Bridge_For_ActivityPub\Integrations\Event_Organiser',
+	);
+
+	/**
+	 * Force the re-scan for active event plugins without using the cached transient.
+	 *
+	 * @return void
+	 */
+	public function redetect_active_event_plugins(): void {
+		delete_transient( 'event_bridge_for_activitypub_active_event_plugins' );
+		$this->detect_active_event_plugins();
+	}
+
+	/**
+	 * Function that checks for supported activated event plugins.
+	 *
+	 * @return array List of supported event plugins as keys from the SUPPORTED_EVENT_PLUGINS const.
+	 */
+	public function detect_active_event_plugins(): array {
+		$active_event_plugins = get_transient( 'event_bridge_for_activitypub_active_event_plugins' );
+
+		if ( $active_event_plugins ) {
+			$this->active_event_plugins = $active_event_plugins;
+			return $active_event_plugins;
+		}
+
+		if ( ! function_exists( 'get_plugins' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/plugin.php';
+		}
+
+		$all_plugins = array_merge( get_plugins(), get_mu_plugins() );
+
+		$active_event_plugins = array();
+		foreach ( self::EVENT_PLUGIN_CLASSES as $event_plugin_class ) {
+			$event_plugin_file = call_user_func( array( $event_plugin_class, 'get_relative_plugin_file' ) );
+			if ( ! $event_plugin_file ) {
+				continue;
+			}
+			if ( array_key_exists( $event_plugin_file, $all_plugins ) && \is_plugin_active( $event_plugin_file ) ) {
+				$active_event_plugins[ $event_plugin_file ] = new $event_plugin_class();
+			}
+		}
+		set_transient( 'event_bridge_for_activitypub_active_event_plugins', $active_event_plugins );
+		$this->active_event_plugins = $active_event_plugins;
+		return $active_event_plugins;
+	}
+
+	/**
+	 * Set up hooks for various purposes.
+	 *
+	 * This method adds hooks for different purposes as needed.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	public function setup_hooks(): void {
+		$this->detect_active_event_plugins();
+
+		register_activation_hook( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE, array( $this, 'activate' ) );
+
+		add_action( 'activated_plugin', array( $this, 'redetect_active_event_plugins' ) );
+		add_action( 'deactivated_plugin', array( $this, 'redetect_active_event_plugins' ) );
+
+		add_action( 'admin_init', array( $this, 'do_admin_notices' ) );
+		add_action( 'admin_init', array( Settings::class, 'register_settings' ) );
+		add_action( 'admin_enqueue_scripts', array( self::class, 'enqueue_styles' ) );
+		add_action( 'admin_menu', array( Settings_Page::class, 'admin_menu' ) );
+		add_filter(
+			'plugin_action_links_' . EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_BASENAME,
+			array( Settings_Page::class, 'settings_link' )
+		);
+
+		// If we don't have any active event plugins, or the ActivityPub plugin is not enabled, abort here.
+		if ( empty( $this->active_event_plugins ) || ! $this->activitypub_plugin_is_active ) {
+			return;
+		}
+
+		add_action( 'init', array( Health_Check::class, 'init' ) );
+
+		// Check if the minimum required version of the ActivityPub plugin is installed.
+		if ( ! version_compare( $this->activitypub_plugin_version, EVENT_BRIDGE_FOR_ACTIVITYPUB_ACTIVITYPUB_PLUGIN_MIN_VERSION ) ) {
+			return;
+		}
+
+		add_filter( 'activitypub_transformer', array( $this, 'register_activitypub_event_transformer' ), 10, 3 );
+	}
+
+	/**
+	 * Add the CSS for the admin pages.
+	 *
+	 * @param string $hook_suffix The suffix of the hook.
+	 *
+	 * @return void
+	 */
+	public static function enqueue_styles( $hook_suffix ): void {
+		if ( false !== strpos( $hook_suffix, 'event-bridge-for-activitypub' ) ) {
+			wp_enqueue_style(
+				'event-bridge-for-activitypub-admin-styles',
+				plugins_url(
+					'assets/css/event-bridge-for-activitypub-admin.css',
+					EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE
+				),
+				array(),
+				EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION
+			);
+			wp_enqueue_script(
+				'event-bridge-for-activitypub-admin-script',
+				plugins_url(
+					'assets/js/event-bridge-for-activitypub-admin.js',
+					EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE
+				),
+				array( 'jquery' ),
+				EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION,
+				false
+			);
+		}
+	}
+
+	/**
+	 * Fires the initialization of admin notices.
+	 */
+	public function do_admin_notices(): void {
+		foreach ( $this->active_event_plugins as $event_plugin ) {
+			new Event_Plugin_Admin_Notices( $event_plugin );
+		}
+		// Check if any general admin notices are needed and add actions to insert the needed admin notices.
+		if ( ! $this->activitypub_plugin_is_active ) {
+			// The ActivityPub plugin is not active.
+			add_action( 'admin_notices', array( 'Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices', 'activitypub_plugin_not_enabled' ), 10, 1 );
+		}
+		if ( ! version_compare( $this->activitypub_plugin_version, EVENT_BRIDGE_FOR_ACTIVITYPUB_ACTIVITYPUB_PLUGIN_MIN_VERSION ) ) {
+			// The ActivityPub plugin is too old.
+			add_action( 'admin_notices', array( 'Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices', 'activitypub_plugin_version_too_old' ), 10, 1 );
+		}
+		if ( empty( $this->active_event_plugins ) ) {
+			// No supported Event Plugin is active.
+			add_action( 'admin_notices', array( 'Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices', 'no_supported_event_plugin_active' ), 10, 1 );
+		}
+	}
+
+	/**
+	 * Add the custom transformers for the events of several WordPress event plugins.
+	 *
+	 * @param Activitypub\Transformer\Base $transformer  The transformer to use.
+	 * @param mixed                        $wp_object    The WordPress object to transform.
+	 * @param string                       $object_class The class of the object to transform.
+	 *
+	 * @return \Activitypub\Transformer\Base|null
+	 */
+	public function register_activitypub_event_transformer( $transformer, $wp_object, $object_class ): ?\Activitypub\Transformer\Base {
+		// If the current WordPress object is not a post (e.g., a WP_Comment), don't change the transformer.
+		if ( 'WP_Post' !== $object_class ) {
+			return $transformer;
+		}
+
+		// Get the transformer for a specific event plugins event-post type.
+		foreach ( $this->active_event_plugins as $event_plugin ) {
+			if ( $wp_object->post_type === $event_plugin->get_post_type() ) {
+				$transformer_class = $event_plugin::get_activitypub_event_transformer_class();
+				if ( class_exists( $transformer_class ) ) {
+					return new $transformer_class( $wp_object, $event_plugin::get_event_category_taxonomy() );
+				}
+			}
+		}
+
+		// Return the default transformer.
+		return $transformer;
+	}
+
+	/**
+	 * Activates ActivityPub support for all active event plugins event post-types.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	public function activate_activitypub_support_for_active_event_plugins(): void {
+		// If someone installs this plugin, we simply enable ActivityPub support for all currently active event post types.
+		$activitypub_supported_post_types = get_option( 'activitypub_support_post_types', array() );
+		foreach ( $this->active_event_plugins as $event_plugin ) {
+			if ( ! in_array( $event_plugin->get_post_type(), $activitypub_supported_post_types, true ) ) {
+				$activitypub_supported_post_types[] = $event_plugin->get_post_type();
+				add_post_type_support( $event_plugin->get_post_type(), 'activitypub' );
+			}
+		}
+		update_option( 'activitypub_support_post_types', $activitypub_supported_post_types );
+	}
+
+	/**
+	 * Activates the Event Bridge for ActivityPub plugin.
+	 *
+	 * This method handles the activation of the Event Bridge for ActivityPub plugin.
+	 *
+	 * @since 1.0.0
+	 * @see register_activation_hook()
+	 * @return void
+	 */
+	public function activate(): void {
+		$this->redetect_active_event_plugins();
+		// Don't allow plugin activation, when the ActivityPub plugin is not activated yet.
+		if ( ! $this->activitypub_plugin_is_active ) {
+			deactivate_plugins( plugin_basename( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) );
+			$notice = General_Admin_Notices::get_admin_notice_activitypub_plugin_not_enabled();
+			wp_die(
+				wp_kses( $notice, General_Admin_Notices::ALLOWED_HTML ),
+				'Plugin dependency check',
+				array( 'back_link' => true ),
+			);
+		}
+
+		if ( empty( $this->active_event_plugins ) ) {
+			deactivate_plugins( plugin_basename( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) );
+			$notice = General_Admin_Notices::get_admin_notice_no_supported_event_plugin_active();
+			wp_die(
+				wp_kses( $notice, General_Admin_Notices::ALLOWED_HTML ),
+				'Plugin dependency check',
+				array( 'back_link' => true ),
+			);
+		}
+
+		self::activate_activitypub_support_for_active_event_plugins();
+	}
+}

includes/event-categories.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * File responsible for defining the event category strings.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub;
+
+define(
+	'EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES',
+	array(
+		'ARTS'                          => __( 'Arts', 'event-bridge-for-activitypub' ),
+		'BOOK_CLUBS'                    => __( 'Book clubs', 'event-bridge-for-activitypub' ),
+		'BUSINESS'                      => __( 'Business', 'event-bridge-for-activitypub' ),
+		'CAUSES'                        => __( 'Causes', 'event-bridge-for-activitypub' ),
+		'COMEDY'                        => __( 'Comedy', 'event-bridge-for-activitypub' ),
+		'CRAFTS'                        => __( 'Crafts', 'event-bridge-for-activitypub' ),
+		'FOOD_DRINK'                    => __( 'Food & Drink', 'event-bridge-for-activitypub' ),
+		'HEALTH'                        => __( 'Health', 'event-bridge-for-activitypub' ),
+		'MUSIC'                         => __( 'Music', 'event-bridge-for-activitypub' ),
+		'AUTO_BOAT_AIR'                 => __( 'Auto, boat and air', 'event-bridge-for-activitypub' ),
+		'COMMUNITY'                     => __( 'Community', 'event-bridge-for-activitypub' ),
+		'FAMILY_EDUCATION'              => __( 'Family & Education', 'event-bridge-for-activitypub' ),
+		'FASHION_BEAUTY'                => __( 'Fashion & Beauty', 'event-bridge-for-activitypub' ),
+		'FILM_MEDIA'                    => __( 'Film & Media', 'event-bridge-for-activitypub' ),
+		'GAMES'                         => __( 'Games', 'event-bridge-for-activitypub' ),
+		'LANGUAGE_CULTURE'              => __( 'Language & Culture', 'event-bridge-for-activitypub' ),
+		'LEARNING'                      => __( 'Learning', 'event-bridge-for-activitypub' ),
+		'LGBTQ'                         => __( 'LGBTQ', 'event-bridge-for-activitypub' ),
+		'MOVEMENTS_POLITICS'            => __( 'Movements and politics', 'event-bridge-for-activitypub' ),
+		'NETWORKING'                    => __( 'Networking', 'event-bridge-for-activitypub' ),
+		'PARTY'                         => __( 'Party', 'event-bridge-for-activitypub' ),
+		'PERFORMING_VISUAL_ARTS'        => __( 'Performing & Visual Arts', 'event-bridge-for-activitypub' ),
+		'PETS'                          => __( 'Pets', 'event-bridge-for-activitypub' ),
+		'PHOTOGRAPHY'                   => __( 'Photography', 'event-bridge-for-activitypub' ),
+		'OUTDOORS_ADVENTURE'            => __( 'Outdoors & Adventure', 'event-bridge-for-activitypub' ),
+		'SPIRITUALITY_RELIGION_BELIEFS' => __( 'Spirituality, Religion & Beliefs', 'event-bridge-for-activitypub' ),
+		'SCIENCE_TECH'                  => __( 'Science & Tech', 'event-bridge-for-activitypub' ),
+		'SPORTS'                        => __( 'Sports', 'event-bridge-for-activitypub' ),
+		'THEATRE'                       => __( 'Theatre', 'event-bridge-for-activitypub' ),
+		'MEETING'                       => __( 'Meeting', 'event-bridge-for-activitypub' ), // Default value in federation.
+		'DEFAULT'                       => __( 'Default', 'event-bridge-for-activitypub' ), // Internal default for overrides.
+	),
+);

includes/integrations/class-event-organiser.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * Event Organiser.
+ *
+ * Defines all the necessary meta information for the Event Organiser plugin.
+ *
+ * @link    https://wordpress.org/plugins/event-organiser/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class Event_Organiser extends Event_Plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'event-organiser/event-organiser.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return 'event';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		return array( 'event-organiser' );
+	}
+
+	/**
+	 * Returns the ActivityPub transformer class.
+	 *
+	 * @return string
+	 */
+	public static function get_activitypub_transformer_class_name(): string {
+		return 'Event_Organiser';
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return 'event-category';
+	}
+}

includes/integrations/class-event-plugin.php

@@ -0,0 +1,88 @@
+<?php
+/**
+ * Interface for defining supported Event Plugins.
+ *
+ * Basic information that each supported event needs for this plugin to work.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+abstract class Event_Plugin {
+	/**
+	 * Returns the plugin file relative to the plugins dir.
+	 *
+	 * @return string
+	 */
+	abstract public static function get_relative_plugin_file(): string;
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	abstract public static function get_post_type(): string;
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	abstract public static function get_event_category_taxonomy(): string;
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The IDs of one or several admin/settings pages.
+	 */
+	public static function get_settings_pages(): array {
+		return array();
+	}
+
+	/**
+	 * Get the plugins name from the main plugin-file's top-level-file-comment.
+	 */
+	final public static function get_plugin_name(): string {
+		$all_plugins = array_merge( get_plugins(), get_mu_plugins() );
+		if ( isset( $all_plugins[ static::get_relative_plugin_file() ]['Name'] ) ) {
+			return $all_plugins[ static::get_relative_plugin_file() ]['Name'];
+		} else {
+			return '';
+		}
+	}
+
+	/**
+	 * Detects whether the current screen is a admin page of the event plugin.
+	 */
+	public static function is_plugin_page(): bool {
+		// Get the current page.
+		$screen = get_current_screen();
+
+		// Check if we are on a edit page for the event, or on the settings page of the event plugin.
+		$is_event_plugins_edit_page     = 'edit' === $screen->base && static::get_post_type() === $screen->post_type;
+		$is_event_plugins_settings_page = in_array( $screen->id, static::get_settings_pages(), true );
+
+		return $is_event_plugins_edit_page || $is_event_plugins_settings_page;
+	}
+
+	/**
+	 * Returns the Activitypub transformer for the event plugins event post type.
+	 */
+	public static function get_activitypub_event_transformer_class(): string {
+		return str_replace( 'Integrations', 'Activitypub\Transformer', static::class );
+	}
+}

includes/integrations/class-eventin.php

@@ -0,0 +1,60 @@
+<?php
+/**
+ * The Events Calendar.
+ *
+ * Defines all the necessary meta information for the events calendar.
+ *
+ * @link    https://wordpress.org/plugins/the-events-calendar/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class Eventin extends Event_plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'wp-event-solution/eventin.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return 'etn';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page url.
+	 */
+	public static function get_settings_pages(): array {
+		return array( 'eventin' ); // Base always is wp-admin/admin.php?page=eventin.
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return 'etn_category';
+	}
+}

includes/integrations/class-events-manager.php

@@ -0,0 +1,60 @@
+<?php
+/**
+ * Events Manager.
+ *
+ * Defines all the necessary meta information for the Events Manager WordPress Plugin.
+ *
+ * @link    https://wordpress.org/plugins/events-manager/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class Events_Manager extends Event_Plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'events-manager/events-manager.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return defined( 'EM_POST_TYPE_EVENT' ) ? constant( 'EM_POST_TYPE_EVENT' ) : 'event';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_page(): array {
+		return array();
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return defined( 'EM_TAXONOMY_CATEGORY' ) ? constant( 'EM_TAXONOMY_CATEGORY' ) : 'event-categories';
+	}
+}

includes/integrations/class-gatherpress.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * GatherPress.
+ *
+ * Defines all the necessary meta information for the GatherPress plugin.
+ *
+ * @link    https://wordpress.org/plugins/gatherpress/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class GatherPress extends Event_Plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'gatherpress/gatherpress.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return class_exists( '\GatherPress\Core\Event' ) ? \GatherPress\Core\Event::POST_TYPE : 'gatherpress_event';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		return array( class_exists( '\GatherPress\Core\Utility' ) ? \GatherPress\Core\Utility::prefix_key( 'general' ) : 'gatherpress_general' );
+	}
+
+	/**
+	 * Returns the ActivityPub transformer class.
+	 *
+	 * @return string
+	 */
+	public static function get_activitypub_transformer_class_name(): string {
+		return 'GatherPress';
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return class_exists( '\GatherPress\Core\Topic' ) ? \GatherPress\Core\Topic::TAXONOMY : 'gatherpress_topic';
+	}
+}

includes/integrations/class-modern-events-calendar-lite.php

@@ -0,0 +1,61 @@
+<?php
+/**
+ * Modern Events Calendar (Lite)
+ *
+ * Defines all the necessary meta information for the Modern Events Calendar (Lite).
+ *
+ * @link    https://webnus.net/modern-events-calendar/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class Modern_Events_Calendar_Lite extends Event_plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'modern-events-calendar-lite/modern-events-calendar-lite.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		// See MEC_feature_events->get_main_post_type().
+		return 'mec-events';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		return array( 'MEC-settings', 'MEC-support', 'MEC-ix', 'MEC-wizard', 'MEC-addons', 'mec-intro' );
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return 'mec_category';
+	}
+}

includes/integrations/class-the-events-calendar.php

@@ -0,0 +1,65 @@
+<?php
+/**
+ * The Events Calendar.
+ *
+ * Defines all the necessary meta information for the events calendar.
+ *
+ * @link    https://wordpress.org/plugins/the-events-calendar/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class The_Events_Calendar extends Event_plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'the-events-calendar/the-events-calendar.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return class_exists( '\Tribe__Events__Main' ) ? \Tribe__Events__Main::POSTTYPE : 'tribe_event';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		if ( class_exists( '\Tribe\Events\Admin\Settings' ) ) {
+			$page = \Tribe\Events\Admin\Settings::$settings_page_id;
+		} else {
+			$page = 'tec-events-settings';
+		}
+		return array( $page );
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return class_exists( '\Tribe__Events__Main' ) ? \Tribe__Events__Main::TAXONOMY : 'tribe_events_cat';
+	}
+}

includes/integrations/class-vs-event-list.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * VS Events LIst.
+ *
+ * Defines all the necessary meta information for the WordPress event plugin
+ * "Very Simple Events List".
+ *
+ * @link    https://de.wordpress.org/plugins/very-simple-event-list/
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+use Event_Bridge_For_ActivityPub\Event_Plugins;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class VS_Event_List extends Event_Plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'very-simple-event-list/vsel.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return 'event';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		return array( 'settings_page_vsel' );
+	}
+
+	/**
+	 * Returns the ActivityPub transformer class.
+	 *
+	 * @return string
+	 */
+	public static function get_activitypub_transformer_class_name(): string {
+		return 'VS_Event';
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return 'event_cat';
+	}
+}

includes/integrations/class-wp-event-manager.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * WP Event Manager.
+ *
+ * Defines all the necessary meta information for the WordPress event plugin
+ * "WP Event Manager"
+ *
+ * @link    https://de.wordpress.org/plugins/wp-event-manager
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for a supported event plugin.
+ *
+ * This interface defines which information is necessary for a supported event plugin.
+ *
+ * @since 1.0.0
+ */
+final class WP_Event_Manager extends Event_Plugin {
+	/**
+	 * Returns the full plugin file.
+	 *
+	 * @return string
+	 */
+	public static function get_relative_plugin_file(): string {
+		return 'wp-event-manager/wp-event-manager.php';
+	}
+
+	/**
+	 * Returns the event post type of the plugin.
+	 *
+	 * @return string
+	 */
+	public static function get_post_type(): string {
+		return 'event_listing';
+	}
+
+	/**
+	 * Returns the IDs of the admin pages of the plugin.
+	 *
+	 * @return array The settings page urls.
+	 */
+	public static function get_settings_pages(): array {
+		return array( 'event-manager-settings' );
+	}
+
+	/**
+	 * Returns the ActivityPub transformer class.
+	 *
+	 * @return string
+	 */
+	public static function get_activitypub_transformer_class_name(): string {
+		return 'WP_Event_Manager';
+	}
+
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return 'event_listing_category';
+	}
+}

package.json

@@ -0,0 +1,29 @@
+
+{
+  "name": "event-bridge-for-activitypub",
+  "version": "0.1.0",
+  "author": {
+    "name": "André Menrath",
+    "web": "https://graz.social/@linos"
+  },
+  "scripts": {
+    "dev": "wp-scripts start",
+    "build": "wp-scripts build",
+    "readme": "grunt wp_readme_to_markdown",
+    "env-start": "wp-env start && wp-env run cli wp rewrite structure '/%year%/%monthnum%/%postname%/'",
+    "env-stop": "wp-env stop"
+  },
+  "license": "AGPL-3.0",
+  "bugs": {
+    "url": "https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub/issues"
+  },
+  "devDependencies": {
+      "@wordpress/env": "^10.10.0",
+      "@wordpress/scripts": "^30.0.2",
+      "classnames": "^2.3.2",
+      "grunt": "^1.1.0",
+      "grunt-checktextdomain": "^1.0.1",
+      "grunt-wp-i18n": "^1.0.3",
+      "grunt-wp-readme-to-markdown": "^2.0.1"
+  }
+}

phpcs.xml

@@ -0,0 +1,159 @@
+<?xml version="1.0"?>
+<ruleset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Example Project" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/PHPCSStandards/PHP_CodeSniffer/master/phpcs.xsd">
+
+	<description>A custom set of rules to check for a WPized WordPress project</description>
+
+	<!--
+	#############################################################################
+	COMMAND LINE ARGUMENTS
+	https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Annotated-Ruleset
+	#############################################################################
+	-->
+
+	<file>.</file>
+
+	<!-- Exclude WP Core folders and files from being checked. -->
+	<exclude-pattern>/docroot/wp-admin/*</exclude-pattern>
+	<exclude-pattern>/docroot/wp-includes/*</exclude-pattern>
+	<exclude-pattern>/docroot/wp-*.php</exclude-pattern>
+	<exclude-pattern>/docroot/index.php</exclude-pattern>
+	<exclude-pattern>/docroot/xmlrpc.php</exclude-pattern>
+	<exclude-pattern>/docroot/wp-content/plugins/*</exclude-pattern>
+
+	<!-- Exclude the Composer Vendor directory. -->
+	<exclude-pattern>/vendor/*</exclude-pattern>
+
+	<!-- Exclude the Node Modules directory. -->
+	<exclude-pattern>/node_modules/*</exclude-pattern>
+
+	<!-- Exclude minified Javascript files. -->
+	<exclude-pattern>*.min.js</exclude-pattern>
+
+	<!-- Exclude the Grundfile.js. -->
+	<exclude-pattern>Gruntfile.js</exclude-pattern>
+
+	<!-- Strip the filepaths down to the relevant bit. -->
+	<arg name="basepath" value="."/>
+
+	<!-- Check up to 8 files simultaneously. -->
+	<arg name="parallel" value="8"/>
+
+
+	<!--
+	#############################################################################
+	SET UP THE RULESETS
+	#############################################################################
+	-->
+
+	<!-- Include the WordPress-Extra standard. -->
+	<rule ref="WordPress-Extra">
+		<!--
+		We may want a middle ground though. The best way to do this is add the
+		entire ruleset, then rule by rule, remove ones that don't suit a project.
+		We can do this by running `phpcs` with the '-s' flag, which allows us to
+		see the names of the sniffs reporting errors.
+		Once we know the sniff names, we can opt to exclude sniffs which don't
+		suit our project like so.
+
+		The below two examples just show how you can exclude rules/error codes.
+		They are not intended as advice about which sniffs to exclude.
+		-->
+
+		<!--
+		<exclude name="WordPress.WhiteSpace.ControlStructureSpacing"/>
+		<exclude name="Modernize.FunctionCalls.Dirname.Nested"/>
+		-->
+	</rule>
+
+	<!-- Let's also check that everything is properly documented. -->
+	<rule ref="WordPress-Docs"/>
+
+	<!-- Add in some extra rules from other standards. -->
+	<rule ref="Generic.Commenting.Todo"/>
+
+	<!-- Check for PHP cross-version compatibility. -->
+	<!--
+	To enable this, the PHPCompatibilityWP standard needs
+	to be installed.
+	See the readme for installation instructions:
+	https://github.com/PHPCompatibility/PHPCompatibilityWP
+	For more information, also see:
+	https://github.com/PHPCompatibility/PHPCompatibility
+	-->
+	<!--
+	<config name="testVersion" value="5.6-"/>
+	<rule ref="PHPCompatibilityWP">
+		<include-pattern>*\.php</include-pattern>
+	</rule>
+	-->
+
+
+	<!--
+	#############################################################################
+	SNIFF SPECIFIC CONFIGURATION
+	#############################################################################
+	-->
+
+	<!--
+	To get the optimal benefits of using WordPressCS, we should add a couple of
+	custom properties.
+	Adjust the values of these properties to fit our needs.
+
+	For information on additional custom properties available, check out
+	the wiki:
+	https://github.com/WordPress/WordPress-Coding-Standards/wiki/Customizable-sniff-properties
+	-->
+	<config name="minimum_wp_version" value="6.6"/>
+
+	<rule ref="WordPress.WP.I18n">
+		<properties>
+			<property name="text_domain" type="array">
+				<element value="event-bridge-for-activitypub"/>
+			</property>
+		</properties>
+	</rule>
+
+	<rule ref="WordPress.NamingConventions.PrefixAllGlobals">
+		<properties>
+			<property name="prefixes" type="array">
+				<element value="EVENT_BRIDGE_FOR_ACTIVITYPUB"/>
+			</property>
+		</properties>
+	</rule>
+
+
+	<!--
+	#############################################################################
+	SELECTIVE EXCLUSIONS
+	Exclude specific files for specific sniffs and/or exclude sub-groups in sniffs.
+	#############################################################################
+	-->
+
+	<!--
+	Sometimes, you may want to exclude a certain directory, like your tests,
+	for select sniffs.
+	The below examples demonstrate how to do this.
+
+	In the example, the `GlobalVariablesOverride` rule is excluded for test files
+	as it is sometimes necessary to overwrite WP globals in test situations (just
+	don't forget to restore them after the test!).
+
+	Along the same lines, PHPUnit is getting stricter about using PSR-4 file names,
+	so excluding test files from the `WordPress.Files.Filename` sniff can be a
+	legitimate exclusion.
+
+	For more information on ruleset configuration options, check out the PHPCS wiki:
+	https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Annotated-Ruleset
+	-->
+	<rule ref="WordPress.NamingConventions.PrefixAllGlobals">
+		<exclude-pattern>tests/*.php</exclude-pattern>
+		<exclude-pattern>templates/*.php</exclude-pattern>
+	</rule>
+	<rule ref="WordPress.WP.GlobalVariablesOverride">
+		<exclude-pattern>tests/*.php</exclude-pattern>
+	</rule>
+	<rule ref="WordPress.Files.FileName">
+		<exclude-pattern>tests/*.php</exclude-pattern>
+	</rule>
+
+</ruleset>

phpunit.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<phpunit
+	bootstrap="tests/bootstrap.php"
+	backupGlobals="false"
+	colors="true"
+	convertErrorsToExceptions="true"
+	convertNoticesToExceptions="true"
+	convertWarningsToExceptions="true"
+	>
+	<testsuites>
+		<testsuite name="testing">
+			<directory prefix="test-" suffix=".php">./tests/</directory>
+		</testsuite>
+	</testsuites>
+</phpunit>

readme.txt

@@ -1,15 +1,100 @@
-=== ActivityPub Event Extensions ===
-Contributors: menrath
-Tags: events, fediverse, activitypub, activitystream
-Requires at least: 5.5
-Tested up to: 6.4
-Stable tag: 1.0.0
+=== Event Bridge for ActivityPub ===
+Contributors: andremenrath
+Tags: events, fediverse, activitypub, calendar
+Requires at least: 6.5
+Tested up to: 6.7
+Stable tag: 0.3.3
 Requires PHP: 7.4
 License: AGPL-3.0-or-later
-License URI: https://www.gngnuu.org/licenses/agpl-3.0.html
-
-The ActivityPub Event Extensions
+License URI: https://www.gnu.org/licenses/agpl-3.0.html
+Integrating popular event plugins with the ActivityPub plugin.
 
 == Description ==
 
+Make your events more discoverable, expand your reach effortlessly while being independent of other (commercial) platforms, and be a part of the growing decentralized web (the Fediverse).
+With the Event Bridge for ActivityPub Plugin for WordPress, your events can be automatically followed, aggregated and displayed across decentralized platforms like [Mastodon](https://joinmastodon.org) or [Gancio](https://gancio.org), without any extra work.
+Forget the hassle of managing multiple social media accounts just to keep your audience informed.
 
+This plugin is not an event managing plugin but an add-on to popular event plugins. It extends their functionality to fully support the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/).
+With the ActivityPub plugin people can follow your website directly and engage with your events just as they would on social media: liking, boosting and even commenting if you enable it.
+You retain full ownership of your content. By integrating into your existing setup, it ensures no extra work is needed while enhancing your events' visibility across the web.
+
+= How It Works =
+
+With the Event Bridge for ActivityPub WordPress plugin, sharing your events is effortless and automatic!
+Once you create an event on your WordPress site, it is seamlessly shared across the decentralized web using the ActivityPub protocol.
+
+![](./.wordpress-org/event-activitypub-publishing.gif)
+
+Your events can be automatically delivered to platforms that fully support events, such as [Mobilizon](https://joinmobilizon.org/), [Gancio](https://gancio.org), [Friendica](https://friendi.ca), [Hubzilla](https://hubzilla.org), and [Pleroma](https://pleroma.social/).
+These platforms create public event calendars by pulling in events from various sources, including your website. Any updates you make to your events are synced across these platforms—so you only need to manage your events on your own site, with no extra work required.
+
+![](./.wordpress-org/decentralized-event-calenders.gif)
+
+Even platforms that don't yet fully support events, like [Mastodon](https://joinmastodon.org), will still receive a detailed, well-composed summary of your event.
+The Event Federation plugin ensures that users from those platforms are provided with all important information about an event.
+
+= Features for Your WordPress Events and the Fediverse =
+
+**ActivityPub-Enabled Event Sharing:** Your WordPress events are now compatible with the Fediverse, using the ActivityStreams format. This means your events can be easily discovered and followed by users on platforms like Mastodon and other ActivityPub-compatible services.
+
+**Automatic Event Summaries:** When your event is shared on the Fediverse, platforms like Mastodon that don't fully support events will display a brief HTML summary of key details — such as the event's title, start time, and location. This ensures that even if someone can't view the full event on their platform, they still get the important info at a glance, with a link to your WordPress event page. Advanced users can create custom summaries via a set of shortcodes.
+
+**Improved Event Discoverability:** Your custom event categories are mapped to a set of default categories used in the Fediverse, helping your events reach a wider audience. This improves the chances that users searching for similar events on other platforms will find yours.
+
+**Event Reminders for Your Followers:** Often, events are planned well in advance. To keep your followers informed right in time, you can set up reminders that are supposed to trigger the events showing up in their timelines right before the event starts. At the moment this reminder is implemented as a self-boost of your original event post. While this feature may behave differently across various platforms, we are working on a more robust solution that will let you schedule dedicated reminder notes that appear in all followers' timelines.
+
+== Installation ==
+
+This plugin depends on the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/). Additionally, you need to use one of the supported event Plugins.
+
+= Supported Event Plugins =
+
+* [The Events Calendar](https://de.wordpress.org/plugins/the-events-calendar/)
+* [VS Event List](https://de.wordpress.org/plugins/very-simple-event-list/)
+* [Events Manager](https://de.wordpress.org/plugins/events-manager/)
+* [WP Event Manager](https://de.wordpress.org/plugins/wp-event-manager/)
+* [Eventin](https://de.wordpress.org/plugins/wp-event-solution/)
+* [Modern Events Calendar Lite](https://webnus.net/modern-events-calendar/)
+* [GatherPress](https://gatherpress.org/)
+* [Event Organiser](https://wordpress.org/plugins/event-organiser/)
+
+== Configuration ==
+
+If you're new to the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/), it’s recommended to spend a few minutes reading through its documentation to familiarize yourself with its setup and functionality.
+
+== Frequently Asked Questions ==
+
+= Do I need to install another event plugin to use the Event Federation Plugin? =
+
+Yes, this plugin works as an add-on and requires both the ActivityPub plugin and a supported event plugin such as The Events Calendar, VS Event List, or Events Manager to manage your events. It just fills the missing gap between event plugins and the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/).
+
+= What platforms can follow my events? =
+
+Your events can be followed on platforms that support ActivityPub like [Mobilizon](https://joinmobilizon.org/), [Gancio](https://gancio.org), [Friendica](https://friendi.ca), [Hubzilla](https://hubzilla.org), and [Pleroma](https://pleroma.social/). Even other applications like [Mastodon](https://joinmastodon.org), which don't fully support events yet, will display all important information about the events.
+
+= How much extra work is required to maintain my events across the decentralized Web? =
+
+None! Once the plugin is set up, your events are automatically sent to all connected platforms or account that follow you (your Website). Any updates you make to your events are synced without additional effort.
+
+= Can I still use social media to promote my events? =
+
+Yes, you can still use traditional social media if you wish. However, this plugin helps reduce reliance on commercial platforms by connecting your events to the decentralized Fediverse.
+
+= Will this plugin work if I don't use the ActivityPub plugin? =
+
+No, the Event Federation Plugin depends on the [ActivityPub plugin](https://wordpress.org/plugins/activitypub/) to deliver your events across decentralized platforms, so it's essential to have it installed and configured.
+
+= My event plugin is not supported, what can I do? =
+
+If you know about coding have a look at the documentation of how to add your plugin or open an [issue](https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub/issues), if we can spare some free hours we might add it.
+
+= What if I experience problems? =
+
+We're always interested in your feedback. Feel free to reach out to us via [E-Mail](https://event-federation.eu/contact/) or create an [issue](https://code.event-federation.eu/Event-Federation/wordpress-event-bridge-for-activitypub/issues).
+
+== Changelog ==
+
+= [0.3.3] 2024-12-19 =
+
+* Initial release on https://wordpress.org/

templates/admin-header.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Template for the header and navigation of the admin pages.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/* @var array $args Template arguments. */
+$args = wp_parse_args(
+	$args,
+	array(
+		'welcome'  => '',
+		'settings' => '',
+	)
+);
+?>
+
+<div class="event-bridge-for-activitypub-settings-header">
+	<div class="event-bridge-for-activitypub-settings-title-section">
+		<h1><?php \esc_html_e( 'Event Bridge for ActivityPub', 'event-bridge-for-activitypub' ); ?></h1>
+	</div>
+
+	<nav class="event-bridge-for-activitypub-settings-tabs-wrapper" aria-label="<?php \esc_attr_e( 'Secondary menu', 'event-bridge-for-activitypub' ); ?>">
+		<a href="<?php echo \esc_url( admin_url( 'options-general.php?page=event-bridge-for-activitypub' ) ); ?>" class="event-bridge-for-activitypub-settings-tab <?php echo \esc_attr( $args['welcome'] ); ?>">
+			<?php \esc_html_e( 'Welcome', 'event-bridge-for-activitypub' ); ?>
+		</a>
+
+		<a href="<?php echo \esc_url( admin_url( 'options-general.php?page=event-bridge-for-activitypub&tab=settings' ) ); ?>" class="event-bridge-for-activitypub-settings-tab <?php echo \esc_attr( $args['settings'] ); ?>">
+			<?php \esc_html_e( 'Settings', 'event-bridge-for-activitypub' ); ?>
+		</a>
+	</nav>
+</div>
+<hr class="wp-header-end">

templates/settings.php

@@ -0,0 +1,152 @@
+<?php
+/**
+ * Template for Event Bridge for ActivityPub settings page.
+ *
+ * This template is used to display and manage settings for the Event Bridge for ActivityPub plugin.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ *
+ * @param array  $args An array of arguments for the settings page.
+ */
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+\load_template(
+	__DIR__ . '/admin-header.php',
+	true,
+	array(
+		'settings' => 'active',
+	)
+);
+
+use Activitypub\Activity\Extended_Object\Event;
+
+if ( ! isset( $args ) || ! array_key_exists( 'event_terms', $args ) ) {
+	return;
+}
+
+if ( ! current_user_can( 'manage_options' ) ) {
+	return;
+}
+
+$event_terms = $args['event_terms'];
+
+require_once EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . '/includes/event-categories.php';
+
+$selected_default_event_category = \get_option( 'event_bridge_for_activitypub_default_event_category', 'MEETING' );
+$current_category_mapping        = \get_option( 'event_bridge_for_activitypub_event_category_mappings', array() );
+?>
+
+<div class="event-bridge-for-activitypub-settings event-bridge-for-activitypub-settings-page hide-if-no-js">
+	<form method="post" action="options.php">
+		<?php \settings_fields( 'event-bridge-for-activitypub' ); ?>
+		<div class="box">
+			<h2> <?php esc_html_e( 'Event Summary Text', 'event-bridge-for-activitypub' ); ?> </h2>
+			<p><?php esc_html_e( 'Many Fediverse applications (e.g., Mastodon) don\'t fully support events, instead they will show a summary text along with the events title and the URL to your Website.', 'event-bridge-for-activitypub' ); ?></p>
+			<p>
+				<label for="event_bridge_for_activitypub_summary_type_preset">
+					<input type="radio" name="event_bridge_for_activitypub_summary_type" id="event_bridge_for_activitypub_summary_type_preset" value="preset" <?php echo \checked( 'preset', \get_option( 'event_bridge_for_activitypub_summary_type', EVENT_BRIDGE_FOR_ACTIVITYPUB_DEFAULT_SUMMARY_TYPE ) ); ?> />
+					<?php \esc_html_e( 'Automatic (default)', 'event-bridge-for-activitypub' ); ?>
+					-
+					<span class="description">
+						<?php \esc_html_e( 'Let the plugin compose a summary for you.	', 'event-bridge-for-activitypub' ); ?>
+					</span>
+				</label>
+			</p>
+			<p>
+				<label for="event_bridge_for_activitypub_summary_type_custom">
+					<input type="radio" name="event_bridge_for_activitypub_summary_type" id="event_bridge_for_activitypub_summary_type_custom" value="custom" <?php echo \checked( 'custom', \get_option( 'event_bridge_for_activitypub_summary_type', EVENT_BRIDGE_FOR_ACTIVITYPUB_DEFAULT_SUMMARY_TYPE ) ); ?> />
+					<?php \esc_html_e( 'Custom', 'event-bridge-for-activitypub' ); ?>
+					-
+					<span class="description">
+						<?php \esc_html_e( 'For advanced users: compose your custom summary via shortcodes.', 'event-bridge-for-activitypub' ); ?>
+					</span>
+				</label>
+			</p>
+			<div id="event_bridge_for_activitypub_summary_type_custom-details">
+				<textarea name="event_bridge_for_activitypub_custom_summary" id="event_bridge_for_activitypub_custom_summary" rows="10" cols="50" class="large-text" placeholder="<?php echo wp_kses( EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY, 'post' ); ?>"><?php echo esc_textarea( wp_kses( \get_option( 'event_bridge_for_activitypub_custom_summary', EVENT_BRIDGE_FOR_ACTIVITYPUB_CUSTOM_SUMMARY ), 'post' ) ); ?></textarea>
+				<details>
+					<summary><?php esc_html_e( 'See a list Template Tags available for the summary.', 'event-bridge-for-activitypub' ); ?></summary>
+					<div class="description">
+						<dl>
+							<dt><code>[ap_start_time]</code><dt>
+							<dd><?php \esc_html_e( 'The events title.', 'event-bridge-for-activitypub' ); ?></dd>
+							<dt><code>[ap_end_time]</code><dt>
+							<dd><?php \esc_html_e( 'The events content.', 'event-bridge-for-activitypub' ); ?></dd>
+							<dt><code>[ap_location]</code><dt>
+							<dd><?php \esc_html_e( 'The events location.', 'event-bridge-for-activitypub' ); ?></dd>
+							<dt><code>[ap_hashtags]</code><dt>
+							<dd><?php \esc_html_e( 'The events tags as hashtags.', 'event-bridge-for-activitypub' ); ?></dd>
+							<dt><code>[ap_excerpt]</code><dt>
+							<dd><?php \esc_html_e( 'The events excerpt (may be truncated).', 'event-bridge-for-activitypub' ); ?></dd>
+							<dt><code>[ap_content]</code><dt>
+							<dd><?php \esc_html_e( 'The events description.', 'event-bridge-for-activitypub' ); ?></dd>
+						</dl>
+					</div>
+				</details>
+			</div>
+		</div>
+
+		<div class="box">
+			<h2> <?php esc_html_e( 'ActivityPub Event Category', 'event-bridge-for-activitypub' ); ?> </h2>
+			<p> <?php esc_html_e( 'To help visitors find events more easily, the community created a set of basic event categories. Please select the category that best matches the majority of the events you organize.', 'event-bridge-for-activitypub' ); ?> </p>
+			<table class="form-table">
+				<tr>
+					<th scope="row"> <?php esc_html_e( 'Default Category', 'event-bridge-for-activitypub' ); ?> </th>
+					<td>
+						<select id="event_bridge_for_activitypub_default_event_category" name="event_bridge_for_activitypub_default_event_category">';
+						<?php
+						foreach ( EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES as $value => $label ) {
+							echo '<option value="' . esc_attr( $value ) . '" ' . selected( $selected_default_event_category, $value, false ) . '>' . esc_html( $label ) . '</option>';
+						}
+						?>
+						</select>
+					</td>
+				</tr>
+			</table>
+
+			<?php if ( ! empty( $event_terms ) ) : ?>
+			<h3> <?php esc_html_e( 'Advanced Event Category Settings', 'event-bridge-for-activitypub' ); ?> </h3>
+			<p> <?php esc_html_e( 'Take more control by adjusting how your event categories are mapped to the basic category set used in ActivityPub. This option lets you override the default selection above, ensuring more accurate categorization and better visibility for your events.', 'event-bridge-for-activitypub' ); ?> </p>
+			<table class="form-table">
+				<?php foreach ( $event_terms as $event_term ) { ?>
+					<tr>
+						<th scope="row"> <?php echo esc_html( $event_term->name ); ?> </th>
+						<td>
+							<select name="event_bridge_for_activitypub_event_category_mappings[<?php echo esc_attr( $event_term->slug ); ?>]">
+								<?php
+								$current_mapping_is_set = false;
+								if ( ! empty( $current_category_mapping ) ) {
+									$current_mapping_is_set = array_key_exists( $event_term->slug, $current_category_mapping );
+								}
+								if ( $current_mapping_is_set ) {
+									$mapping = $current_category_mapping[ $event_term->slug ];
+								} else {
+									$mapping = 'DEFAULT';
+								}
+								if ( 'DEFAULT' === $mapping ) {
+									echo '<option value="' . esc_attr( $mapping ) . '"> -- ' . esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES[ $mapping ] ) . ' -- </option>';
+								} else {
+									echo '<option value="' . esc_attr( $mapping ) . '">' . esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES[ $mapping ] ) . '</option>';
+								}
+								echo '<option value="DEFAULT" ' . selected( $selected_default_event_category, 'DEFAULT', false ) . '> -- ' . esc_html__( 'Default', 'event-bridge-for-activitypub' ) . ' -- </option>';
+								foreach ( Event::DEFAULT_EVENT_CATEGORIES as $event_category ) {
+									echo '<option value="' . esc_attr( $event_category ) . '" ' . selected( $mappings[ $event_term->slug ] ?? '', $event_category, false ) . '>' . esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_EVENT_CATEGORIES[ $event_category ] ) . '</option>';
+								}
+								?>
+							</select>
+						</td>
+					</tr>
+				<?php } ?>
+			</table>
+			<?php endif; ?>
+		</div>
+		<!-- This disables the setup wizard. -->
+		<div class="hidden">
+			<input type="checkbox" id="event_bridge_for_activitypub_initially_activated" name="event_bridge_for_activitypub_initially_activated"/>
+		</div>
+		<?php \submit_button(); ?>
+	</form>
+</div>

templates/welcome.php

@@ -0,0 +1,244 @@
+<?php
+/**
+ * Status page for the Event Bridge for ActivityPub.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use Event_Bridge_For_ActivityPub\Setup;
+use Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices;
+use Event_Bridge_For_ActivityPub\Admin\Settings_Page;
+use Event_Bridge_For_ActivityPub\Admin\Health_Check;
+
+\load_template(
+	__DIR__ . '/admin-header.php',
+	true,
+	array(
+		'welcome' => 'active',
+	)
+);
+
+$active_event_plugins                   = Setup::get_instance()->get_active_event_plugins();
+$event_bridge_for_activitypub_status_ok = true;
+$example_event_post                     = Health_Check::get_most_recent_event_posts();
+
+if ( empty( $example_event_post ) ) {
+	$example_event_post          = 'https://yoursite.com/events/event-name';
+	$example_event_post_is_dummy = true;
+} else {
+	$example_event_post          = \get_permalink( $example_event_post[0] );
+	$example_event_post_is_dummy = false;
+}
+
+global $wp_filesystem;
+WP_Filesystem();
+
+?>
+
+<div class="event-bridge-for-activitypub-settings event-bridge-for-activitypub-settings-page hide-if-no-js">
+	<div class="box">
+		<h2><?php \esc_html_e( 'Status', 'event-bridge-for-activitypub' ); ?></h2>
+		<p><?php \esc_html_e( 'The Event Bridge for ActivityPub detected the following (activated) event plugins:', 'event-bridge-for-activitypub' ); ?></p>
+			<?php
+			if ( empty( $active_event_plugins ) ) {
+				$notice = General_Admin_Notices::get_admin_notice_no_supported_event_plugin_active();
+			}
+			echo '<p>⚠' . \wp_kses( $notice, General_Admin_Notices::ALLOWED_HTML ) . '</p>';
+			?>
+			<?php foreach ( $active_event_plugins as $active_event_plugin ) { ?>
+			<h3><?php echo esc_html( $active_event_plugin->get_plugin_name() ); ?>:</h3>
+			<ul class="event-bridge-for-activitypub-list">
+				<li>
+					<?php
+					if ( in_array( $active_event_plugin::get_post_type(), get_option( 'activitypub_support_post_types', array() ), true ) ) {
+						echo '&#9989 ';
+						$status_message_post_type_enabled = sprintf(
+							/* translators: 1: the name of the event plugin a admin notice is shown. 2: The name of the ActivityPub plugin. */
+							_x(
+								'The ActivityPub support for the event post type of the plugin <i>%2$s</i> is enabled in the <a href="%3$s">%1$s settings</a>.',
+								'admin notice',
+								'event-bridge-for-activitypub'
+							),
+							esc_html( get_plugin_data( ACTIVITYPUB_PLUGIN_FILE )['Name'] ),
+							esc_html( $active_event_plugin->get_plugin_name() ),
+							admin_url( 'options-general.php?page=activitypub&tab=settings' )
+						);
+					} else {
+						$event_bridge_for_activitypub_status_ok = false;
+						echo '&#10060 ';
+						$status_message_post_type_enabled = sprintf(
+							/* translators: 1: the name of the event plugin a admin notice is shown. 2: The name of the ActivityPub plugin. */
+							_x(
+								'The post type for events of the plugin <i>%2$s</i> is <b>not enabled</b> in the <a href="%3$s">%1$s settings</a>.',
+								'admin notice',
+								'event-bridge-for-activitypub'
+							),
+							esc_html( get_plugin_data( ACTIVITYPUB_PLUGIN_FILE )['Name'] ),
+							esc_html( $active_event_plugin->get_plugin_name() ),
+							admin_url( 'options-general.php?page=activitypub&tab=settings' )
+						);
+					}
+					$allowed_html = array(
+						'a' => array(
+							'href'  => true,
+							'title' => true,
+						),
+						'b' => array(),
+						'i' => array(),
+					);
+					echo \wp_kses( $status_message_post_type_enabled, $allowed_html );
+					?>
+				</li>
+				<li>
+					<?php
+					if ( Health_Check::test_if_event_transformer_is_used( $active_event_plugin ) ) {
+						echo '&#9989 ';
+						esc_html_e( 'The Event Bridge for ActivityPub successfully registered to the ActivityPub plugin.', 'event-bridge-for-activitypub' );
+					} else {
+						$event_bridge_for_activitypub_status_ok = false;
+						echo '&#10060 ';
+						esc_html_e( 'The Event Bridge for ActivityPub could not register to the ActivityPub plugin.', 'event-bridge-for-activitypub' );
+					}
+					?>
+				</li>
+			</ul>
+		<?php } ?>
+	</div>
+
+	<?php if ( get_option( 'event_bridge_for_activitypub_initially_activated', true ) ) : ?>
+		<a href="<?php echo esc_url( admin_url( 'options-general.php?page=' . Settings_Page::SETTINGS_SLUG ) . '&tab=settings' ); ?>" role="button">
+			<button class="button button-primary">
+				<strong>→</strong> <?php \esc_html_e( 'Continue your setup', 'event-bridge-for-activitypub' ); ?>
+			</button>
+		</a>
+
+	<?php else : ?>
+
+	<div class="box">
+		<h2><?php \esc_html_e( 'How to Check if It\'s Working', 'event-bridge-for-activitypub' ); ?></h2>
+		<?php
+		if ( ! $event_bridge_for_activitypub_status_ok ) {
+			echo '<div class="notice-warning"><p>' . \esc_html__( 'Please fix the status issues above first.', 'event-bridge-for-activitypub' ) . '</p></div>';
+		}
+		?>
+		<p><?php esc_html_e( 'Most of the magic happens behind the scenes, but here is how you can verify that your events are ready to be discovered:', 'event-bridge-for-activitypub' ); ?></p>
+		<div class="event-bridge-for-activitypub-settings-accordion">
+			<h4 class="event-bridge-for-activitypub-settings-accordion-heading">
+				<button aria-expanded="false" class="event-bridge-for-activitypub-settings-accordion-trigger" aria-controls="event-bridge-for-activitypub-help-accordion-mastodon" type="button">
+					<span class="title">
+						1. 
+						<img src="<?php echo esc_url( plugins_url( '/assets/img/mastodon.svg', EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) ); ?>" alt="Mastodon Icon" class="event-bridge-for-activitypub-settings-inline-icon">
+						<?php \esc_html_e( 'Using Your Mastodon Account', 'event-bridge-for-activitypub' ); ?>
+					</span>
+					<span class="icon"></span>
+				</button>
+			</h4>
+			<div id="event-bridge-for-activitypub-help-accordion-mastodon" class="event-bridge-for-activitypub-settings-accordion-panel" hidden="hidden">
+				<ol class="event-bridge-for-activitypub-settings-numbered-list">
+					<li><?php \esc_html_e( 'Log into your Mastodon account.', 'event-bridge-for-activitypub' ); ?></li>
+					<li>
+						<?php \esc_html_e( 'In the search bar, type or copy the full URL of one of your event pages. For example:', 'event-bridge-for-activitypub' ); ?>
+						<code class="event-bridge-for-activitypub-settings-example-url"><?php echo \esc_url( $example_event_post ); ?></code>
+					</li>
+					<li><?php \esc_html_e( 'If everything is set up correctly, you\'ll see a post representing your event. It should include the event\'s image, title, and a brief description.', 'event-bridge-for-activitypub' ); ?></li>
+				</ol>
+			</div>
+			<h4 class="event-bridge-for-activitypub-settings-accordion-heading">
+				<button aria-expanded="false" class="event-bridge-for-activitypub-settings-accordion-trigger" aria-controls="event-bridge-for-activitypub-help-accordion-mobilizon" type="button">
+					<span class="title">
+						2. 
+						<img src="<?php echo esc_url( plugins_url( '/assets/img/mobilizon.svg', EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) ); ?>" alt="Mastodon Icon" class="event-bridge-for-activitypub-settings-inline-icon">
+						<?php \esc_html_e( 'Using Your Mobilizon Account', 'event-bridge-for-activitypub' ); ?>
+					</span>
+					<span class="icon"></span>
+				</button>
+			</h4>
+			<div id="event-bridge-for-activitypub-help-accordion-mobilizon" class="event-bridge-for-activitypub-settings-accordion-panel" hidden="hidden">
+				<ol class="event-bridge-for-activitypub-settings-numbered-list">
+					<li><?php \esc_html_e( 'Log into your Mobilizon account.', 'event-bridge-for-activitypub' ); ?></li>
+					<li>
+						<?php \esc_html_e( 'In the search bar, type or copy the full URL of one of your event pages. For example:', 'event-bridge-for-activitypub' ); ?>
+						<code class="event-bridge-for-activitypub-settings-example-url"><?php echo \esc_url( $example_event_post ); ?></code>
+					</li>
+					<li><?php \esc_html_e( 'If everything is set up correctly, you\'ll see a full representation of your WordPress event. This will include the event\'s banner image, title, complete description, start and end times, categories, tags, and whether it\'s an online event.', 'event-bridge-for-activitypub' ); ?></li>
+				</ol>
+			</div>
+			<h4 class="event-bridge-for-activitypub-settings-accordion-heading">
+				<button aria-expanded="false" class="event-bridge-for-activitypub-settings-accordion-trigger" aria-controls="event-bridge-for-activitypub-help-accordion-fediverse" type="button">
+					<span class="title">
+						3. 
+						<img src="<?php echo esc_url( plugins_url( '/assets/img/fediverse.svg', EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) ); ?>" alt="Mastodon Icon" class="event-bridge-for-activitypub-settings-inline-icon">
+						<?php \esc_html_e( 'Using Any Other Fediverse Application', 'event-bridge-for-activitypub' ); ?>
+					</span>
+					<span class="icon"></span>
+				</button>
+			</h4>
+			<div id="event-bridge-for-activitypub-help-accordion-fediverse" class="event-bridge-for-activitypub-settings-accordion-panel" hidden="hidden">
+				<p><?php \esc_html_e( 'Of course any other application in the Fediverse should work as well. Most applications support importing external content via searching for the contents full URL.', 'event-bridge-for-activitypub' ); ?></p>
+				<ol class="event-bridge-for-activitypub-settings-numbered-list">
+					<li><?php \esc_html_e( 'Log into your account on any Fediverse app.', 'event-bridge-for-activitypub' ); ?></li>
+					<li>
+						<?php \esc_html_e( 'In the search bar, type or copy the full URL of one of your event pages. For example:', 'event-bridge-for-activitypub' ); ?>
+						<code class="event-bridge-for-activitypub-settings-example-url"><?php echo \esc_url( $example_event_post ); ?></code>
+					</li>
+					<li><?php \esc_html_e( 'If the application which your are using natively supports ActivityPub events, you should see a representation of your WordPress event. If your application is supports receiving ActivityPub events you will get a post which summarizes the event. Keep in mind that some apps may not support events at all.', 'event-bridge-for-activitypub' ); ?></li>
+				</ol>
+			</div>
+			<h4 class="event-bridge-for-activitypub-settings-accordion-heading">
+				<button aria-expanded="false" class="event-bridge-for-activitypub-settings-accordion-trigger" aria-controls="event-bridge-for-activitypub-help-accordion-advanced" type="button">
+					<span class="title">
+						4. 
+						<img src="<?php echo esc_url( plugins_url( '/assets/img/activitypub.svg', EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE ) ); ?>" alt="Mastodon Icon" class="event-bridge-for-activitypub-settings-inline-icon">
+						<?php \esc_html_e( 'Advanced: Verifying the ActivityStreams JSON', 'event-bridge-for-activitypub' ); ?></span>
+					<span class="icon"></span>
+				</button>
+			</h4>
+			<div id="event-bridge-for-activitypub-help-accordion-advanced" class="event-bridge-for-activitypub-settings-accordion-panel" hidden="hidden">
+				<p>
+					<?php
+					// Assume $event_url contains the dynamic URL, and '?activitypub' is appended to it.
+					$activitypub_url = esc_url( $example_event_post . '?activitypub' );
+
+					// Prepare the activitypub part wrapped in a <code> element.
+					$activitypub_query = '<nobr><code>' . esc_html( '?activitypub' ) . '</code></nobr>';
+
+					$activitypub_url_html = '<a href="' . esc_url( $activitypub_url ) . '" target="_blank">' . esc_html( $activitypub_url ) . '</a>';
+
+					// Translator comment to explain the placeholder.
+					/* translators: %1$s is the <code>?activitypub</code> string, and %2$s is the full URL of an example event */
+					$raw_string = sprintf( __( 'For more technical users, you can inspect how your event is converted into an ActivityPub object. Simply append %1$s to the end of 	any single event pages URL to view the raw ActivityStreams JSON data (e.g., %2$s).', 'event-bridge-for-activitypub' ), $activitypub_query, $activitypub_url_html );
+
+					// Allowed HTML tags in the string (only <code> and <a>).
+					$allowed_html = array(
+						'a'    => array(
+							'href'   => array(),
+							'target' => array(),
+						),
+						'nobr' => array(),
+						'code' => array(),
+					);
+
+					// Output the formatted string with the allowed HTML elements.
+					echo wp_kses( $raw_string, $allowed_html );
+					?>
+				</p>
+			</div>
+		</div>
+	</div>
+
+	<div class="box">
+		<h2><?php \esc_html_e( 'Changelog', 'event-bridge-for-activitypub' ); ?></h2>
+		<pre>
+			<?php
+			$changelog = $wp_filesystem->get_contents( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . '/CHANGELOG.md' );
+			echo esc_html( substr( $changelog, strpos( $changelog, "\n", 180 ) + 1 ) );
+			?>
+		</pre>
+	</div>
+	<?php endif; ?>
+
+</div>
+

tests/bootstrap.php

@@ -0,0 +1,127 @@
+<?php
+/**
+ * PHPUnit bootstrap file.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+$_tests_dir = getenv( 'WP_TESTS_DIR' );
+
+if ( ! $_tests_dir ) {
+	$_tests_dir = rtrim( sys_get_temp_dir(), '/\\' ) . '/wordpress-tests-lib';
+}
+
+// Forward custom PHPUnit Polyfills configuration to PHPUnit bootstrap file.
+$_phpunit_polyfills_path = getenv( 'WP_TESTS_PHPUNIT_POLYFILLS_PATH' );
+if ( false !== $_phpunit_polyfills_path ) {
+	define( 'WP_TESTS_PHPUNIT_POLYFILLS_PATH', $_phpunit_polyfills_path );
+}
+
+if ( ! file_exists( "{$_tests_dir}/includes/functions.php" ) ) {
+	echo "Could not find {$_tests_dir}/includes/functions.php, have you run bin/install-wp-tests.sh ?" . PHP_EOL; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+	exit( 1 );
+}
+
+// Give access to tests_add_filter() function.
+require_once "{$_tests_dir}/includes/functions.php";
+
+/**
+ * Function to manually load an event plugin.
+ *
+ * @param string $plugin_file  The main plugin file of the event plugin.
+ */
+function _manually_load_event_plugin( $plugin_file ) {
+	$plugin_dir = ABSPATH . '/wp-content/plugins/';
+	require_once $plugin_dir . $plugin_file;
+	update_option( 'purchase_history_table_structure_migration_done', true );
+	$current   = get_option( 'active_plugins', array() );
+	$current[] = $plugin_file;
+	sort( $current );
+	update_option( 'active_plugins', $current );
+}
+
+/**
+ * Manually load the plugin being tested and its integrations.
+ */
+function _manually_load_plugin() {
+	$plugin_dir = ABSPATH . '/wp-content/plugins/';
+
+	// Always manually load the ActivityPub plugin.
+	require_once $plugin_dir . 'activitypub/activitypub.php';
+
+	// Capture the --filter argument.
+	$event_bridge_for_activitypub_integration_filter = null;
+	foreach ( $_SERVER['argv'] as $arg ) {
+		if ( strpos( $arg, '--filter=' ) === 0 ) {
+			$event_bridge_for_activitypub_integration_filter = substr( $arg, strlen( '--filter=' ) );
+			break;
+		}
+	}
+
+	// Hot fixes for eventin.
+	update_option( 'purchase_history_table_structure_migration_done', true );
+	update_option( 'etn_wizard', 'active' );
+
+	$plugin_file = null;
+	// See if we want to run integration tests for a specific event-plugin.
+	switch ( $event_bridge_for_activitypub_integration_filter ) {
+		case 'the_events_calendar':
+			$plugin_file = 'the-events-calendar/the-events-calendar.php';
+			break;
+		case 'vs_event_list':
+			$plugin_file = 'very-simple-event-list/vsel.php';
+			break;
+		case 'events_manager':
+			$plugin_file = 'events-manager/events-manager.php';
+			break;
+		case 'eventin':
+			$plugin_file = 'wp-event-solution/eventin.php';
+			break;
+		case 'modern_events_calendar_lite':
+			$plugin_file = 'modern-events-calendar-lite/modern-events-calendar-lite.php';
+			break;
+		case 'gatherpress':
+			$plugin_file = 'gatherpress/gatherpress.php';
+			break;
+		case 'wp_event_manager':
+			$plugin_file = 'wp-event-manager/wp-event-manager.php';
+			break;
+		case 'eventprime':
+			$plugin_file = 'eventprime-event-calendar-management/event-prime.php';
+			break;
+		case 'event_organiser':
+			$plugin_file = 'event-organiser/event-organiser.php';
+			break;
+	}
+
+	if ( $plugin_file ) {
+		_manually_load_event_plugin( $plugin_file );
+	} else {
+		// For all other tests we mainly use the Events Calendar as a reference.
+		_manually_load_event_plugin( 'the-events-calendar/the-events-calendar.php' );
+		_manually_load_event_plugin( 'very-simple-event-list/vsel.php' );
+
+	}
+
+	// Hot fix that allows using Events Manager within unit tests, because the em_init() is later not run as admin.
+	if ( 'events_manager' === $event_bridge_for_activitypub_integration_filter ) {
+		require_once $plugin_dir . 'events-manager/em-install.php';
+		em_create_events_table();
+		em_create_events_meta_table();
+		em_create_locations_table();
+	}
+
+	if ( 'modern_events_calendar_lite' === $event_bridge_for_activitypub_integration_filter ) {
+		require_once $plugin_dir . 'modern-events-calendar-lite/app/libraries/factory.php';
+		$mec_factory = new MEC_factory();
+		$mec_factory->install();
+	}
+
+	// At last manually load our WordPress plugin.
+	require dirname( __DIR__ ) . '/event-bridge-for-activitypub.php';
+}
+
+tests_add_filter( 'muplugins_loaded', '_manually_load_plugin' );
+
+// Start up the WP testing environment.
+require "{$_tests_dir}/includes/bootstrap.php";

tests/test-class-activitypub-event-bridge-shortcodes.php

@@ -0,0 +1,193 @@
+<?php
+/**
+ * Test file for Activitypub Shortcodes.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @license AGPL-3.0-or-later
+ */
+
+use Activitypub\Shortcodes;
+
+/**
+ * Test class for Activitypub Shortcodes.
+ *
+ * @coversDefaultClass \Activitypub\Shortcodes
+ */
+class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! class_exists( '\Tribe__Events__Main' ) ) {
+			self::markTestSkipped( 'The Events Calendar plugin is needed to test Event Shortcodes' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test the shortcode for rendering the events start time.
+	 */
+	public function test_start_time() {
+		// Create a The Events Calendar Event without content.
+		$wp_object = tribe_events()
+			->set_args( Test_The_Events_Calendar::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+			return;
+		}
+
+		$transformer->register_shortcodes();
+
+		$summary = '[ap_start_time]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '🗓️ Start: December 1, 2024 3:00 pm', $summary );
+
+		$summary = '[ap_start_time icon="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'Start: December 1, 2024 3:00 pm', $summary );
+
+		$summary = '[ap_start_time icon="false" label="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'December 1, 2024 3:00 pm', $summary );
+
+		$transformer->unregister_shortcodes();
+	}
+
+	/**
+	 * Test the shortcode for rendering the events end time.
+	 */
+	public function test_end_time() {
+		// Create a The Events Calendar Event without content.
+		$wp_object = tribe_events()
+			->set_args( Test_The_Events_Calendar::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+			return;
+		}
+
+		$transformer->register_shortcodes();
+
+		$summary = '[ap_end_time]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '⏳ End: December 1, 2024 4:00 pm', $summary );
+
+		$summary = '[ap_end_time icon="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'End: December 1, 2024 4:00 pm', $summary );
+
+		$summary = '[ap_end_time icon="false" label="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'December 1, 2024 4:00 pm', $summary );
+
+		$transformer->unregister_shortcodes();
+	}
+
+	/**
+	 * Test the shortcode for rendering the events location when no location is set.
+	 */
+	public function test_location_when_no_location_is_set() {
+		// Create a The Events Calendar Event without content.
+		$wp_object = tribe_events()
+			->set_args( Test_The_Events_Calendar::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+			return;
+		}
+
+		$transformer->register_shortcodes();
+
+		$summary = '[ap_location]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '', $summary );
+
+		$transformer->unregister_shortcodes();
+	}
+
+	/**
+	 * Test the shortcode for rendering the events location when location is set.
+	 */
+	public function test_location_when_location_is_set() {
+		// Create Venue.
+		$venue = tribe_venues()->set_args( Test_The_Events_Calendar::MOCKUP_VENUS['minimal_venue'] )->create();
+		// Create a The Events Calendar Event.
+		$wp_object = tribe_events()
+			->set_args( Test_The_Events_Calendar::MOCKUP_EVENTS['complex_event'] )
+			->set( 'venue', $venue->ID )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+			return;
+		}
+
+		$transformer->register_shortcodes();
+
+		$summary = '[ap_location]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '📍 Location: Minimal Venue', $summary );
+
+		$summary = '[ap_location icon="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'Location: Minimal Venue', $summary );
+
+		$summary = '[ap_location icon="false" label="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( 'Minimal Venue', $summary );
+
+		$transformer->unregister_shortcodes();
+	}
+
+	/**
+	 * Test the shortcode for rendering the events location when location with detailed address is set.
+	 */
+	public function test_location_when_detailed_location_is_set() {
+		// Create Venue.
+		$venue = tribe_venues()->set_args( Test_The_Events_Calendar::MOCKUP_VENUS['complex_venue'] )->create();
+		// Create a The Events Calendar Event.
+		$wp_object = tribe_events()
+			->set_args( Test_The_Events_Calendar::MOCKUP_EVENTS['complex_event'] )
+			->set( 'venue', $venue->ID )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+			return;
+		}
+
+		$transformer->register_shortcodes();
+
+		$summary = '[ap_location]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '📍 Location: Complex Venue, Venue address, Venue zip, Venue city, Venue country', $summary );
+
+		$summary = '[ap_location country="false"]';
+		$summary = do_shortcode( $summary );
+		$this->assertEquals( '📍 Location: Complex Venue, Venue address, Venue zip, Venue city', $summary );
+
+		$transformer->unregister_shortcodes();
+	}
+}

tests/test-class-plugin-event-organiser.php

@@ -0,0 +1,153 @@
+<?php
+/**
+ * Test class for the integration of the Event Organiser.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_Event_Organiser extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! function_exists( 'eo_get_events' ) ) {
+			self::markTestSkipped( 'Event Organiser plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Run the install script just in time which makes sure the custom tables exist and more.
+		eventorganiser_install();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'event', get_option( 'activitypub_support_post_types' ) );
+
+		$event_data = array(
+			'start'    => new DateTime( '+10 days 15:00:00', eo_get_blog_timezone() ),
+			'end'      => new DateTime( '+10 days 16:00:00', eo_get_blog_timezone() ),
+			'all_day'  => 0,
+			'schedule' => 'once',
+		);
+
+		$post_data = array(
+			'post_title'   => 'Unit Test Event',
+			'post_content' => 'Unit Test description.',
+			'post_status'  => 'publish',
+		);
+
+		$post_id = eo_insert_event( $post_data, $event_data );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event_Organiser::class, $transformer );
+	}
+
+	/**
+	 * Test transformation to ActivityPub for basic event.
+	 */
+	public function test_transform_of_basic_event() {
+		// Mock Event.
+		$event_data = array(
+			'start'    => new DateTime( '+10 days 15:00:00', eo_get_blog_timezone() ),
+			'end'      => new DateTime( '+10 days 16:00:00', eo_get_blog_timezone() ),
+			'all_day'  => 0,
+			'schedule' => 'once',
+		);
+
+		$post_data = array(
+			'post_title'   => 'Unit Test Event',
+			'post_content' => 'Unit Test description.',
+			'post_status'  => 'publish',
+		);
+
+		$post_id = eo_insert_event( $post_data, $event_data );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Unit Test Event', $event_array['name'] );
+		$this->assertEquals( 'Unit Test description.', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+	}
+
+	/**
+	 * Test transformation to ActivityPub for event with location.
+	 */
+	public function test_transform_of_event_with_location() {
+		// Create venue.
+		$venue_args = array(
+			'description' => 'This is a test venue for the Fediverse.',
+			'address'     => 'Fediverse-Street 1337',
+			'city'        => 'Fediverse-Town',
+			'state'       => 'Fediverse-Sate',
+			'postcode'    => '1337',
+			'country'     => 'Fediverse-Country',
+			'latitude'    => 7.076668,
+			'longitude'   => 15.421371,
+		);
+		$venue_name = 'Fediverse Venue';
+		$venue      = eo_insert_venue( $venue_name, $venue_args );
+
+		// Mock Event.
+		$event_data = array(
+			'start'    => new DateTime( '+10 days 15:00:00', eo_get_blog_timezone() ),
+			'end'      => new DateTime( '+10 days 16:00:00', eo_get_blog_timezone() ),
+			'all_day'  => 0,
+			'schedule' => 'once',
+		);
+		$post_data  = array(
+			'post_title'   => 'Unit Test Event',
+			'post_content' => 'Unit Test description.',
+			'post_status'  => 'publish',
+		);
+		$post_id    = eo_insert_event( $post_data, $event_data );
+		wp_set_object_terms( $post_id, $venue['term_id'], 'event-venue' );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Unit Test Event', $event_array['name'] );
+		$this->assertEquals( 'Unit Test description.', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( $venue_args['description'], wp_strip_all_tags( $event_array['location']['content'] ) );
+		$this->assertEquals( $venue_args['address'], $event_array['location']['address']['streetAddress'] );
+		$this->assertEquals( $venue_args['city'], $event_array['location']['address']['addressLocality'] );
+		$this->assertEquals( $venue_args['state'], $event_array['location']['address']['addressRegion'] );
+		$this->assertEquals( $venue_args['country'], $event_array['location']['address']['addressCountry'] );
+		$this->assertEquals( $venue_args['postcode'], $event_array['location']['address']['postalCode'] );
+		$this->assertEquals( $venue_name, $event_array['location']['name'] );
+	}
+}

tests/test-class-plugin-eventin.php

@@ -0,0 +1,175 @@
+<?php
+/**
+ * Tests for WP Event Solution.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Test cases for WP Event Solution.
+ */
+class Test_Eventin extends WP_UnitTestCase {
+	/**
+	 * Basic Mock-up event.
+	 */
+	private function get_mockup_event(): array {
+		return array(
+			'post_status'    => 'publish',
+			'post_title'     => 'Eventin Test Event Title',
+			'post_content'   => 'Eventin Test Event Description',
+			'etn_start_date' => \gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ),
+			'etn_end_date'   => \gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ),
+			'etn_start_time' => \gmdate( 'H:i', strtotime( '+10 days 15:00:00' ) ),
+			'etn_end_time'   => \gmdate( 'H:i', strtotime( '+10 days 16:00:00' ) ),
+			'event_timezone' => 'Europe/Vienna',
+		);
+	}
+
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! class_exists( '\Wpeventin' ) ) {
+			self::markTestSkipped( 'Eventin plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_eventin_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'etn', get_option( 'activitypub_support_post_types' ) );
+
+		// Create a Eventin Event without content.
+		$event = new \Etn\Core\Event\Event_Model();
+		$event->create( $this->get_mockup_event() );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->id ) );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Eventin::class, $transformer );
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_eventin_test_minimal_event() {
+		// Create a Eventin Event without content.
+		$event = new \Etn\Core\Event\Event_Model();
+		$event->create( $this->get_mockup_event() );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->id ) )->to_object()->to_array();
+
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Eventin Test Event Title', $event_array['name'] );
+		$this->assertEquals( 'Eventin Test Event Description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 15:00:00' ) ), $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 16:00:00' ) ), $event_array['endTime'] );
+		$this->assertEquals( 'Europe/Vienna', $event_array['timezone'] );
+		$this->assertEquals( comments_open( $event->id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $event->id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertEquals( false, $event_array['isOnline'] );
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_eventin_test_online_event_with_custom_link() {
+		// Create a Eventin Event without content.
+		$event = new \Etn\Core\Event\Event_Model();
+		$args  = array_merge(
+			$this->get_mockup_event(),
+			array(
+				'event_type' => 'online',
+				'location'   => array(
+					'integration' => 'custom_url',
+					'custom_url'  => 'https://jit.si/eventmeeting',
+				),
+			)
+		);
+		$event->create( $args );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->id ) )->to_object()->to_array();
+
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Eventin Test Event Title', $event_array['name'] );
+		$this->assertEquals( 'Eventin Test Event Description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 15:00:00' ) ), $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 16:00:00' ) ), $event_array['endTime'] );
+		$this->assertEquals( 'Europe/Vienna', $event_array['timezone'] );
+		$this->assertEquals( comments_open( $event->id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $event->id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertEquals( true, $event_array['isOnline'] );
+		$this->assertContains(
+			array(
+				'type'      => 'Link',
+				'mediaType' => 'text/html',
+				'name'      => 'https://jit.si/eventmeeting',
+				'href'      => 'https://jit.si/eventmeeting',
+			),
+			$event_array['attachment']
+		);
+	}
+
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_eventin_test_online_event_with_physical_location() {
+		// Create a Eventin Event without content.
+		$event = new \Etn\Core\Event\Event_Model();
+		$args  = array_merge(
+			$this->get_mockup_event(),
+			array(
+				'event_type' => 'offline',
+				'location'   => array(
+					'address' => 'The NlNet center',
+				),
+			)
+		);
+		$event->create( $args );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->id ) )->to_object()->to_array();
+
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Eventin Test Event Title', $event_array['name'] );
+		$this->assertEquals( 'Eventin Test Event Description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 15:00:00' ) ), $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 16:00:00' ) ), $event_array['endTime'] );
+		$this->assertEquals( 'Europe/Vienna', $event_array['timezone'] );
+		$this->assertEquals( comments_open( $event->id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $event->id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertEquals( false, $event_array['isOnline'] );
+		$this->assertEquals( 'The NlNet center', $event_array['location']['address'] );
+		$this->assertEquals( 'The NlNet center', $event_array['location']['name'] );
+	}
+}

tests/test-class-plugin-events-manger.php

@@ -0,0 +1,184 @@
+<?php
+/**
+ * Class SampleTest
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_Events_Manager extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! class_exists( 'EM_Events' ) ) {
+			self::markTestSkipped( 'VS Event List plugin is not active.' );
+		}
+
+		// For tests allow every user to create new events.
+		update_option( 'dbem_events_anonymous_submissions', true );
+
+		// Make sure that ActivityPub support is enabled for Events Manager.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( EM_POST_TYPE_EVENT, get_option( 'activitypub_support_post_types' ) );
+
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'Events Manager Test event',
+				'post_status' => 'publish',
+				'post_type'   => EM_POST_TYPE_EVENT,
+				'meta_input'  => array(
+					'event_start_time' => strtotime( '+10 days 15:00:00' ),
+				),
+			)
+		);
+
+		$wp_object = get_post( $wp_post_id );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Events_Manager::class, $transformer );
+	}
+
+	/**
+	 * Test the transformation of a minimal event.
+	 */
+	public function test_transform_of_minimal_event() {
+		// Create mockup event.
+		$event                   = new EM_Event();
+		$event->event_name       = 'Events Manager Test event';
+		$event->post_content     = 'Event description';
+		$event->event_start_date = gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) );
+		$event->event_start_time = '15:00:00';
+		$event->start            = strtotime( $event->event_start_date . ' ' . $event->event_start_time );
+		$event->force_status     = 'publish';
+		$event->event_rsvp       = false;
+		$this->assertTrue( $event->save() );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->post_id ) )->to_object()->to_array();
+
+		// Check that we got the right transformer.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Events Manager Test event', $event_array['name'] );
+		$this->assertEquals( 'Event description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( comments_open( $event->post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $event->post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertArrayNotHasKey( 'endTime', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+	}
+
+	/**
+	 * Test the transformation of a event with full location.
+	 */
+	public function test_transform_of__full_event_with_location() {
+		// Create a mockup location.
+		$location                    = new EM_Location();
+		$location->location_name     = 'Test location';
+		$location->location_address  = 'Test Address';
+		$location->location_town     = 'Test Town';
+		$location->location_state    = 'Test state';
+		$location->location_postcode = '1337';
+		$location->location_region   = 'Test region';
+		$location->location_country  = 'AT'; // Must be a two char country code.
+		$this->assertTrue( $location->save() );
+
+		// Create mockup event.
+		$event                   = new EM_Event();
+		$event->event_name       = 'Events Manager Test event';
+		$event->post_content     = 'Event description';
+		$event->location_id      = $location->location_id;
+		$event->event_start_date = gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) );
+		$event->event_end_date   = gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) );
+		$event->event_start_time = '15:00:00';
+		$event->event_end_time   = '16:00:00';
+		$event->start            = strtotime( $event->event_start_date . ' ' . $event->event_start_time );
+		$event->end              = strtotime( $event->event_end_date . ' ' . $event->event_end_time );
+		$event->force_status     = 'publish';
+		$event->event_rsvp       = false;
+		$this->assertTrue( $event->save() );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->post_id ) )->to_object()->to_array();
+
+		// Check that we got the right transformer.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Events Manager Test event', $event_array['name'] );
+		$this->assertEquals( 'Event description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'Test location', $event_array['location']['name'] );
+		$this->assertEquals( 'Test Address', $event_array['location']['address']['postalAddress'] );
+		$this->assertEquals( 'Test Town', $event_array['location']['address']['addressLocality'] );
+		$this->assertEquals( 'Test state', $event_array['location']['address']['addressRegion'] );
+		$this->assertEquals( '1337', $event_array['location']['address']['postalCode'] );
+		$this->assertEquals( 'AT', $event_array['location']['address']['addressCountry'] );
+	}
+
+	/**
+	 * Test the transformation of a minimal event.
+	 */
+	public function test_transform_of_event_with_name_only_location() {
+		// Create a mockup location.
+		$location                = new EM_Location();
+		$location->location_name = 'Name only location';
+		$this->assertTrue( $location->save() );
+
+		// Create mockup event.
+		$event                   = new EM_Event();
+		$event->event_name       = 'Events Manager Test event';
+		$event->post_content     = 'Event description';
+		$event->location_id      = $location->location_id;
+		$event->event_start_date = gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) );
+		$event->event_end_date   = gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) );
+		$event->event_start_time = '15:00:00';
+		$event->event_end_time   = '16:00:00';
+		$event->start            = strtotime( $event->event_start_date . ' ' . $event->event_start_time );
+		$event->end              = strtotime( $event->event_end_date . ' ' . $event->event_end_time );
+		$event->force_status     = 'publish';
+		$event->event_rsvp       = false;
+		$this->assertTrue( $event->save() );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->post_id ) )->to_object()->to_array();
+
+		// Check that we got the right transformer.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Events Manager Test event', $event_array['name'] );
+		$this->assertEquals( 'Event description', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'Name only location', $event_array['location']['name'] );
+	}
+}

tests/test-class-plugin-gatherpress.php

@@ -0,0 +1,104 @@
+<?php
+/**
+ * Class SampleTest
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_GatherPress extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! defined( 'GATHERPRESS_CORE_FILE' ) ) {
+			self::markTestSkipped( 'GatherPress plugin is not active.' );
+		}
+
+		// Mock the plugin activation.
+		GatherPress\Core\Setup::get_instance()->activate_gatherpress_plugin( false );
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'gatherpress_event', get_option( 'activitypub_support_post_types' ) );
+
+		// Mock GatherPress Event.
+		$post_id = wp_insert_post(
+			array(
+				'post_title'   => 'Unit Test Event',
+				'post_type'    => 'gatherpress_event',
+				'post_content' => 'Unit Test description.',
+				'post_status'  => 'publish',
+			)
+		);
+		$event   = new \GatherPress\Core\Event( $post_id );
+		$params  = array(
+			'datetime_start' => '+10 days 15:00:00',
+			'datetime_end'   => '+10 days 16:00:00',
+			'timezone'       => \wp_timezone_string(),
+		);
+
+		$event->save_datetimes( $params );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $event->event );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\GatherPress::class, $transformer );
+	}
+
+	/**
+	 * Test transformation to ActivityPUb for basic event.
+	 */
+	public function test_transform_of_basic_event() {
+		// Mock GatherPress Event.
+		$post_id = wp_insert_post(
+			array(
+				'post_title'   => 'Unit Test Event',
+				'post_type'    => 'gatherpress_event',
+				'post_content' => 'Unit Test description.',
+				'post_status'  => 'publish',
+			)
+		);
+		$event   = new \GatherPress\Core\Event( $post_id );
+		$params  = array(
+			'datetime_start' => '+10 days 15:00:00',
+			'datetime_end'   => '+10 days 16:00:00',
+			'timezone'       => \wp_timezone_string(),
+		);
+		$event->save_datetimes( $params );
+
+		// Call the transformer Factory.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $event->event )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'Unit Test Event', $event_array['name'] );
+		$this->assertEquals( 'Unit Test description.', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+	}
+}

tests/test-class-plugin-modern-events-calendar-lite.php

@@ -0,0 +1,185 @@
+<?php
+/**
+ * Tests or Modern Events Calendar Lite
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_Modern_Events_Calendar_Lite extends WP_UnitTestCase {
+	/**
+	 * The MEC main instance.
+	 *
+	 * @var \MEC_main|null
+	 */
+	protected $mec_main;
+
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! class_exists( '\MEC' ) ) {
+			self::markTestSkipped( 'Modern Events Calendar Lite is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		$this->mec_main = \MEC::getInstance( 'app.libraries.main' );
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_modern_events_calendar_lite_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'mec-events', get_option( 'activitypub_support_post_types' ) );
+
+		// Insert a new Event.
+		$event = array(
+			'title'              => 'MEC Test Event',
+			'status'             => 'publish',
+			'start_time_hour'    => '3',
+			'start_time_minutes' => '00',
+			'start_time_ampm'    => 'PM',
+			'start'              => '2025-01-01',
+			'end'                => '2025-01-01',
+			'end_time_hour'      => '4',
+			'end_time_minutes'   => '00',
+			'end_time_ampm'      => 'PM',
+			'repeat_status'      => 0,
+			'repeat_type'        => 'daily',
+			'interval'           => 1,
+		);
+
+		$post_id = $this->mec_main->save_event( $event );
+
+		$wp_object = get_post( $post_id );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Modern_Events_Calendar_Lite::class, $transformer );
+	}
+
+	/**
+	 * Test that the transformation of minimal event.
+	 */
+	public function test_modern_events_calendar_lite_minimal_event() {
+		$start_timestamp = strtotime( '+10 days 15:00:00' );
+		$end_timestamp   = strtotime( '+10 days 16:00:00' );
+
+		// Insert a new Event.
+		$event = array(
+			'title'              => 'MEC Test Event',
+			'status'             => 'publish',
+			'content'            => 'This is the content of the MEC!',
+			'start_time_hour'    => gmdate( 'h', $start_timestamp ),
+			'start_time_minutes' => gmdate( 'i', $start_timestamp ),
+			'start_time_ampm'    => gmdate( 'A', $start_timestamp ),
+			'start'              => gmdate( 'Y-m-d', $start_timestamp ),
+			'end'                => gmdate( 'Y-m-d', $end_timestamp ),
+			'end_time_hour'      => gmdate( 'h', $end_timestamp ),
+			'end_time_minutes'   => gmdate( 'i', $end_timestamp ),
+			'end_time_ampm'      => gmdate( 'A', $end_timestamp ),
+			'repeat_status'      => 0,
+			'repeat_type'        => 'daily',
+			'interval'           => 1,
+		);
+
+		$post_id = $this->mec_main->save_event( $event );
+
+		$wp_object = get_post( $post_id );
+
+		// Call the transformer to make the ActivityStreams representation of the event.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'MEC Test Event', $event_array['name'] );
+		$this->assertEquals( 'This is the content of the MEC!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertTrue( $event_array['commentsEnabled'] );
+		$this->assertEquals( 'allow_all', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( get_permalink( $wp_object ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+	}
+
+	/**
+	 * Test that the transformation of minimal event.
+	 */
+	public function test_modern_events_calendar_lite_event_with_location() {
+		$start_timestamp = strtotime( '+10 days 15:00:00' );
+		$end_timestamp   = strtotime( '+10 days 16:00:00' );
+
+		// Add new location.
+		$location = array(
+			'name'      => 'MEC Location',
+			'latitude'  => '52.356370',
+			'longitude' => '4.955760',
+			'address'   => 'Stichting NLnet, Science Park 400, 1098 XH Amsterdam',
+			'url'       => 'https://nlnet.nl/',
+		);
+
+		$location_id = $this->mec_main->save_location( $location );
+
+		// Insert a new Event.
+		$event = array(
+			'title'              => 'MEC Test Event',
+			'status'             => 'publish',
+			'content'            => 'This is the content of the MEC!',
+			'start_time_hour'    => gmdate( 'h', $start_timestamp ),
+			'start_time_minutes' => gmdate( 'i', $start_timestamp ),
+			'start_time_ampm'    => gmdate( 'A', $start_timestamp ),
+			'start'              => gmdate( 'Y-m-d', $start_timestamp ),
+			'end'                => gmdate( 'Y-m-d', $end_timestamp ),
+			'end_time_hour'      => gmdate( 'h', $end_timestamp ),
+			'end_time_minutes'   => gmdate( 'i', $end_timestamp ),
+			'end_time_ampm'      => gmdate( 'A', $end_timestamp ),
+			'repeat_status'      => 0,
+			'repeat_type'        => 'daily',
+			'interval'           => 1,
+			'location_id'        => $location_id,
+		);
+
+		$post_id = $this->mec_main->save_event( $event );
+
+		$wp_object = get_post( $post_id );
+
+		// Call the transformer to make the ActivityStreams representation of the event.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'MEC Test Event', $event_array['name'] );
+		$this->assertEquals( 'This is the content of the MEC!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertTrue( $event_array['commentsEnabled'] );
+		$this->assertEquals( 'allow_all', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( get_permalink( $wp_object ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertEquals( $location['address'], $event_array['location']['address'] );
+		$this->assertEquals( $location['name'], $event_array['location']['name'] );
+		$this->assertEquals( $location['latitude'], $event_array['location']['latitude'] );
+		$this->assertEquals( $location['longitude'], $event_array['location']['longitude'] );
+	}
+}

tests/test-class-plugin-the-events-calendar.php

@@ -0,0 +1,216 @@
+<?php
+/**
+ * Class SampleTest
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_The_Events_Calendar extends WP_UnitTestCase {
+	/**
+	 * Mockup events of certain complexity.
+	 */
+	public const MOCKUP_VENUS = array(
+		'minimal_venue' => array(
+			'venue'  => 'Minimal Venue',
+			'status' => 'publish',
+		),
+		'complex_venue' => array(
+			'venue'         => 'Complex Venue',
+			'status'        => 'publish',
+			'show_map'      => false,
+			'show_map_link' => false,
+			'address'       => 'Venue address',
+			'city'          => 'Venue city',
+			'country'       => 'Venue country',
+			'province'      => 'Venue province',
+			'state'         => 'Venue state',
+			'stateprovince' => 'Venue stateprovince',
+			'zip'           => 'Venue zip',
+			'phone'         => 'Venue phone',
+			'website'       => 'http://venue.com',
+		),
+	);
+
+	public const MOCKUP_EVENTS = array(
+		'minimal_event' => array(
+			'title'      => 'My Event',
+			'content'    => 'Come to my event!',
+			'start_date' => '+10 days 15:00:00',
+			'duration'   => HOUR_IN_SECONDS,
+			'status'     => 'publish',
+		),
+		'complex_event' => array(
+			'title'      => 'My Event',
+			'content'    => 'Come to my event!',
+			'start_date' => '+10 days 15:00:00',
+			'duration'   => HOUR_IN_SECONDS,
+			'status'     => 'publish',
+		),
+	);
+
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! class_exists( '\Tribe__Events__Main' ) ) {
+			self::markTestSkipped( 'The Events Calendar plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_the_events_calendar_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'tribe_events', get_option( 'activitypub_support_post_types' ) );
+
+		// Create a The Events Calendar Event without content.
+		$wp_object = tribe_events()
+			->set_args( self::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\The_Events_Calendar::class, $transformer );
+	}
+
+	/**
+	 * Test transformation of minimal event without venue.
+	 */
+	public function test_transform_of_minimal_event_without_venue() {
+		// Create a The Events Calendar Event.
+		$wp_object = tribe_events()
+			->set_args( self::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'My Event', $event_array['name'] );
+		$this->assertEquals( 'Come to my event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertTrue( $event_array['commentsEnabled'] );
+		$this->assertEquals( 'allow_all', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+	}
+
+	/**
+	 * Test transformation of event with mapped category.
+	 */
+	public function test_transform_event_with_mapped_categories() {
+		// Create category.
+		$category_id_music   = wp_insert_term( 'Music', Tribe__Events__Main::TAXONOMY, array( 'slug' => 'music' ) );
+		$category_id_theatre = wp_insert_term( 'Theatre', Tribe__Events__Main::TAXONOMY, array( 'slug' => 'theatre' ) );
+
+		// Set default mapping for event categories.
+		update_option( 'event_bridge_for_activitypub_default_event_category', 'MUSIC' );
+
+		// Set an override for the category with the slug theatre.
+		update_option( 'event_bridge_for_activitypub_event_category_mappings', array( 'theatre' => 'THEATRE' ) );
+
+		// Create a The Events Calendar event with the music category.
+		$wp_object = tribe_events()
+			->set_args( self::MOCKUP_EVENTS['minimal_event'] )
+			->create();
+		// Set the post term music to the event.
+		wp_set_post_terms( $wp_object->ID, $category_id_music['term_id'], Tribe__Events__Main::TAXONOMY );
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+		// See if the default category mapping is applied.
+		$this->assertEquals( 'MUSIC', $event_array['category'] );
+
+		// Set the post term theatre to the event.
+		wp_set_post_terms( $wp_object->ID, $category_id_theatre['term_id'], Tribe__Events__Main::TAXONOMY, false );
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+		// See if the default category mapping is applied.
+		$this->assertEquals( 'THEATRE', $event_array['category'] );
+	}
+
+	/**
+	 * Test transformation of  minimal event with minimal venue.
+	 */
+	public function test_transform_of_minimal_event_with_venue() {
+		// Create Venue.
+		$venue = tribe_venues()->set_args( self::MOCKUP_VENUS['minimal_venue'] )->create();
+		// Create a The Events Calendar Event.
+		$wp_object = tribe_events()
+			->set_args( self::MOCKUP_EVENTS['complex_event'] )
+			->set( 'venue', $venue->ID )
+			->create();
+
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'My Event', $event_array['name'] );
+		$this->assertEquals( 'Come to my event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['commentsEnabled'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'Place', $event_array['location']['type'] );
+		$this->assertEquals( self::MOCKUP_VENUS['minimal_venue']['venue'], $event_array['location']['name'] );
+	}
+
+	/**
+	 * Test transformation of  minimal event with fully filled venue.
+	 */
+	public function test_transform_of_minimal_event_with_address_venue() {
+		// Create Venue.
+		$venue = tribe_venues()->set_args( self::MOCKUP_VENUS['complex_venue'] )->create();
+		// Create a The Events Calendar Event.
+		$wp_object = tribe_events()
+			->set_args( self::MOCKUP_EVENTS['minimal_event'] )
+			->set( 'venue', $venue->ID )
+			->create();
+
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'My Event', $event_array['name'] );
+		$this->assertEquals( 'Come to my event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['commentsEnabled'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'Place', $event_array['location']['type'] );
+		$this->assertEquals( 'PostalAddress', $event_array['location']['address']['type'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['venue'], $event_array['location']['name'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['venue'], $event_array['location']['address']['name'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['province'], $event_array['location']['address']['addressRegion'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['address'], $event_array['location']['address']['streetAddress'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['city'], $event_array['location']['address']['addressLocality'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['country'], $event_array['location']['address']['addressCountry'] );
+		$this->assertEquals( self::MOCKUP_VENUS['complex_venue']['zip'], $event_array['location']['address']['postalCode'] );
+	}
+}

tests/test-class-plugin-vs-event-list.php

@@ -0,0 +1,211 @@
+<?php
+/**
+ * Class SampleTest
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_VS_Event_List extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! function_exists( 'vsel_custom_post_type' ) ) {
+			self::markTestSkipped( 'VS Event List plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'event', get_option( 'activitypub_support_post_types' ) );
+
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'VSEL Test Event',
+				'post_status' => 'publish',
+				'post_type'   => 'event',
+				'meta_input'  => array(
+					'event-start-date' => strtotime( '+10 days 15:00:00' ),
+				),
+			)
+		);
+
+		$wp_object = get_post( $wp_post_id );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\VS_Event_List::class, $transformer );
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of minimal event.
+	 */
+	public function test_transform_of_minimal_event() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'VSEL Test Event',
+				'post_status' => 'publish',
+				'post_type'   => 'event',
+				'meta_input'  => array(
+					'event-start-date' => strtotime( '+10 days 15:00:00' ),
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'VSEL Test Event', $event_array['name'] );
+		$this->assertEquals( '', $event_array['content'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertArrayNotHasKey( 'endTime', $event_array );
+		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of minimal event.
+	 */
+	public function test_transform_of_full_event() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'VSEL Test Event',
+				'post_status' => 'publish',
+				'post_type'   => 'event',
+				'meta_input'  => array(
+					'event-start-date' => strtotime( '+10 days 15:00:00' ),
+					'event-date'       => strtotime( '+10 days 16:00:00' ),
+					'event-link'       => 'https://event-federation.eu/vsel-test-event',
+					'event-link-label' => 'Website',
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'VSEL Test Event', $event_array['name'] );
+		$this->assertEquals( '', $event_array['content'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertContains(
+			array(
+				'type'      => 'Link',
+				'name'      => 'Website',
+				'href'      => 'https://event-federation.eu/vsel-test-event',
+				'mediaType' => 'text/html',
+			),
+			$event_array['attachment']
+		);
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of event with hidden end time.
+	 */
+	public function test_transform_of_event_with_hidden_end_time() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'VSEL Test Event',
+				'post_status' => 'publish',
+				'post_type'   => 'event',
+				'meta_input'  => array(
+					'event-start-date'    => strtotime( '+10 days 15:00:00' ),
+					'event-date'          => strtotime( '+10 days 16:00:00' ),
+					'event-hide-end-time' => 'yes',
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertArrayNotHasKey( 'endTime', $event_array );
+	}
+
+	/**
+	 * Test transformation of event with mapped category.
+	 */
+	public function test_transform_event_with_mapped_categories() {
+		// Create category.
+		$category_id_music   = wp_insert_term( 'Music', 'event_cat', array( 'slug' => 'music' ) );
+		$category_id_theatre = wp_insert_term( 'Theatre', 'event_cat', array( 'slug' => 'theatre' ) );
+
+		// Set default mapping for event categories.
+		update_option( 'event_bridge_for_activitypub_default_event_category', 'MUSIC' );
+
+		// Set an override for the category with the slug theatre.
+		update_option( 'event_bridge_for_activitypub_event_category_mappings', array( 'theatre' => 'THEATRE' ) );
+
+		// Create a VS Event List event with the music category.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'VSEL Test Event',
+				'post_status' => 'publish',
+				'post_type'   => 'event',
+				'meta_input'  => array(
+					'event-start-date'    => strtotime( '+10 days 15:00:00' ),
+					'event-date'          => strtotime( '+10 days 16:00:00' ),
+					'event-hide-end-time' => 'yes',
+				),
+			)
+		);
+		wp_set_post_terms( $wp_post_id, $category_id_music['term_id'], 'event_cat' );
+
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// See if the default category mapping is applied.
+		$this->assertEquals( 'MUSIC', $event_array['category'] );
+
+		// Change the event category to theatre.
+		wp_set_post_terms( $wp_post_id, $category_id_theatre['term_id'], 'event_cat', false );
+
+		// Call the transformer.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// See if the default category mapping is applied.
+		$this->assertEquals( 'THEATRE', $event_array['category'] );
+	}
+}

tests/test-class-plugin-wp-event-manager.php

@@ -0,0 +1,182 @@
+<?php
+/**
+ * Class SampleTest
+ *
+ * @package Event_Bridge_For_ActivityPub
+ */
+
+/**
+ * Sample test case.
+ */
+class Test_WP_Event_Manager extends WP_UnitTestCase {
+	/**
+	 * Override the setup function, so that tests don't run if the Events Calendar is not active.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		if ( ! function_exists( 'wp_event_manager_notify_new_user' ) ) {
+			self::markTestSkipped( 'WP Event Manager plugin is not active.' );
+		}
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		// Delete all posts afterwards.
+		_delete_all_posts();
+	}
+
+	/**
+	 * Test that the right transformer gets applied.
+	 */
+	public function test_transformer_class() {
+		// We only test for one event plugin being active at the same time,
+		// even though we support multiple onces in theory.
+		// But testing all combinations is beyond scope.
+		$active_event_plugins = \Event_Bridge_For_ActivityPub\Setup::get_instance()->get_active_event_plugins();
+		$this->assertEquals( 1, count( $active_event_plugins ) );
+
+		// Enable ActivityPub support for the event plugin.
+		$this->assertContains( 'event_listing', get_option( 'activitypub_support_post_types' ) );
+
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'  => 'WP Event Manager TestEvent',
+				'post_status' => 'publish',
+				'post_type'   => 'event_listing',
+				'meta_input'  => array(
+					'event-start-date' => strtotime( '+10 days 15:00:00' ),
+				),
+			)
+		);
+
+		$wp_object = get_post( $wp_post_id );
+
+		// Call the transformer Factory.
+		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
+
+		// Check that we got the right transformer.
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\WP_Event_Manager::class, $transformer );
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of minimal event.
+	 */
+	public function test_transform_of_minimal_event() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'   => 'WP Event Manager TestEvent',
+				'post_status'  => 'publish',
+				'post_type'    => 'event_listing',
+				'post_content' => 'Come to my WP Event Manager event!',
+				'meta_input'   => array(
+					'_event_start_date' => strtotime( '+10 days 15:00:00' ),
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'WP Event Manager TestEvent', $event_array['name'] );
+		$this->assertEquals( 'Come to my WP Event Manager event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertArrayNotHasKey( 'endTime', $event_array );
+		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of minimal event.
+	 */
+	public function test_transform_of_full_online_event() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'   => 'WP Event Manager TestEvent',
+				'post_status'  => 'publish',
+				'post_type'    => 'event_listing',
+				'post_content' => 'Come to my WP Event Manager event!',
+				'meta_input'   => array(
+					'_event_start_date' => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 15:00:00' ) ),
+					'_event_end_date'   => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 16:00:00' ) ),
+					'_event_video_url'  => 'https://event-federation.eu/meeting-room',
+					'_event_online'     => 'yes',
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'WP Event Manager TestEvent', $event_array['name'] );
+		$this->assertEquals( 'Come to my WP Event Manager event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( true, $event_array['isOnline'] );
+		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayNotHasKey( 'location', $event_array );
+		$this->assertEquals( 'MEETING', $event_array['category'] );
+		$this->assertContains(
+			array(
+				'type'      => 'Link',
+				'name'      => __( 'Video URL', 'event-bridge-for-activitypub' ),
+				'href'      => 'https://event-federation.eu/meeting-room',
+				'mediaType' => 'text/html',
+			),
+			$event_array['attachment']
+		);
+	}
+
+	/**
+	 * Test the transformation to ActivityStreams of minimal event.
+	 */
+	public function test_transform_of_event_with_location() {
+		// Insert a new Event.
+		$wp_post_id = wp_insert_post(
+			array(
+				'post_title'   => 'WP Event Manager TestEvent',
+				'post_status'  => 'publish',
+				'post_type'    => 'event_listing',
+				'post_content' => 'Come to my WP Event Manager event!',
+				'meta_input'   => array(
+					'_event_start_date' => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 15:00:00' ) ),
+					'_event_end_date'   => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 16:00:00' ) ),
+					'_event_location'   => 'Some text location',
+					'_event_online'     => 'no',
+				),
+			)
+		);
+
+		// Transform the event to ActivityStreams.
+		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
+
+		// Check that the event ActivityStreams representation contains everything as expected.
+		$this->assertEquals( 'Event', $event_array['type'] );
+		$this->assertEquals( 'WP Event Manager TestEvent', $event_array['name'] );
+		$this->assertEquals( 'Come to my WP Event Manager event!', wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'external', $event_array['joinMode'] );
+		$this->assertEquals( false, $event_array['isOnline'] );
+		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertArrayHasKey( 'location', $event_array );
+		$this->assertEquals( 'Some text location', $event_array['location']['address'] );
+	}
+}