add dot to plugin description

activitypub-event-extensions.php

@@ -1,7 +1,7 @@
 <?php
 /**
  * Plugin Name: ActivityPub Event Extensions
- * Description: Custom ActivityPub Transformers and Integretions for common Event Plugins
+ * Description: Custom ActivityPub Transformers and Integrations for common Event Plugins.
  * Plugin URI:  https://event-federation.eu/
  * Version:     1.0.0
  * Author:      André Menrath
@@ -9,90 +9,52 @@
  * Text Domain: activitypub-event-extensions
  * License:     AGPL-3.0-or-later
  *
- * ActivityPub tested up to: 2.2.0
+ * ActivityPub tested up to: 2.4.0
  *
  * @package activitypub-event-extensions
  * @license AGPL-3.0-or-later
  */
 
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly.
-}
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
-/**
- * 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;
-		}
+define( 'ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_VERSION', '1.0.0' );
 
-		/**
-		 * 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 );
-		}
+define( 'ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
+define( 'ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_BASENAME', plugin_basename( __FILE__ ) );
+define( 'ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_FILE', plugin_dir_path( __FILE__ ) . '/' . basename( __FILE__ ) );
+define( 'ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
 
-		/**
-		 * 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 );
-		}
+// Include and register the autoloader class for automatic loading of plugin classes.
+require_once ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_DIR . '/includes/class-autoloader.php';
+Activitypub_Event_Extensions\Autoloader::register();
 
-		/**
-		 * 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
-);
+// Initialize the plugin.
+Activitypub_Event_Extensions\Setup::get_instance();
 
 
-/**
- * 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();
+
+
+// For local development purposes: TODO. Remove everything after here.
 
 /**
  * Add a filter for http_request_host_is_external
  *
- * TODO: Remove this.
+ * TODO: Remove this for release.
  *
  * @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
+/**
+ * Add a filter for http_request_host_is_external
+ *
+ * TODO: Remove this for release.
+ *
+ * @todo This filter is temporary code needed to do local testing.
+ */
 function custom_http_request_host_is_external( $is_external, $host, $url ) {
 	$is_external = true;
 
@@ -102,7 +64,7 @@ function custom_http_request_host_is_external( $is_external, $host, $url ) {
 /**
  * Don't verify ssl certs for testing.
  *
- * TODO: Remove this.
+ * TODO: Remove this for release.
  *
  * @todo This filter is temporary code needed to do local testing.
  */

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,
-			)
-		);
-	}
-}

includes/activitypub/handler/class-join.php

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

includes/activitypub/transformer/class-event.php

@@ -0,0 +1,79 @@
+<?php
+/**
+ * Replace the default ActivityPub Transformer
+ *
+ * @package activity-event-transformers
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Activitypub_Event_Extensions\Activitypub\Transformer;
+
+use Activitypub\Activity\Extended_Object\Event as Event_Object;
+use Activitypub\Model\Blog;
+use Activitypub\Transformer\Post;
+
+use function Activitypub\get_rest_url_by_path;
+
+/**
+ * Base transformer for WordPress event post types to ActivityPub events.
+ */
+class Event extends Post {
+	/**
+	 * 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() {
+		$blog = new Blog();
+		return $blog->get_id();
+	}
+
+	/**
+	 * 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';
+	}
+
+	/**
+	 * Generic function that converts an WP-Event object to an ActivityPub-Event object.
+	 *
+	 * @return Event_Object
+	 */
+	public function to_object() {
+		$activitypub_object = new Event_Object();
+		$activitypub_object = $this->transform_object_properties( $activitypub_object );
+
+		$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(),
+			)
+		);
+		$path = sprintf( 'actors/%d/followers', intval( $this->wp_object->post_author ) );
+
+		$activitypub_object->set_to(
+			array(
+				'https://www.w3.org/ns/activitystreams#Public',
+				get_rest_url_by_path( $path ),
+			)
+		);
+
+		return $activitypub_object;
+	}
+}

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

@@ -7,11 +7,10 @@
  * @license AGPL-3.0-or-later
  */
 
+use Activitypub_Event_Extensions\Activitypub\Transformer\Event as Event_Transformer;
 use EM_Event;
 use Activitypub\Activity\Extended_Object\Event;
 use Activitypub\Activity\Extended_Object\Place;
-use Activitypub\Transformer\Post;
-
 use function Activitypub\esc_hashtag;
 
 if ( ! defined( 'ABSPATH' ) ) {
@@ -25,7 +24,7 @@ if ( ! defined( 'ABSPATH' ) ) {
  *
  * @since 1.0.0
  */
-class Events_Manager extends Post {
+class Events_Manager extends Event_Transformer {
 
 	/**
 	 * Holds the EM_Event object.
@@ -44,7 +43,6 @@ class Events_Manager extends Post {
 	 * @return string Widget name.
 	 */
 	public function get_transformer_name() {
-
 		return 'activitypub-event-transformers/events-manager';
 	}
 
@@ -58,7 +56,6 @@ class Events_Manager extends Post {
 	 * @return string Widget title.
 	 */
 	public function get_transformer_label() {
-
 		return 'Events Manager';
 	}
 
@@ -72,7 +69,6 @@ class Events_Manager extends Post {
 	 * @return array Widget categories.
 	 */
 	public static function get_supported_post_types() {
-
 		return array();
 	}
 
@@ -84,23 +80,19 @@ class Events_Manager extends Post {
 	 * @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() {
-
 		if ( 'url' === $this->em_event->event_location_type ) {
 			return null;
 		}
@@ -132,7 +124,6 @@ class Events_Manager extends Post {
 	 * Get the end time from the events metadata.
 	 */
 	protected function get_end_time() {
-
 		return null;
 	}
 
@@ -140,7 +131,6 @@ class Events_Manager extends Post {
 	 * Get the end time from the events metadata.
 	 */
 	protected function get_start_time() {
-
 		$date_string     = $this->em_event->event_start_date;
 		$time_string     = $this->em_event->event_start_time;
 		$timezone_string = $this->em_event->event_timezone;
@@ -157,7 +147,6 @@ class Events_Manager extends Post {
 	}
 
 	protected function get_maximum_attendee_capacity() {
-
 		return $this->em_event->event_spaces;
 	}
 
@@ -165,25 +154,21 @@ class Events_Manager extends Post {
 	 * @todo decide whether to include pending bookings or not!
 	 */
 	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 );
 		return $remaining_attendee_capacity;
 	}
 
 	protected function get_participant_count() {
-
 		$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 {
@@ -202,7 +187,6 @@ class Events_Manager extends Post {
 	// }
 
 	private function get_event_link_attachment() {
-
 		$event_link_url  = $this->em_event->event_location->data['url'];
 		$event_link_text = $this->em_event->event_location->data['text'];
 		return array(
@@ -218,7 +202,7 @@ 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.

includes/activitypub/transformer/class-gatherpress.php

@@ -8,7 +8,7 @@
 
 use Activitypub\Transformer\Post;
 use Activitypub\Model\Blog_user;
-use Activitypub\Activity\Extended_Object\Event;
+use Activitypub\Activity\Extended_Object\Event as Event_Object;
 use Activitypub\Activity\Extended_Object\Place;
 use GatherPress\Core\Event as GatherPress_Event;
 
@@ -26,7 +26,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 class GatherPress extends Post {
 
 	/**
-	 * The target transformet ActivityPub Event object.
+	 * The target ActivityPub Event object of the transformer.
 	 *
 	 * @var Event
 	 */

includes/activitypub/transformer/class-tribe.php

@@ -1,5 +1,4 @@
 <?php
-
 /**
  * ActivityPub Tribe Transformer
  *
@@ -7,20 +6,22 @@
  * @license AGPL-3.0-or-later
  */
 
+namespace Activitypub_Event_Extensions\Activitypub\Transformer;
+
 if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly.
 }
 
-use Activitypub\Transformer\Post;
-use Activitypub\Activity\Extended_Object\Event;
+use Activitypub_Event_Extensions\Activitypub\Transformer\Event;
 use Activitypub\Activity\Extended_Object\Place;
+use WP_Error;
 
 /**
  * ActivityPub Tribe Transformer
  *
  * @since 1.0.0
  */
-class Tribe extends Post {
+class Tribe extends Event {
 
 	/**
 	 * The Tribe Event object.
@@ -40,69 +41,14 @@ class Tribe extends 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
+		// TODO: make it possible that one event can have multiple categories?
+		// Using cat_slugs isn't the best 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 ) {
@@ -123,7 +69,7 @@ class Tribe extends Post {
 			return 'CANCELLED';
 		}
 		if ( 'postponed' === $this->tribe_event->event_status ) {
-			return 'CANCELLED'; // this will be reflected in the cancelled reason
+			return 'CANCELLED'; // This will be reflected in the cancelled reason.
 		}
 		if ( '' === $this->tribe_event->event_status ) {
 			return 'CONFIRMED';
@@ -142,12 +88,12 @@ class Tribe extends Post {
 	protected function get_content() {
 
 		$content = parent::get_content();
-		// todo remove link at the end of the content
+		// TODO: remove link at the end of the content.
 
-		// todo add organizer
-		// $this->tribe_event->organizers[0]
+		// TODO: add organizer
+		// $this->tribe_event->organizers[0].
 
-		// todo add Canclled reason in the content (maybe at the end)
+		// TODO: do add Cancelled reason in the content (maybe at the end).
 
 		return $content;
 	}
@@ -155,11 +101,12 @@ class Tribe extends Post {
 	/**
 	 * Get the event location.
 	 *
-	 * @param int $post_id The WordPress post ID.
 	 * @returns array The Place.
 	 */
 	public function get_event_location() {
 		/*
+		This is how the Tribe event looks like:
+		TODO: Remove this comment.
 			'post_title' => 'testvenue',
 			'post_name' => 'testvenue',
 			'guid' => 'http://localhost/venue/testvenue/',
@@ -184,6 +131,6 @@ class Tribe extends Post {
 				$venue->address . "\n" .
 							$venue->zip . ', ' . $venue->city . "\n" .
 							$venue->country
-			); // todo add checks that everything exists here (lol)
+			); // TODO: add checks that everything exists here.
 	}
 }

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

@@ -1,5 +1,4 @@
 <?php
-
 /**
  * ActivityPub Transformer for the plugin Very Simple Event List.
  *
@@ -7,11 +6,14 @@
  * @license AGPL-3.0-or-later
  */
 
-use Activitypub\Transformer\Post;
-use Activitypub\Model\Blog_user;
+namespace Activitypub_Event_Extensions\Activitypub\Transformer;
+
+use Activitypub_Event_Extensions\Activitypub\Transformer\Event as Event_Transformer;
+use Activitypub\Model\Blog;
 use Activitypub\Activity\Extended_Object\Event;
 use Activitypub\Activity\Extended_Object\Place;
 
+use WP_Error;
 use function Activitypub\get_rest_url_by_path;
 
 if ( ! defined( 'ABSPATH' ) ) {
@@ -23,7 +25,7 @@ if ( ! defined( 'ABSPATH' ) ) {
  *
  * @since 1.0.0
  */
-class VS_Event extends Post {
+class VS_Event extends Event_Transformer {
 
 	/**
 	 * The target transformet ActivityPub Event object.
@@ -89,7 +91,6 @@ class VS_Event extends Post {
 	/**
 	 * Get the event location.
 	 *
-	 * @param int $post_id The WordPress post ID.
 	 * @return array The Place.
 	 */
 	public function get_location() {
@@ -148,7 +149,7 @@ class VS_Event extends Post {
 		}
 		$event_link = $this->get_event_link();
 		if ( $event_link ) {
-			$attachments[] = $this->get_event_link();
+			$attachments[] = $event_link;
 		}
 		return $attachments;
 	}
@@ -159,62 +160,9 @@ class VS_Event extends Post {
 	 * @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.
 	 *
@@ -224,7 +172,6 @@ class VS_Event extends Post {
 	 * @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 ) ) {
@@ -315,7 +262,8 @@ class VS_Event extends Post {
 			->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();
+			->set_location()
+			->set_id();
 		return $this->ap_object;
 	}
 }

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

@@ -0,0 +1,93 @@
+<?php
+/**
+ * Class responsible for Event Plugin related admin notices.
+ *
+ * Notices for guiding to proper configuration of ActivityPub with event plugins.
+ *
+ * @package Activitypub_Event_Extensions
+ * @since 1.0.0
+ */
+
+namespace Activitypub_Event_Extensions\Admin;
+
+/**
+ * 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 array
+	 */
+	protected $event_plugin;
+
+	/**
+	 * Adds admin notices to an active supported event plugin.
+	 *
+	 * @param array $event_plugin Information about the 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() {
+		return ! in_array( $this->event_plugin['post_type'], get_option( 'activitypub_support_post_types', array() ), true );
+	}
+
+	/**
+	 * Display the admin notices for the plugins.
+	 */
+	public function admin_notice_activitypub_not_enabled_for_post_type() {
+		// 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 && $this->event_plugin['post_type'] === $screen->post_type;
+		$is_event_plugins_settings_page = $this->event_plugin['settings_page_id'] === $screen->id;
+
+		if ( $is_event_plugins_edit_page || $is_event_plugins_settings_page ) {
+			$this->do_admin_notice_post_type_not_activitypub_enabled( $this->event_plugin['plugin_file'] );
+		}
+	}
+
+	/**
+	 * Print admin notice that the current post type is not enabled in the ActivityPub plugin.
+	 *
+	 * @param string $event_plugin_file The event plugin file path.
+	 */
+	private function do_admin_notice_post_type_not_activitypub_enabled( $event_plugin_file ) {
+		$event_plugin_data       = get_plugin_data( WP_PLUGIN_DIR . '/' . $event_plugin_file );
+		$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',
+				'activitypub-event-extensions'
+			),
+			esc_html( $activitypub_plugin_data['Name'] ),
+			esc_html( $event_plugin_data['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 +1,100 @@
+<?php
+/**
+ * Class responsible for general admin notices.
+ *
+ * Notices for guiding to proper configuration of this plugin.
+ *
+ * @package Activitypub_Event_Extensions
+ * @since 1.0.0
+ */
+
+namespace Activitypub_Event_Extensions\Admin;
+
+/**
+ * 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 ACTIVITYPUB_EVENT_EXTENSIONS_SUPPORTED_EVENT_PLUGINS_URL = 'https://code.event-federation.eu/Event-Federation/wordpress-activitypub-event-extensions#events-plugin-that-will-be-supported-at-first';
+
+	/**
+	 * Allowed HTML for admin notices.
+	 *
+	 * @var array
+	 */
+	const ALLOWED_HTML = array(
+		'a' => array(
+			'href'  => true,
+			'title' => 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: the name of the event plugin a admin notice is shown. 2: The name of the ActivityPub plugin. */
+			_x(
+				'For the ActivityPub Event Extensions to work, you will need to install and activate the <a href="%1$s">ActivityPub</a> plugin.',
+				'admin notice',
+				'activitypub-event-extensions'
+			),
+			esc_html( self::ACTIVITYPUB_PLUGIN_URL ),
+			admin_url( 'options-general.php?page=activitypub&tab=settings' )
+		);
+	}
+
+	/**
+	 * Warning that no supported event plugin can be found.
+	 *
+	 * @return string
+	 */
+	public static function get_admin_notice_no_supported_event_plugin_active(): string {
+		return sprintf(
+			/* translators: 1: the name of the event plugin a admin notice is shown. 2: The name of the ActivityPub plugin. */
+			_x(
+				'The Plugin <i>ActivityPub Event Extensions</i> is of no use, because you do not have installed and activated a supported Event Plugin.
+				<br> For a list of supported Event Plugins see  <a href="%1$s">here</a>.',
+				'admin notice',
+				'activitypub-event-extensions'
+			),
+			esc_html( self::ACTIVITYPUB_EVENT_EXTENSIONS_SUPPORTED_EVENT_PLUGINS_URL ),
+			admin_url( 'options-general.php?page=activitypub&tab=settings' )
+		);
+	}
+
+	/**
+	 * Warning if the plugin is Active and the ActivityPub plugin is not.
+	 *
+	 * @return void
+	 */
+	public static function activitypub_plugin_not_enabled() {
+		$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 when no supported Even Plugin is installed and active.
+	 *
+	 * @return void
+	 */
+	public static function no_supported_event_plugin_active() {
+		$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/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 +1,66 @@
+<?php
+/**
+ * Class responsible for autoloading ActivityPub Event Extensions 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 Activitypub_Event_Extensions
+ * @since 1.0.0
+ */
+
+namespace Activitypub_Event_Extensions;
+
+// 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 = ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_DIR . '/includes/';
+				$base     = 'Activitypub_Event_Extensions\\';
+
+				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-setup.php

@@ -0,0 +1,232 @@
+<?php
+/**
+ * Class responsible for initializing ActivityPub Event Extensions.
+ *
+ * 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 Activitypub_Event_Extensions
+ * @since 1.0.0
+ */
+
+namespace Activitypub_Event_Extensions;
+
+use Activitypub_Event_Extensions\Admin\Event_Plugin_Admin_Notices;
+use Activitypub_Event_Extensions\Admin\General_Admin_Notices;
+
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+require_once ABSPATH . 'wp-admin/includes/plugin.php';
+
+/**
+ * Class Setup.
+ *
+ * This class is responsible for initializing ActivityPub Event Extensions.
+ *
+ * @since 1.0.0
+ */
+class Setup {
+	const SUPPORTED_EVENT_PLUGINS = array(
+		'events_manager'      => array(
+			'plugin_file'       => 'events-manager/events-manager.php',
+			'post_type'         => 'event',
+			'settings_page'     => 'options-general.php?page=vsel',
+			'transformer_class' => 'Events_Manager',
+		),
+		'gatherpress'         => array(
+			'plugin_file'       => 'gatherpress/gatherpress.php',
+			'post_type'         => 'gatherpress_event',
+			'transformer_class' => 'GatherPress',
+			'settings_page_id'  => 'gatherpress_general',
+		),
+		'the_events_calendar' => array(
+			'plugin_file'       => 'the-events-calendar/the-events-calendar.php',
+			'post_type'         => 'tribe_events',
+			'transformer_class' => 'Tribe',
+			'settings_page_id'  => 'tribe_general',
+		),
+		'vsel'                => array(
+			'plugin_file'       => 'very-simple-event-list/vsel.php',
+			'post_type'         => 'event',
+			'settings_page_id'  => 'settings_page_vsel',
+			'transformer_class' => 'VS_Event',
+		),
+	);
+
+	/**
+	 * Keep the information whether the ActivityPub plugin is active.
+	 *
+	 * @var boolean
+	 */
+	protected $activitypub_plugin_is_active = false;
+
+	/**
+	 * Holds an array of the currently activated supported event plugins.
+	 *
+	 * @var array
+	 */
+	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 = is_plugin_active( 'activitypub/activitypub.php' );
+		$this->active_event_plugins         = self::detect_supported_event_plugins();
+		$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;
+	}
+
+	/**
+	 * Function that checks for supported activated event plugins.
+	 *
+	 * @return array List of supported event plugins as keys from the SUPPORTED_EVENT_PLUGINS const.
+	 */
+	public static function detect_supported_event_plugins(): array {
+		$active_event_plugins = array();
+		foreach ( self::SUPPORTED_EVENT_PLUGINS as $event_plugin_key => $event_plugin ) {
+			if ( \is_plugin_active( $event_plugin['plugin_file'] ) ) {
+				$active_event_plugins[ $event_plugin_key ] = $event_plugin;
+			}
+		}
+		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
+	 */
+	protected function setup_hooks(): void {
+		register_activation_hook( ACTIVITYPUB_EVENT_EXTENSIONS_PLUGIN_FILE, array( $this, 'activate' ) );
+
+		add_action( 'admin_init', array( $this, 'do_admin_notices' ) );
+
+		// 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_filter( 'activitypub_transformer', array( $this, 'register_activitypub_event_transformer' ), 10, 3 );
+	}
+
+	/**
+	 * 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( 'Activitypub_Event_Extensions\Admin\General_Admin_Notices', 'activitypub_plugin_not_enabled' ), 10, 1 );
+		}
+		if ( empty( $this->active_event_plugins ) ) {
+			// No supported Event Plugin is active.
+			add_action( 'admin_notices', array( 'Activitypub_Event_Extensions\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|null {
+		// 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['post_type'] ) {
+				$transformer_class = 'Activitypub_Event_Extensions\Activitypub\Transformer\\' . $event_plugin['transformer_class'];
+				return new $transformer_class( $wp_object );
+			}
+		}
+
+		// Return the default transformer.
+		return $transformer;
+	}
+
+	/**
+	 * Activates the ActivityPub Event Extensions plugin.
+	 *
+	 * This method handles the activation of the ActivityPub Event Extensions plugin.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	public function activate() {
+		// Don't allow plugin activation, when the ActivityPub plugin is not activated yet.
+		if ( ! $this->activitypub_plugin_is_active ) {
+			deactivate_plugins( plugin_basename( ACTIVITYPUB_EVENT_EXTENSIONS_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( ACTIVITYPUB_EVENT_EXTENSIONS_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 ),
+			);
+		}
+		// 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['post_type'], $activitypub_supported_post_types, true ) ) {
+				$activitypub_supported_post_types[] = $event_plugin['post_type'];
+			}
+		}
+		update_option( 'activitypub_support_post_types', $activitypub_supported_post_types );
+	}
+}