store permalink in post meta for trashed posts

this should quick fix #16 without changing the permalink structure

includes/class-activitypub.php

@@ -24,6 +24,8 @@ class Activitypub {
 		}
 
 		\add_action( 'transition_post_status', array( '\Activitypub\Activitypub', 'schedule_post_activity' ), 10, 3 );
+		\add_action( 'wp_trash_post', array( '\Activitypub\Activitypub', 'trash_post' ), 10 );
+		\add_action( 'untrash_post', array( '\Activitypub\Activitypub', 'untrash_post' ), 10 );
 	}
 
 	/**
@@ -185,4 +187,26 @@ class Activitypub {
 		}
 		return \get_comment_meta( $comment->comment_ID, 'avatar_url', true );
 	}
+
+	/**
+	 * Store permalink in meta, to send delete Activity
+	 *
+	 * @param string $post_id The Post ID
+	 *
+	 * @return void
+	 */
+	public static function trash_post( $post_id ) {
+		\add_post_meta( $post_id, 'activitypub_canonical_url', \get_permalink( $post_id ) );
+	}
+
+	/**
+	 * Delete permalink from meta
+	 *
+	 * @param string $post_id The Post ID
+	 *
+	 * @return void
+	 */
+	public static function untrash_post( $post_id ) {
+		\delete_post_meta( $post_id, 'activitypub_canonical_url' );
+	}
 }

includes/model/class-post.php

@@ -69,10 +69,15 @@ class Post {
 
 	public function generate_id() {
 		$post = $this->post;
+
+		if ( 'trash' === get_post_status( $post ) ) {
+			$permalink = \get_post_meta( $post, 'activitypub_canonical_url', true );
+		} else {
 			$permalink = \get_permalink( $post );
+		}
 
 		// replace 'trashed' for delete activity
-		return \str_replace( '__trashed', '', $permalink );
+		return $permalink;
 	}
 
 	public function generate_attachments() {