Add Mastodon Apps status provider (#978)

---------

Co-authored-by: Matthias Pfefferle <[email protected]>

integration/class-enable-mastodon-apps.php

@@ -13,6 +13,7 @@
 use Activitypub\Collection\Actors;
 use Activitypub\Collection\Followers;
 use Activitypub\Collection\Extra_Fields;
+use Activitypub\Transformer\Factory;
 use Enable_Mastodon_Apps\Mastodon_API;
 use Enable_Mastodon_Apps\Entity\Account;
 use Enable_Mastodon_Apps\Entity\Status;
@@ -36,6 +37,7 @@ public static function init() {
 		\add_filter( 'mastodon_api_account_followers', array( self::class, 'api_account_followers' ), 10, 2 );
 		\add_filter( 'mastodon_api_account', array( self::class, 'api_account_external' ), 15, 2 );
 		\add_filter( 'mastodon_api_account', array( self::class, 'api_account_internal' ), 9, 2 );
+		\add_filter( 'mastodon_api_status', array( self::class, 'api_status' ), 9, 2 );
 		\add_filter( 'mastodon_api_search', array( self::class, 'api_search' ), 40, 2 );
 		\add_filter( 'mastodon_api_search', array( self::class, 'api_search_by_url' ), 40, 2 );
 		\add_filter( 'mastodon_api_get_posts_query_args', array( self::class, 'api_get_posts_query_args' ) );
@@ -324,6 +326,150 @@ function ( $field ) {
 		return $account;
 	}
 
+	/**
+	 * Use our representation of posts to power each status item.
+	 * Includes proper referncing of 3rd party comments that arrived via federation.
+	 *
+	 * @param null|Status $status The status, typically null to allow later filters their shot.
+	 * @param int         $post_id The post ID.
+	 * @return Status|null The status.
+	 */
+	public static function api_status( $status, $post_id ) {
+		$post = \get_post( $post_id );
+		if ( ! $post ) {
+			return $status;
+		}
+
+		// EMA makes a `comment` post_type to mirror comments and so that there can be a single get_posts() call for everything.
+		if ( get_post_type( $post ) === 'comment' ) {
+			$comment_id = get_post_meta( $post->ID, 'comment_id', true );
+			if ( $comment_id ) {
+				return self::api_comment_status( $comment_id, $post_id );
+			}
+		}
+
+		return self::api_post_status( $post_id );
+	}
+
+	/**
+	 * Transforms a WordPress post into a Mastodon-compatible status object.
+	 *
+	 * Takes a post ID, transforms it into an ActivityPub object, and converts
+	 * it to a Mastodon API status format including the author's account info.
+	 *
+	 * @param int $post_id The WordPress post ID to transform.
+	 * @return Status|null The Mastodon API status object, or null if the post is not found
+	 */
+	private static function api_post_status( $post_id ) {
+		$post    = Factory::get_transformer( get_post( $post_id ) );
+		$data    = $post->to_object()->to_array();
+		$account = self::api_account_internal( null, get_post_field( 'post_author', $post_id ) );
+		return self::activity_to_status( $data, $account, $post_id );
+	}
+
+	/**
+	 * Traditional WP commenters may leave a URL, which itself may be a valid actor.
+	 * If so, we'll use that actor's data to represent the comment.
+	 *
+	 * @param string $url The URL.
+	 * @return Account|false The account or false.
+	 */
+	private static function maybe_get_account_for_actor( $url ) {
+		if ( empty( $url ) ) {
+			return false;
+		}
+		$uri = Webfinger_Util::resolve( $url );
+		if ( $uri && ! is_wp_error( $uri ) ) {
+			return self::get_account_for_actor( $uri );
+		}
+		// Next, if the URL does not have a path, we'll try to resolve it in the form of [email protected].
+		$parts = \wp_parse_url( $url );
+		if ( ( ! isset( $parts['path'] ) || ! $parts['path'] ) && isset( $parts['host'] ) ) {
+			$url  = trailingslashit( $url ) . '@' . $parts['host'];
+			$acct = Webfinger_Util::uri_to_acct( $url );
+			if ( $acct && ! is_wp_error( $acct ) ) {
+				return self::get_account_for_actor( $acct );
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Convert an local WP comment into a pseudo-account, after first checking if their
+	 * supplied URL is a valid actor.
+	 *
+	 * @param \WP_Comment $comment The comment.
+	 * @return Account The account.
+	 */
+	private static function get_account_for_local_comment( $comment ) {
+		$maybe_actor = self::maybe_get_account_for_actor( $comment->comment_author_url );
+		if ( $maybe_actor ) {
+			return $maybe_actor;
+		}
+
+		// We will make a pretend local account for this comment.
+		$account                 = new Account();
+		$account->id             = 999999; // This is a fake ID.
+		$account->username       = $comment->comment_author;
+		$account->acct           = sprintf( 'comments@%s', wp_parse_url( home_url(), PHP_URL_HOST ) );
+		$account->display_name   = $comment->comment_author;
+		$account->url            = get_comment_link( $comment );
+		$account->avatar         = get_avatar_url( $comment->comment_author_email );
+		$account->avatar_static  = $account->avatar;
+		$account->created_at     = new DateTime( $comment->comment_date_gmt );
+		$account->last_status_at = new DateTime( $comment->comment_date_gmt );
+		$account->note           = sprintf(
+			/* translators: %s: comment author name */
+			__( 'This is a local comment by %s, not a fediverse comment. This profile cannot be followed.', 'activitypub' ),
+			$comment->comment_author
+		);
+
+		return $account;
+	}
+
+	/**
+	 * Convert a WordPress comment to a Status.
+	 *
+	 * @param int $comment_id The comment ID.
+	 * @param int $post_id    The post ID (this is the mirrored `comment` post).
+	 *
+	 * @return Status|null The status.
+	 */
+	private static function api_comment_status( $comment_id, $post_id ) {
+		$comment = get_comment( $comment_id );
+		$post    = get_post( $post_id );
+		if ( ! $comment || ! $post ) {
+			return null;
+		}
+
+		$is_remote_comment = get_comment_meta( $comment->comment_ID, 'protocol', true ) === 'activitypub';
+
+		if ( $is_remote_comment ) {
+			$account = self::get_account_for_actor( $comment->comment_author_url );
+			// @todo fallback to locally stored data from the time the comment was made,
+			// if the remote actor is not found/no longer available.
+		} else {
+			$account = self::get_account_for_local_comment( $comment );
+		}
+
+		if ( ! $account ) {
+			return null;
+		}
+
+		$status                 = new Status();
+		$status->id             = $comment->comment_ID;
+		$status->created_at     = new DateTime( $comment->comment_date_gmt );
+		$status->content        = $comment->comment_content;
+		$status->account        = $account;
+		$status->visibility     = 'public';
+		$status->uri            = get_comment_link( $comment );
+		$status->in_reply_to_id = $post->post_parent;
+
+		return $status;
+	}
+
+
 	/**
 	 * Get account for actor.
 	 *
@@ -332,7 +478,7 @@ function ( $field ) {
 	 * @return Account|null The account.
 	 */
 	private static function get_account_for_actor( $uri ) {
-		if ( ! is_string( $uri ) ) {
+		if ( ! is_string( $uri ) || empty( $uri ) ) {
 			return null;
 		}
 		$data = get_remote_metadata_by_actor( $uri );
@@ -343,6 +489,10 @@ private static function get_account_for_actor( $uri ) {
 		$account = new Account();
 
 		$acct = Webfinger_Util::uri_to_acct( $uri );
+		if ( ! $acct || is_wp_error( $acct ) ) {
+			return null;
+		}
+
 		if ( str_starts_with( $acct, 'acct:' ) ) {
 			$acct = substr( $acct, 5 );
 		}
@@ -489,10 +639,11 @@ public static function api_get_posts_query_args( $args ) {
 	 *
 	 * @param array   $item    The activity.
 	 * @param Account $account The account.
+	 * @param int     $post_id The post ID. Optional, but will be preferred in the Status.
 	 *
 	 * @return Status|null The status.
 	 */
-	private static function activity_to_status( $item, $account ) {
+	private static function activity_to_status( $item, $account, $post_id = null ) {
 		if ( isset( $item['object'] ) ) {
 			$object = $item['object'];
 		} else {
@@ -504,7 +655,7 @@ private static function activity_to_status( $item, $account ) {
 		}
 
 		$status             = new Status();
-		$status->id         = $object['id'];
+		$status->id         = $post_id ?? $object['id'];
 		$status->created_at = new DateTime( $object['published'] );
 		$status->content    = $object['content'];
 		$status->account    = $account;