wp-fedistream/includes/ActivityPub/AlbumTransformer.php

<?php
/**
 * Album Transformer for ActivityPub.
 *
 * @package WP_FediStream
 */

namespace WP_FediStream\ActivityPub;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Transforms Album posts to ActivityPub Collection objects.
 */
class AlbumTransformer {

	/**
	 * The album post.
	 *
	 * @var \WP_Post
	 */
	protected \WP_Post $post;

	/**
	 * Constructor.
	 *
	 * @param \WP_Post $post The album post.
	 */
	public function __construct( \WP_Post $post ) {
		$this->post = $post;
	}

	/**
	 * Get the ActivityPub object type.
	 *
	 * @return string
	 */
	public function get_type(): string {
		return 'Collection';
	}

	/**
	 * Get the object ID (URI).
	 *
	 * @return string
	 */
	public function get_id(): string {
		return get_permalink( $this->post->ID );
	}

	/**
	 * Get the object name (title).
	 *
	 * @return string
	 */
	public function get_name(): string {
		$album_type = get_post_meta( $this->post->ID, '_fedistream_album_type', true );
		$type_label = '';

		switch ( $album_type ) {
			case 'ep':
				$type_label = ' (EP)';
				break;
			case 'single':
				$type_label = ' (Single)';
				break;
			case 'compilation':
				$type_label = ' (Compilation)';
				break;
		}

		return $this->post->post_title . $type_label;
	}

	/**
	 * Get the content (liner notes/description).
	 *
	 * @return string
	 */
	public function get_content(): string {
		$content = $this->post->post_content;

		// Apply content filters for proper formatting.
		$content = apply_filters( 'the_content', $content );

		return wp_kses_post( $content );
	}

	/**
	 * Get the summary (excerpt).
	 *
	 * @return string
	 */
	public function get_summary(): string {
		if ( ! empty( $this->post->post_excerpt ) ) {
			return wp_strip_all_tags( $this->post->post_excerpt );
		}

		// Build summary from album info.
		$artist_id = get_post_meta( $this->post->ID, '_fedistream_album_artist', true );
		$artist    = $artist_id ? get_post( $artist_id ) : null;

		$release_date = get_post_meta( $this->post->ID, '_fedistream_release_date', true );
		$track_count  = (int) get_post_meta( $this->post->ID, '_fedistream_total_tracks', true );

		$summary = '';
		if ( $artist ) {
			$summary .= sprintf( __( 'By %s', 'wp-fedistream' ), $artist->post_title );
		}
		if ( $release_date ) {
			/* translators: %s: release date */
			$summary .= ' ' . sprintf( __( '- Released %s', 'wp-fedistream' ), $release_date );
		}
		if ( $track_count ) {
			/* translators: %d: number of tracks */
			$summary .= ' ' . sprintf( _n( '- %d track', '- %d tracks', $track_count, 'wp-fedistream' ), $track_count );
		}

		return trim( $summary );
	}

	/**
	 * Get the URL (permalink).
	 *
	 * @return string
	 */
	public function get_url(): string {
		return get_permalink( $this->post->ID );
	}

	/**
	 * Get the attributed actor.
	 *
	 * @return string Artist URI.
	 */
	public function get_attributed_to(): string {
		$artist_id = get_post_meta( $this->post->ID, '_fedistream_album_artist', true );

		if ( ! $artist_id ) {
			return '';
		}

		return get_permalink( $artist_id );
	}

	/**
	 * Get the published date.
	 *
	 * @return string ISO 8601 date.
	 */
	public function get_published(): string {
		// Use release date if available, otherwise post date.
		$release_date = get_post_meta( $this->post->ID, '_fedistream_release_date', true );

		if ( $release_date ) {
			$date = \DateTime::createFromFormat( 'Y-m-d', $release_date );
			if ( $date ) {
				return $date->format( 'c' );
			}
		}

		return get_the_date( 'c', $this->post );
	}

	/**
	 * Get the updated date.
	 *
	 * @return string ISO 8601 date.
	 */
	public function get_updated(): string {
		return get_the_modified_date( 'c', $this->post );
	}

	/**
	 * Get the total duration.
	 *
	 * @return string ISO 8601 duration.
	 */
	public function get_duration(): string {
		$seconds = (int) get_post_meta( $this->post->ID, '_fedistream_total_duration', true );

		if ( ! $seconds ) {
			// Calculate from tracks.
			$tracks = $this->get_tracks();
			foreach ( $tracks as $track ) {
				$seconds += (int) get_post_meta( $track->ID, '_fedistream_duration', true );
			}
		}

		if ( ! $seconds ) {
			return '';
		}

		return $this->format_duration_iso8601( $seconds );
	}

	/**
	 * Get the tracks in this album.
	 *
	 * @return array Array of WP_Post objects.
	 */
	public function get_tracks(): array {
		$args = array(
			'post_type'      => 'fedistream_track',
			'post_status'    => 'publish',
			'posts_per_page' => -1,
			'meta_key'       => '_fedistream_track_number', // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
			'orderby'        => 'meta_value_num',
			'order'          => 'ASC',
			'meta_query'     => array( // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
				array(
					'key'   => '_fedistream_album_id',
					'value' => $this->post->ID,
				),
			),
		);

		$query = new \WP_Query( $args );

		return $query->posts;
	}

	/**
	 * Get the total item count.
	 *
	 * @return int
	 */
	public function get_total_items(): int {
		$count = (int) get_post_meta( $this->post->ID, '_fedistream_total_tracks', true );

		if ( ! $count ) {
			$count = count( $this->get_tracks() );
		}

		return $count;
	}

	/**
	 * Get the collection items (track URIs).
	 *
	 * @return array
	 */
	public function get_items(): array {
		$tracks = $this->get_tracks();
		$items  = array();

		foreach ( $tracks as $track ) {
			$transformer = new TrackTransformer( $track );
			$items[]     = $transformer->to_object();
		}

		return $items;
	}

	/**
	 * Get the image/artwork attachment.
	 *
	 * @return array|null
	 */
	public function get_image_attachment(): ?array {
		$thumbnail_id = get_post_thumbnail_id( $this->post->ID );

		if ( ! $thumbnail_id ) {
			return null;
		}

		$image = wp_get_attachment_image_src( $thumbnail_id, 'medium' );
		if ( ! $image ) {
			return null;
		}

		return array(
			'type'      => 'Image',
			'mediaType' => get_post_mime_type( $thumbnail_id ),
			'url'       => $image[0],
			'width'     => $image[1],
			'height'    => $image[2],
		);
	}

	/**
	 * Get tags (genres).
	 *
	 * @return array
	 */
	public function get_tags(): array {
		$tags = array();

		// Get genres.
		$genres = get_the_terms( $this->post->ID, 'fedistream_genre' );
		if ( $genres && ! is_wp_error( $genres ) ) {
			foreach ( $genres as $genre ) {
				$tags[] = array(
					'type' => 'Hashtag',
					'name' => '#' . sanitize_title( $genre->name ),
					'href' => get_term_link( $genre ),
				);
			}
		}

		return $tags;
	}

	/**
	 * Transform to ActivityPub object array.
	 *
	 * @return array
	 */
	public function to_object(): array {
		$object = array(
			'@context'     => 'https://www.w3.org/ns/activitystreams',
			'type'         => $this->get_type(),
			'id'           => $this->get_id(),
			'name'         => $this->get_name(),
			'summary'      => $this->get_summary(),
			'content'      => $this->get_content(),
			'url'          => $this->get_url(),
			'attributedTo' => $this->get_attributed_to(),
			'published'    => $this->get_published(),
			'updated'      => $this->get_updated(),
			'totalItems'   => $this->get_total_items(),
			'items'        => $this->get_items(),
		);

		// Add duration.
		$duration = $this->get_duration();
		if ( $duration ) {
			$object['duration'] = $duration;
		}

		// Add image.
		$image = $this->get_image_attachment();
		if ( $image ) {
			$object['image'] = $image;
		}

		// Add tags.
		$tags = $this->get_tags();
		if ( ! empty( $tags ) ) {
			$object['tag'] = $tags;
		}

		// Add album-specific metadata.
		$album_type = get_post_meta( $this->post->ID, '_fedistream_album_type', true );
		if ( $album_type ) {
			$object['albumType'] = $album_type;
		}

		$upc = get_post_meta( $this->post->ID, '_fedistream_upc', true );
		if ( $upc ) {
			$object['upc'] = $upc;
		}

		$catalog = get_post_meta( $this->post->ID, '_fedistream_catalog_number', true );
		if ( $catalog ) {
			$object['catalogNumber'] = $catalog;
		}

		$release_date = get_post_meta( $this->post->ID, '_fedistream_release_date', true );
		if ( $release_date ) {
			$object['releaseDate'] = $release_date;
		}

		return $object;
	}

	/**
	 * Create a Create activity for this album.
	 *
	 * @return array
	 */
	public function to_create_activity(): array {
		$actor = $this->get_attributed_to();

		return array(
			'@context'  => 'https://www.w3.org/ns/activitystreams',
			'type'      => 'Create',
			'id'        => $this->get_id() . '#activity-create',
			'actor'     => $actor,
			'published' => $this->get_published(),
			'to'        => array( 'https://www.w3.org/ns/activitystreams#Public' ),
			'cc'        => array( $actor . '/followers' ),
			'object'    => $this->to_object(),
		);
	}

	/**
	 * Create an Announce activity for this album.
	 *
	 * @param string $actor_uri The actor announcing the album.
	 * @return array
	 */
	public function to_announce_activity( string $actor_uri ): array {
		return array(
			'@context'  => 'https://www.w3.org/ns/activitystreams',
			'type'      => 'Announce',
			'id'        => $this->get_id() . '#activity-announce-' . time(),
			'actor'     => $actor_uri,
			'published' => gmdate( 'c' ),
			'to'        => array( 'https://www.w3.org/ns/activitystreams#Public' ),
			'cc'        => array( $actor_uri . '/followers' ),
			'object'    => $this->get_id(),
		);
	}

	/**
	 * Format duration as ISO 8601.
	 *
	 * @param int $seconds The duration in seconds.
	 * @return string ISO 8601 duration.
	 */
	private function format_duration_iso8601( int $seconds ): string {
		$hours   = floor( $seconds / 3600 );
		$minutes = floor( ( $seconds % 3600 ) / 60 );
		$secs    = $seconds % 60;

		$duration = 'PT';
		if ( $hours > 0 ) {
			$duration .= $hours . 'H';
		}
		if ( $minutes > 0 ) {
			$duration .= $minutes . 'M';
		}
		if ( $secs > 0 || ( $hours === 0 && $minutes === 0 ) ) {
			$duration .= $secs . 'S';
		}

		return $duration;
	}
}