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

namespace WP_FediStream\ActivityPub;

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

/**
 * Transforms Track posts to ActivityPub Audio objects.
 */
class TrackTransformer {

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

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

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

	/**
	 * 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 {
		return $this->post->post_title;
	}

	/**
	 * Get the content (lyrics or 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 );
		}

		// Generate excerpt from content.
		return wp_trim_words( wp_strip_all_tags( $this->post->post_content ), 30 );
	}

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

	/**
	 * Get the attributed actor(s).
	 *
	 * @return array|string Artist(s) URIs.
	 */
	public function get_attributed_to() {
		$artist_ids = get_post_meta( $this->post->ID, '_fedistream_artist_ids', true );

		if ( ! is_array( $artist_ids ) || empty( $artist_ids ) ) {
			// Fall back to album artist.
			$album_id  = get_post_meta( $this->post->ID, '_fedistream_album_id', true );
			$artist_id = $album_id ? get_post_meta( $album_id, '_fedistream_album_artist', true ) : 0;

			if ( $artist_id ) {
				return get_permalink( $artist_id );
			}

			return array();
		}

		// Return single artist or array of artists.
		if ( count( $artist_ids ) === 1 ) {
			return get_permalink( $artist_ids[0] );
		}

		return array_map( 'get_permalink', $artist_ids );
	}

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

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

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

	/**
	 * Get the audio attachment.
	 *
	 * @return array|null
	 */
	public function get_audio_attachment(): ?array {
		$audio_id = get_post_meta( $this->post->ID, '_fedistream_audio_file', true );

		if ( ! $audio_id ) {
			return null;
		}

		$audio_url  = wp_get_attachment_url( $audio_id );
		$mime_type  = get_post_mime_type( $audio_id );
		$audio_meta = wp_get_attachment_metadata( $audio_id );

		if ( ! $audio_url ) {
			return null;
		}

		$attachment = array(
			'type'      => 'Audio',
			'mediaType' => $mime_type ?: 'audio/mpeg',
			'url'       => $audio_url,
			'name'      => $this->post->post_title,
		);

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

		return $attachment;
	}

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

		// Fall back to album artwork.
		if ( ! $thumbnail_id ) {
			$album_id     = get_post_meta( $this->post->ID, '_fedistream_album_id', true );
			$thumbnail_id = $album_id ? get_post_thumbnail_id( $album_id ) : 0;
		}

		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, moods).
	 *
	 * @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 ),
				);
			}
		}

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

		return $tags;
	}

	/**
	 * Get the context (album).
	 *
	 * @return string|null Album URI if available.
	 */
	public function get_context(): ?string {
		$album_id = get_post_meta( $this->post->ID, '_fedistream_album_id', true );

		if ( ! $album_id ) {
			return null;
		}

		return get_permalink( $album_id );
	}

	/**
	 * 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(),
		);

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

		// Add attachments.
		$attachments = array();

		$audio = $this->get_audio_attachment();
		if ( $audio ) {
			$attachments[] = $audio;
		}

		$image = $this->get_image_attachment();
		if ( $image ) {
			$attachments[] = $image;
		}

		if ( ! empty( $attachments ) ) {
			$object['attachment'] = $attachments;
		}

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

		// Add context (album).
		$context = $this->get_context();
		if ( $context ) {
			$object['context'] = $context;
		}

		// Add additional metadata.
		$explicit = get_post_meta( $this->post->ID, '_fedistream_explicit', true );
		if ( $explicit ) {
			$object['sensitive'] = true;
		}

		// Add ISRC if available.
		$isrc = get_post_meta( $this->post->ID, '_fedistream_isrc', true );
		if ( $isrc ) {
			$object['isrc'] = $isrc;
		}

		return $object;
	}

	/**
	 * Create a Create activity for this track.
	 *
	 * @return array
	 */
	public function to_create_activity(): array {
		$attributed_to = $this->get_attributed_to();
		$actor         = is_array( $attributed_to ) ? $attributed_to[0] : $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 track.
	 *
	 * @param string $actor_uri The actor announcing the track.
	 * @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;
	}
}