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

namespace WP_FediStream\ActivityPub;

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

/**
 * Transforms Playlist posts to ActivityPub OrderedCollection objects.
 */
class PlaylistTransformer {

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

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

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

	/**
	 * 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 (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 (playlist creator).
	 *
	 * @return string User's ActivityPub actor URI.
	 */
	public function get_attributed_to(): string {
		$user_id = $this->post->post_author;

		// Check if there's an artist associated with this user.
		$artist_args = array(
			'post_type'      => 'fedistream_artist',
			'posts_per_page' => 1,
			'author'         => $user_id,
		);

		$artists = get_posts( $artist_args );

		if ( ! empty( $artists ) ) {
			return get_permalink( $artists[0]->ID );
		}

		// Fall back to user profile URL.
		return get_author_posts_url( $user_id );
	}

	/**
	 * 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 total duration.
	 *
	 * @return string ISO 8601 duration.
	 */
	public function get_duration(): string {
		$seconds = (int) get_post_meta( $this->post->ID, '_fedistream_playlist_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 playlist.
	 *
	 * @return array Array of WP_Post objects.
	 */
	public function get_tracks(): array {
		global $wpdb;

		$table = $wpdb->prefix . 'fedistream_playlist_tracks';

		// Get track IDs in order.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		$track_ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT track_id FROM {$table} WHERE playlist_id = %d ORDER BY position ASC",
				$this->post->ID
			)
		);

		if ( empty( $track_ids ) ) {
			return array();
		}

		// Get track posts in order.
		$args = array(
			'post_type'      => 'fedistream_track',
			'post_status'    => 'publish',
			'post__in'       => $track_ids,
			'orderby'        => 'post__in',
			'posts_per_page' => -1,
		);

		$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_track_count', true );

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

		return $count;
	}

	/**
	 * Get the ordered items (track objects).
	 *
	 * @return array
	 */
	public function get_ordered_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/cover 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 (moods).
	 *
	 * @return array
	 */
	public function get_tags(): array {
		$tags = array();

		// 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;
	}

	/**
	 * Check if the playlist is public.
	 *
	 * @return bool
	 */
	public function is_public(): bool {
		$visibility = get_post_meta( $this->post->ID, '_fedistream_playlist_visibility', true );

		return 'public' === $visibility || empty( $visibility );
	}

	/**
	 * 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(),
			'orderedItems' => $this->get_ordered_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 visibility indicator.
		if ( ! $this->is_public() ) {
			$object['sensitive'] = false;
			$visibility          = get_post_meta( $this->post->ID, '_fedistream_playlist_visibility', true );
			if ( 'unlisted' === $visibility ) {
				$object['visibility'] = 'unlisted';
			}
		}

		// Add collaborative flag.
		$collaborative = get_post_meta( $this->post->ID, '_fedistream_playlist_collaborative', true );
		if ( $collaborative ) {
			$object['collaborative'] = true;
		}

		return $object;
	}

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

		// Determine audience based on visibility.
		$visibility = get_post_meta( $this->post->ID, '_fedistream_playlist_visibility', true );

		$to = array();
		$cc = array();

		if ( 'public' === $visibility || empty( $visibility ) ) {
			$to[] = 'https://www.w3.org/ns/activitystreams#Public';
			$cc[] = $actor . '/followers';
		} elseif ( 'unlisted' === $visibility ) {
			$to[] = $actor . '/followers';
			$cc[] = 'https://www.w3.org/ns/activitystreams#Public';
		} else {
			// Private - only followers.
			$to[] = $actor . '/followers';
		}

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

	/**
	 * Create an Update activity for this playlist.
	 *
	 * @return array
	 */
	public function to_update_activity(): array {
		$actor = $this->get_attributed_to();

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

	/**
	 * 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;
	}
}