/**
 *
 * Filter subtitles
 *
 * @param array $tracks
 * @param int $post_id
 *
 */
add_filter( 'streamtube/core/post/text_tracks', function( $tracks, $post_id ){

    // Return tracks if they have been manually uploaded through the form.
    // Otherwise, remove these two lines.

    if( $tracks ){
        return $tracks;
    }

    $_tracks = array();

    // Get the video URL meta value
    $video_url = get_post_meta( $post_id, 'video_url', true );

    if( ! $video_url ){
        return false;
    }

    // Extract the YouTube ID from the video URL
    preg_match('/(?:youtube\.com\/(?:[^\/\n\s]+\/\S+\/|(?:v|e(?:mbed)?)\/|.*[?&]v=)|youtu\.be\/)([a-zA-Z0-9_-]{11})/', $video_url, $matches);

    if( ! $matches || ! isset( $matches[1] ) ){
        return false;
    }

    $youtube_id = $matches[1];

    // Directory where subtitle files are stored
    $subtitle_dir = WP_CONTENT_DIR . '/uploads/subtitles/' . $youtube_id;

    // Check if directory exists
    $subtitle_files = array();
    if( is_dir( $subtitle_dir ) ){
        // Scan the directory for .vtt files
        $subtitle_files = glob( $subtitle_dir . '/*.vtt' );
    }

    // Get the text tracks from post meta
    $tracks = get_post_meta( $post_id, 'text_tracks', true );

    if( $tracks && is_array( $tracks ) && array_key_exists( 'languages', $tracks ) && is_array( $tracks['languages'] ) ){
        for ( $i = 0; $i < count( $tracks['languages'] ); $i++) {
            if( $tracks['languages'][$i] && $tracks['sources'][$i] ){
                $file_type = wp_check_filetype( $tracks['sources'][$i] );
                if( array_key_exists( 'ext', $file_type ) && in_array( strtolower( $file_type['ext'] ), apply_filters( 'streamtube/core/text_track_format',  array( 'vtt' ) ) ) ){
                    $_tracks[] = array(
                        'language'  =>  $tracks['languages'][$i],
                        'source'    =>  $tracks['sources'][$i]
                    );
                }
            }
        }
    }

    // Add local subtitle files if not already added
    if( $subtitle_files ){
        foreach ( $subtitle_files as $subtitle_file ) {
            $file_name = basename( $subtitle_file, '.vtt' );
            $file_parts = explode('.', $file_name);

            if( count( $file_parts ) >= 2 && $file_parts[0] === $youtube_id ){
                // Extract language code before the hyphen if present
                $language = explode('-', $file_parts[1])[0];
                $source = content_url( '/uploads/subtitles/' . $youtube_id . '/' . basename( $subtitle_file ) );

                // Check if this language is already added from meta
                $language_exists = false;
                foreach( $_tracks as $track ){
                    if( $track['language'] === $language ){
                        $language_exists = true;
                        break;
                    }
                }

                if( ! $language_exists ){
                    $_tracks[] = array(
                        'language' => $language,
                        'source'   => $source
                    );
                }
            }
        }
    }

    return $_tracks;

}, 10, 2 );