wpse playlist shortcode - single file with PHP 5.2.x support

<?php 
/**
 * Plugin Name: WPSE Playlist shortcode for external files - a single file with PHP 5.2.x support
 * Description: This plugin allows you to use external audio or video files with the native WordPress playlist, through the use of the [wpse_playlist] and [wpse_trac] shortcodes.
 * Plugin URI:  https://gist.github.com/birgire/fbd961bc682276830a0d/
 * Author:      birgire
 * Author URI:  https://github.com/birgire
 * Version:     0.0.5b
 */

/**
 * Check out the main project page here (PHP 5.3+ support):
 *
 * https://github.com/birgire/wpse-playlist
 *
 */


/**
 * Register shortcodes:
 */

add_action( 'wp', 'wpse_playlist_init' );

function wpse_playlist_init()
{
    if( class_exists( 'WPSE_Playlist' ) )
    {
        $playlist = new WPSE_Playlist;
        $playlist->init();
    }
}



/**
 * Class: WPSE_Playlist
 */

class WPSE_Playlist
{
    protected $type     = '';
    protected $types    = array( 'audio', 'video' );
    protected $instance = 0;
    
    /**
     * Init - Register shortcodes
     */

    public function init()
    {
        add_shortcode( 'wpse_playlist', array( $this, 'playlist_shortcode' ) );
        add_shortcode( 'wpse_trac',     array( $this, 'trac_shortcode'     ) );
    }


    /**
     * Callback for the [wpse_playlist] shortcode
     */

    public function playlist_shortcode( $atts = array(), $content = '' ) 
    {        
        $this->instance++;
        $atts = shortcode_atts( 
            array(
                'type'          => 'audio',
                'style'         => 'light',
                'tracklist'     => 'true',
                'tracknumbers'  => 'true',
                'images'        => 'true',
                'artists'       => 'true',
                'current'       => 'true',
				'loop'          => 'false',
				'autoplay'      => 'false',
				'id'            => '',
				'width'         => '',
				'height'        => '',
            ), $atts, 'wpse_playlist_shortcode' );

        //----------
        // Input
        //----------
        $atts['id']           = esc_attr( $atts['id'] );
        $atts['type']         = esc_attr( $atts['type'] );
        $atts['style']        = esc_attr( $atts['style'] );
        $atts['tracklist']    = filter_var( $atts['tracklist'], FILTER_VALIDATE_BOOLEAN );
        $atts['tracknumbers'] = filter_var( $atts['tracknumbers'], FILTER_VALIDATE_BOOLEAN );
        $atts['images']       = filter_var( $atts['images'], FILTER_VALIDATE_BOOLEAN );
        $atts['autoplay']     = filter_var( $atts['current'], FILTER_VALIDATE_BOOLEAN );

        // Audio specific:
        $atts['artists']      = filter_var( $atts['artists'], FILTER_VALIDATE_BOOLEAN );
        $atts['current']      = filter_var( $atts['current'], FILTER_VALIDATE_BOOLEAN );

        // Video specific:
        $atts['loop']         = filter_var( $atts['loop'], FILTER_VALIDATE_BOOLEAN );

        // Nested shortcode support:
        $this->type           = ( in_array( $atts['type'], $this->types, TRUE ) ) ? $atts['type'] : 'audio';
 
        // Get tracs:
        $content              = strip_tags( nl2br( do_shortcode( $content ) ) );

        // Replace last comma:
        if( FALSE !== ( $pos = strrpos( $content, ',' ) ) )
        {
            $content = substr_replace( $content, '', $pos, 1 );
        }

        // Enqueue default scripts and styles for the playlist.
        ( 1 === $this->instance ) && do_action( 'wp_playlist_scripts', $atts['type'], $atts['style'] );

        //----------
        // Output
        //----------
        $html = '';
        $html .= sprintf( '<div class="wp-playlist wp-%s-playlist wp-playlist-%s">', 
            $this->type, 
            $atts['style'] 
        );

        // Current audio item:
        if( $atts['current'] && 'audio' === $this->type )
        {
            $html .= '<div class="wp-playlist-current-item"></div>';   
        }
        
        // Video player:					  
        if( 'video' === $this->type ):
            $html .= sprintf( '<video controls="controls" preload="none" width="%s" height="%s"></video>',
                $atts['style'],
                $atts['width'],
                $atts['height']
            );
        // Audio player:					  
        else:
            $html .= sprintf( '<audio controls="controls" preload="metadata"></audio>', 
			    $atts['style'] 
            );
        endif;

        // Next/Previous:
        $html .= '<div class="wp-playlist-next"></div><div class="wp-playlist-prev"></div>';

        // JSON	
        $html .= sprintf( '
            <script class="wp-playlist-script" type="application/json">{
                "type":"%s",
                "tracklist":%b,
                "tracknumbers":%b,
                "images":%b,
                "artists":%b,
                "tracks":[%s]
            }</script></div>', 
            $atts['type'], 
            $atts['tracklist'], 
            $atts['tracknumbers'],  
            $atts['images'],
            $atts['artists'],
            $content
        );

        return $html;
    }

    /**
     * Callback for the [wpse_trac] shortcode
     */

     public function trac_shortcode( $atts = array(), $content = '' ) 
    {        
        $atts = shortcode_atts( 
            array(
            'src'                   => '',
            'type'                  => ( 'video' === $this->type ) ? 'video/mp4' : 'audio/mpeg',
            'title'                 => '',
            'caption'               => '',
            'description'           => '',
            'image_src'             => sprintf( '%s/wp-includes/images/media/%s.png', get_site_url(), $this->type ),
            'image_width'           => '48',
            'image_height'          => '64',
            'thumb_src'             => sprintf( '%s/wp-includes/images/media/%s.png', get_site_url(), $this->type ),
            'thumb_width'           => '48',
            'thumb_height'          => '64',
            'meta_artist'           => '',
            'meta_album'            => '',
            'meta_genre'            => '',
            'meta_length_formatted' => '',
            'dimensions_original_width'  => '300',
            'dimensions_original_height' => '200',
            'dimensions_resized_width'   => '600',
            'dimensions_resized_height'  => '400',
        ), $atts, 'wpse_trac_shortcode' );

        //----------
        // Input
        //----------
        $data['src']                      = esc_url( $atts['src'] );
        $data['title']                    = sanitize_text_field( $atts['title'] );
        $data['type']                     = sanitize_text_field( $atts['type'] );
        $data['caption']                  = sanitize_text_field( $atts['caption'] );
        $data['description']              = sanitize_text_field( $atts['description'] );
        $data['image']['src']             = esc_url( $atts['image_src'] );
        $data['image']['width']           = intval( $atts['image_width'] );
        $data['image']['height']          = intval( $atts['image_height'] );
        $data['thumb']['src']             = esc_url( $atts['thumb_src'] );
        $data['thumb']['width']           = intval( $atts['thumb_width'] );
        $data['thumb']['height']          = intval( $atts['thumb_height'] );
        $data['meta']['length_formatted'] = sanitize_text_field( $atts['meta_length_formatted'] );

        // Video related:
        if( 'video' === $this->type ) 
        {
            $data['dimensions']['original']['width']  = sanitize_text_field( $atts['dimensions_original_width'] );
            $data['dimensions']['original']['height'] = sanitize_text_field( $atts['dimensions_original_height'] );
            $data['dimensions']['resized']['width']   = sanitize_text_field( $atts['dimensions_resized_width'] );
            $data['dimensions']['resized']['height']  = sanitize_text_field( $atts['dimensions_resized_height'] );

       // Audio related:
        } else {
            $data['meta']['artist']           = sanitize_text_field( $atts['meta_artist'] );
            $data['meta']['album']            = sanitize_text_field( $atts['meta_album'] );
            $data['meta']['genre']            = sanitize_text_field( $atts['meta_genre'] );
        }

        //----------
        // Output:           
        //----------
        return json_encode( $data ) . ',';      
    }

} // end class