Mini Shell

<?php
/**
 * Mixcloud embeds
 *
 * Examples:
 * [mixcloud MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/ /]
 * [mixcloud MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/ width=640 height=480 /]
 * [mixcloud http://www.mixcloud.com/MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/ /]
 * [mixcloud http://www.mixcloud.com/MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/ width=640 height=480 /]
 * [mixcloud]http://www.mixcloud.com/MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/[/mixcloud]
 * [mixcloud]MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/[/mixcloud]
 * [mixcloud http://www.mixcloud.com/mat/playlists/classics/ width=660 height=208 hide_cover=1 hide_tracklist=1]
 *
 * @package automattic/jetpack
 */

/*
 * Register oEmbed provider
 * Example URL: http://app.mixcloud.com/oembed/?url=http://www.mixcloud.com/MalibuRum/play-6-kissy-sellouts-winter-sun-house-party-mix/
 */
wp_oembed_add_provider( '#https?://(?:www\.)?mixcloud\.com/\S*#i', 'https://app.mixcloud.com/oembed/', true );

/**
 * Register mixcloud shortcode.
 *
 * @param array  $atts    Shortcode atttributes.
 * @param string $content Post content.
 */
function mixcloud_shortcode( $atts, $content = null ) {

	if ( empty( $atts[0] ) && empty( $content ) ) {
		return '<!-- mixcloud error: invalid mixcloud resource -->';
	}

	$regular_expression = '/((?<=mixcloud\.com\/)[\w\-\/]+$)|(^[\w\-\/]+$)/i';
	preg_match( $regular_expression, $content, $match );
	if ( ! empty( $match ) ) {
		$resource_id = trim( $match[0] );
	} else {
		preg_match( $regular_expression, $atts[0], $match );
		if ( ! empty( $match ) ) {
			$resource_id = trim( $match[0] );
		}
	}

	if ( empty( $resource_id ) ) {
		return '<!-- mixcloud error: invalid mixcloud resource -->';
	}

	$mixcloud_url = 'https://mixcloud.com/' . $resource_id;

	$atts = shortcode_atts(
		array(
			'width'          => false,
			'height'         => false,
			'color'          => false,
			'light'          => false,
			'dark'           => false,
			'hide_tracklist' => false,
			'hide_cover'     => false,
			'mini'           => false,
			'hide_followers' => false,
			'hide_artwork'   => false,
		),
		$atts
	);

	// remove falsey values.
	$atts = array_filter( $atts );

	$query_args = array( 'url' => $mixcloud_url );
	$query_args = array_merge( $query_args, $atts );

	$url               = add_query_arg( urlencode_deep( $query_args ), 'https://app.mixcloud.com/oembed/' );
	$mixcloud_response = wp_remote_get( $url, array( 'redirection' => 0 ) );
	if ( is_wp_error( $mixcloud_response ) || 200 !== $mixcloud_response['response']['code'] || empty( $mixcloud_response['body'] ) ) {
		return '<!-- mixcloud error: invalid mixcloud resource -->';
	}

	$response_body = json_decode( $mixcloud_response['body'] );

	$html = $response_body->html;

	preg_match( '/sandbox="([^"]*)"/', $html, $matches );

	if ( empty( $matches ) ) { // Mixcloud doesn't use sandbox attribute.
		$html = preg_replace( '/>/', ' sandbox="allow-popups allow-scripts allow-same-origin allow-presentation">', $html, 1 );
	} else { // Mixcloud uses sandbox attribute.

		$allowed_values = array();
		// Here we make sure that these string are not repeated in the sandbox attribute.
		$attrs = array( 'allow-popups', 'allow-scripts', 'allow-same-origin', 'allow-presentation' );
		foreach ( $attrs as $attr ) {
			if ( false === strpos( $matches[1], $attr ) ) {
				$allowed_values[] = $attr;
			}
		}

		$sandbox_value = $matches[1] . ' ' . implode( ' ', $allowed_values );

		$html = preg_replace( '/sandbox="([^"]*)"/', "sandbox=\"$sandbox_value\"", $html );
	}

	return $html;
}
add_shortcode( 'mixcloud', 'mixcloud_shortcode' );