<?php
/**
 * WordPress API for embedding content.
 *
 * @package WordPress
 * @subpackage oEmbed
 * @since 4.4.0
 */

/**
 * Registers an embed handler.
 *
 * Should probably only be used for sites that do not support oEmbed.
 *
 * @since 2.9.0
 *
 * @global WP_Embed $wp_embed
 *
 * @param string   $id       An internal ID/name for the handler. Needs to be unique.
 * @param string   $regex    The regex that will be used to see if this handler should be used for a URL.
 * @param callable $callback The callback function that will be called if the regex is matched.
 * @param int      $priority Optional. Used to specify the order in which the registered handlers will
 *                           be tested. Default 10.
 */
function wp_embed_register_handler( $id, $regex, $callback, $priority = 10 ) {
	global $wp_embed;
	$wp_embed->register_handler( $id, $regex, $callback, $priority );
}

/**
 * Unregisters a previously-registered embed handler.
 *
 * @since 2.9.0
 *
 * @global WP_Embed $wp_embed
 *
 * @param string $id       The handler ID that should be removed.
 * @param int    $priority Optional. The priority of the handler to be removed. Default 10.
 */
function wp_embed_unregister_handler( $id, $priority = 10 ) {
	global $wp_embed;
	$wp_embed->unregister_handler( $id, $priority );
}

/**
 * Create default array of embed parameters.
 *
 * The width defaults to the content width as specified by the theme. If the
 * theme does not specify a content width, then 500px is used.
 *
 * The default height is 1.5 times the width, or 1000px, whichever is smaller.
 *
 * The 'embed_defaults' filter can be used to adjust either of these values.
 *
 * @since 2.9.0
 *
 * @global int $content_width
 *
 * @param string $url Optional. The URL that should be embedded. Default empty.
 *
 * @return array Default embed parameters.
 */
function wp_embed_defaults( $url = '' ) {
	if ( ! empty( $GLOBALS['content_width'] ) )
		$width = (int) $GLOBALS['content_width'];

	if ( empty( $width ) )
		$width = 500;

	$height = min( ceil( $width * 1.5 ), 1000 );

	/**
	 * Filter the default array of embed dimensions.
	 *
	 * @since 2.9.0
	 *
	 * @param int    $width  Width of the embed in pixels.
	 * @param int    $height Height of the embed in pixels.
	 * @param string $url    The URL that should be embedded.
	 */
	return apply_filters( 'embed_defaults', compact( 'width', 'height' ), $url );
}

/**
 * Attempts to fetch the embed HTML for a provided URL using oEmbed.
 *
 * @since 2.9.0
 *
 * @see WP_oEmbed
 *
 * @param string $url  The URL that should be embedded.
 * @param array  $args Optional. Additional arguments and parameters for retrieving embed HTML.
 *                     Default empty.
 * @return false|string False on failure or the embed HTML on success.
 */
function wp_oembed_get( $url, $args = '' ) {
	require_once( ABSPATH . WPINC . '/class-oembed.php' );
	$oembed = _wp_oembed_get_object();
	return $oembed->get_html( $url, $args );
}

/**
 * Adds a URL format and oEmbed provider URL pair.
 *
 * @since 2.9.0
 *
 * @see WP_oEmbed
 *
 * @param string  $format   The format of URL that this provider can handle. You can use asterisks
 *                          as wildcards.
 * @param string  $provider The URL to the oEmbed provider.
 * @param boolean $regex    Optional. Whether the `$format` parameter is in a RegEx format. Default false.
 */
function wp_oembed_add_provider( $format, $provider, $regex = false ) {
	require_once( ABSPATH . WPINC . '/class-oembed.php' );

	if ( did_action( 'plugins_loaded' ) ) {
		$oembed = _wp_oembed_get_object();
		$oembed->providers[$format] = array( $provider, $regex );
	} else {
		WP_oEmbed::_add_provider_early( $format, $provider, $regex );
	}
}

/**
 * Removes an oEmbed provider.
 *
 * @since 3.5.0
 *
 * @see WP_oEmbed
 *
 * @param string $format The URL format for the oEmbed provider to remove.
 * @return bool Was the provider removed successfully?
 */
function wp_oembed_remove_provider( $format ) {
	require_once( ABSPATH . WPINC . '/class-oembed.php' );

	if ( did_action( 'plugins_loaded' ) ) {
		$oembed = _wp_oembed_get_object();

		if ( isset( $oembed->providers[ $format ] ) ) {
			unset( $oembed->providers[ $format ] );
			return true;
		}
	} else {
		WP_oEmbed::_remove_provider_early( $format );
	}

	return false;
}

/**
 * Determines if default embed handlers should be loaded.
 *
 * Checks to make sure that the embeds library hasn't already been loaded. If
 * it hasn't, then it will load the embeds library.
 *
 * @since 2.9.0
 *
 * @see wp_embed_register_handler()
 */
function wp_maybe_load_embeds() {
	/**
	 * Filter whether to load the default embed handlers.
	 *
	 * Returning a falsey value will prevent loading the default embed handlers.
	 *
	 * @since 2.9.0
	 *
	 * @param bool $maybe_load_embeds Whether to load the embeds library. Default true.
	 */
	if ( ! apply_filters( 'load_default_embeds', true ) ) {
		return;
	}

	wp_embed_register_handler( 'youtube_embed_url', '#https?://(www.)?youtube\.com/(?:v|embed)/([^/]+)#i', 'wp_embed_handler_youtube' );

	wp_embed_register_handler( 'googlevideo', '#http://video\.google\.([A-Za-z.]{2,5})/videoplay\?docid=([\d-]+)(.*?)#i', 'wp_embed_handler_googlevideo' );

	/**
	 * Filter the audio embed handler callback.
	 *
	 * @since 3.6.0
	 *
	 * @param callable $handler Audio embed handler callback function.
	 */
	wp_embed_register_handler( 'audio', '#^https?://.+?\.(' . join( '|', wp_get_audio_extensions() ) . ')$#i', apply_filters( 'wp_audio_embed_handler', 'wp_embed_handler_audio' ), 9999 );

	/**
	 * Filter the video embed handler callback.
	 *
	 * @since 3.6.0
	 *
	 * @param callable $handler Video embed handler callback function.
	 */
	wp_embed_register_handler( 'video', '#^https?://.+?\.(' . join( '|', wp_get_video_extensions() ) . ')$#i', apply_filters( 'wp_video_embed_handler', 'wp_embed_handler_video' ), 9999 );
}

/**
 * The Google Video embed handler callback.
 *
 * Google Video does not support oEmbed.
 *
 * @see WP_Embed::register_handler()
 * @see WP_Embed::shortcode()
 *
 * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
 * @param array  $attr    Embed attributes.
 * @param string $url     The original URL that was matched by the regex.
 * @param array  $rawattr The original unmodified attributes.
 * @return string The embed HTML.
 */
function wp_embed_handler_googlevideo( $matches, $attr, $url, $rawattr ) {
	// If the user supplied a fixed width AND height, use it
	if ( !empty($rawattr['width']) && !empty($rawattr['height']) ) {
		$width  = (int) $rawattr['width'];
		$height = (int) $rawattr['height'];
	} else {
		list( $width, $height ) = wp_expand_dimensions( 425, 344, $attr['width'], $attr['height'] );
	}

	/**
	 * Filter the Google Video embed output.
	 *
	 * @since 2.9.0
	 *
	 * @param string $html    Google Video HTML embed markup.
	 * @param array  $matches The RegEx matches from the provided regex.
	 * @param array  $attr    An array of embed attributes.
	 * @param string $url     The original URL that was matched by the regex.
	 * @param array  $rawattr The original unmodified attributes.
	 */
	return apply_filters( 'embed_googlevideo', '<embed type="application/x-shockwave-flash" src="http://video.google.com/googleplayer.swf?docid=' . esc_attr($matches[2]) . '&amp;hl=en&amp;fs=true" style="width:' . esc_attr($width) . 'px;height:' . esc_attr($height) . 'px" allowFullScreen="true" allowScriptAccess="always" />', $matches, $attr, $url, $rawattr );
}

/**
 * YouTube iframe embed handler callback.
 *
 * Catches YouTube iframe embed URLs that are not parsable by oEmbed but can be translated into a URL that is.
 *
 * @since 4.0.0
 *
 * @global WP_Embed $wp_embed
 *
 * @param array  $matches The RegEx matches from the provided regex when calling
 *                        wp_embed_register_handler().
 * @param array  $attr    Embed attributes.
 * @param string $url     The original URL that was matched by the regex.
 * @param array  $rawattr The original unmodified attributes.
 * @return string The embed HTML.
 */
function wp_embed_handler_youtube( $matches, $attr, $url, $rawattr ) {
	global $wp_embed;
	$embed = $wp_embed->autoembed( "https://youtube.com/watch?v={$matches[2]}" );

	/**
	 * Filter the YoutTube embed output.
	 *
	 * @since 4.0.0
	 *
	 * @see wp_embed_handler_youtube()
	 *
	 * @param string $embed   YouTube embed output.
	 * @param array  $attr    An array of embed attributes.
	 * @param string $url     The original URL that was matched by the regex.
	 * @param array  $rawattr The original unmodified attributes.
	 */
	return apply_filters( 'wp_embed_handler_youtube', $embed, $attr, $url, $rawattr );
}

/**
 * Audio embed handler callback.
 *
 * @since 3.6.0
 *
 * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
 * @param array  $attr Embed attributes.
 * @param string $url The original URL that was matched by the regex.
 * @param array  $rawattr The original unmodified attributes.
 * @return string The embed HTML.
 */
function wp_embed_handler_audio( $matches, $attr, $url, $rawattr ) {
	$audio = sprintf( '[audio src="%s" /]', esc_url( $url ) );

	/**
	 * Filter the audio embed output.
	 *
	 * @since 3.6.0
	 *
	 * @param string $audio   Audio embed output.
	 * @param array  $attr    An array of embed attributes.
	 * @param string $url     The original URL that was matched by the regex.
	 * @param array  $rawattr The original unmodified attributes.
	 */
	return apply_filters( 'wp_embed_handler_audio', $audio, $attr, $url, $rawattr );
}

/**
 * Video embed handler callback.
 *
 * @since 3.6.0
 *
 * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
 * @param array  $attr    Embed attributes.
 * @param string $url     The original URL that was matched by the regex.
 * @param array  $rawattr The original unmodified attributes.
 * @return string The embed HTML.
 */
function wp_embed_handler_video( $matches, $attr, $url, $rawattr ) {
	$dimensions = '';
	if ( ! empty( $rawattr['width'] ) && ! empty( $rawattr['height'] ) ) {
		$dimensions .= sprintf( 'width="%d" ', (int) $rawattr['width'] );
		$dimensions .= sprintf( 'height="%d" ', (int) $rawattr['height'] );
	}
	$video = sprintf( '[video %s src="%s" /]', $dimensions, esc_url( $url ) );

	/**
	 * Filter the video embed output.
	 *
	 * @since 3.6.0
	 *
	 * @param string $video   Video embed output.
	 * @param array  $attr    An array of embed attributes.
	 * @param string $url     The original URL that was matched by the regex.
	 * @param array  $rawattr The original unmodified attributes.
	 */
	return apply_filters( 'wp_embed_handler_video', $video, $attr, $url, $rawattr );
}