<?php

/**

 * API for fetching the HTML to embed remote content based on a provided URL.

 * Used internally by the {@link WP_Embed} class, but is designed to be generic.

 *

 * @link http://codex.wordpress.org/oEmbed oEmbed Codex Article

 * @link http://oembed.com/ oEmbed Homepage

 *

 * @package WordPress

 * @subpackage oEmbed

 */

/**

 * oEmbed class.

 *

 * @package WordPress

 * @subpackage oEmbed

 * @since 2.9.0

 */

class WP_oEmbed {

	var $providers = array();

	/**

	 * Constructor

	 *

	 * @uses apply_filters() Filters a list of pre-defined oEmbed providers.

	 */

	function __construct() {

		// List out some popular sites that support oEmbed.

		// The WP_Embed class disables discovery for non-unfiltered_html users, so only providers in this array will be used for them.

		// Add to this list using the wp_oembed_add_provider() function (see its PHPDoc for details).

		$this->providers = apply_filters( 'oembed_providers', array(

			'http://youtu.be/*'                                  => array( 'http://www.youtube.com/oembed',                     false ),

			'http://blip.tv/*'                                   => array( 'http://blip.tv/oembed/',                            false ),

			'http://qik.com/*'                                   => array( 'http://qik.com/api/oembed.{format}',                false ),

			'http://revision3.com/*'                             => array( 'http://revision3.com/api/oembed/',                  false ),

			'http://i*.photobucket.com/albums/*'                 => array( 'http://photobucket.com/oembed',                     false ),

			'http://gi*.photobucket.com/groups/*'                => array( 'http://photobucket.com/oembed',                     false ),

			'http://wordpress.tv/*'                              => array( 'http://wordpress.tv/oembed/',                       false ),

			'#https?://(www\.)?twitter.com/.+?/status(es)?/.*#i' => array( 'http://api.twitter.com/1/statuses/oembed.{format}', true  ),

		) );

		// Fix any embeds that contain new lines in the middle of the HTML which breaks wpautop().

	}

	/**

	 * The do-it-all function that takes a URL and attempts to return the HTML.

	 *

	 * @see WP_oEmbed::discover()

	 * @see WP_oEmbed::fetch()

	 * @see WP_oEmbed::data2html()

	 *

	 * @param string $url The URL to the content that should be attempted to be embedded.

	 * @param array $args Optional arguments. Usually passed from a shortcode.

	 * @return bool|string False on failure, otherwise the UNSANITIZED (and potentially unsafe) HTML that should be used to embed.

	 */

	function get_html( $url, $args = '' ) {

		$provider = false;

		if ( !isset($args['discover']) )

			$args['discover'] = true;

		foreach ( $this->providers as $matchmask => $data ) {

			list( $providerurl, $regex ) = $data;

			// Turn the asterisk-type provider URLs into regex

				$matchmask = '#' . str_replace( '___wildcard___', '(.+)', preg_quote( str_replace( '*', '___wildcard___', $matchmask ), '#' ) ) . '#i';

			if ( preg_match( $matchmask, $url ) ) {

				$provider = str_replace( '{format}', 'json', $providerurl ); // JSON is easier to deal with than XML

				break;

			}

		}

		if ( !$provider && $args['discover'] )

			$provider = $this->discover( $url );

		if ( !$provider || false === $data = $this->fetch( $provider, $url, $args ) )

			return false;

		return apply_filters( 'oembed_result', $this->data2html( $data, $url ), $url, $args );

	}

	/**

	 * Attempts to find oEmbed provider discovery <link> tags at the given URL.

	 *

	 * @param string $url The URL that should be inspected for discovery <link> tags.

	 * @return bool|string False on failure, otherwise the oEmbed provider URL.

	 */

	function discover( $url ) {

		$providers = array();

		// Fetch URL content

		if ( $html = wp_remote_retrieve_body( wp_remote_get( $url ) ) ) {

			// <link> types that contain oEmbed provider URLs

			$linktypes = apply_filters( 'oembed_linktypes', array(

				'application/json+oembed' => 'json',

				'text/xml+oembed' => 'xml',

				'application/xml+oembed' => 'xml', // Incorrect, but used by at least Vimeo

			) );

			// Strip <body>

			$html = substr( $html, 0, stripos( $html, '</head>' ) );

			// Do a quick check

			$tagfound = false;

			foreach ( $linktypes as $linktype => $format ) {

				if ( stripos($html, $linktype) ) {

					$tagfound = true;

					break;

				}

			}

			if ( $tagfound && preg_match_all( '/<link([^<>]+)>/i', $html, $links ) ) {

				foreach ( $links[1] as $link ) {

					$atts = shortcode_parse_atts( $link );

					if ( !empty($atts['type']) && !empty($linktypes[$atts['type']]) && !empty($atts['href']) ) {

						$providers[$linktypes[$atts['type']]] = $atts['href'];

						// Stop here if it's JSON (that's all we need)

						if ( 'json' == $linktypes[$atts['type']] )

							break;

					}

				}

			}

		}

		// JSON is preferred to XML

		if ( !empty($providers['json']) )

			return $providers['json'];

		elseif ( !empty($providers['xml']) )

			return $providers['xml'];

		else

			return false;

	}

	/**

	 * Connects to a oEmbed provider and returns the result.

	 *

	 * @param string $provider The URL to the oEmbed provider.

	 * @param string $url The URL to the content that is desired to be embedded.

	 * @param array $args Optional arguments. Usually passed from a shortcode.

	 * @return bool|object False on failure, otherwise the result in the form of an object.

	 */

	function fetch( $provider, $url, $args = '' ) {

		$args = wp_parse_args( $args, wp_embed_defaults() );

		$provider = add_query_arg( 'maxwidth', (int) $args['width'], $provider );

		$provider = add_query_arg( 'maxheight', (int) $args['height'], $provider );

		$provider = add_query_arg( 'url', urlencode($url), $provider );

		foreach( array( 'json', 'xml' ) as $format ) {

			$result = $this->_fetch_with_format( $provider, $format );

			if ( is_wp_error( $result ) && 'not-implemented' == $result->get_error_code() )

				continue;

			return ( $result && ! is_wp_error( $result ) ) ? $result : false;

		}

		return false;

	}

	/**

	 * Fetches result from an oEmbed provider for a specific format and complete provider URL

	 *

	 * @since 3.0.0

	 * @access private

	 * @param string $provider_url_with_args URL to the provider with full arguments list (url, maxheight, etc.)

	 * @param string $format Format to use

	 * @return bool|object False on failure, otherwise the result in the form of an object.

	 */

	function _fetch_with_format( $provider_url_with_args, $format ) {

		$provider_url_with_args = add_query_arg( 'format', $format, $provider_url_with_args );

		$response = wp_remote_get( $provider_url_with_args );

		if ( 501 == wp_remote_retrieve_response_code( $response ) )

			return new WP_Error( 'not-implemented' );

		if ( ! $body = wp_remote_retrieve_body( $response ) )

			return false;

		$parse_method = "_parse_$format";

		return $this->$parse_method( $body );

	}

	/**

	 * Parses a json response body.

	 *

	 * @since 3.0.0

	 * @access private

	 */

	function _parse_json( $response_body ) {

		return ( ( $data = json_decode( trim( $response_body ) ) ) && is_object( $data ) ) ? $data : false;

	}

	/**

	 * Parses an XML response body.

	 *

	 * @since 3.0.0

	 * @access private

	 */

	function _parse_xml( $response_body ) {

	}

	/**

	 * Converts a data object from {@link WP_oEmbed::fetch()} and returns the HTML.

	 *

	 * @param object $data A data object result from an oEmbed provider.

	 * @param string $url The URL to the content that is desired to be embedded.

	 * @return bool|string False on error, otherwise the HTML needed to embed.

	 */

	function data2html( $data, $url ) {

		if ( ! is_object( $data ) || empty( $data->type ) )

			return false;

		$return = false;

		switch ( $data->type ) {

			case 'photo':

				if ( empty( $data->url ) || empty( $data->width ) || empty( $data->height ) )

					break;

				if ( ! is_string( $data->url ) || ! is_numeric( $data->width ) || ! is_numeric( $data->height ) )

					break;

				$title = ! empty( $data->title ) && is_string( $data->title ) ? $data->title : '';

				$return = '<a href="' . esc_url( $url ) . '"><img src="' . esc_url( $data->url ) . '" alt="' . esc_attr($title) . '" width="' . esc_attr($data->width) . '" height="' . esc_attr($data->height) . '" /></a>';

				break;

			case 'video':

			case 'rich':

				if ( ! empty( $data->html ) && is_string( $data->html ) )

					$return = $data->html;

				break;

			case 'link':

				if ( ! empty( $data->title ) && is_string( $data->title ) )

					$return = '<a href="' . esc_url( $url ) . '">' . esc_html( $data->title ) . '</a>';

				break;

			default:

				$return = false;

		}

		// You can use this filter to add support for custom data types or to filter the result

		return apply_filters( 'oembed_dataparse', $return, $data, $url );

	}

	/**

	 * Strip any new lines from the HTML.

	 *

	 * @access private

	 * @param string $html Existing HTML.

	 * @param object $data Data object from WP_oEmbed::data2html()

	 * @param string $url The original URL passed to oEmbed.

	 * @return string Possibly modified $html

	 */

	function _strip_newlines( $html, $data, $url ) {

		if ( false !== strpos( $html, "\n" ) )

			$html = str_replace( array( "\r\n", "\n" ), '', $html );

		return $html;

	}

}

/**

 * Returns the initialized {@link WP_oEmbed} object

 *

 * @since 2.9.0

 * @access private

 *

 * @see WP_oEmbed

 * @uses WP_oEmbed

 *

 * @return WP_oEmbed object.

 */

	static $wp_oembed;

	if ( is_null($wp_oembed) )

		$wp_oembed = new WP_oEmbed();

	return $wp_oembed;

}