background.js

function getHostname()
{
    return localStorage["hostname"] || "apple-tv.local";
}

function getPlayPosition()
{
    return localStorage["play-position"] || "current";
}

// reads and parses a query string
function readQueryString(qs)
{
	qs = qs.split("+").join(" ");
	var params = {}, tokens, re = /[?&]?([^=]+)=([^&]*)/g;
	while(tokens = re.exec(qs)) params[decodeURIComponent(tokens[1])] = decodeURIComponent(tokens[2]);
	return params;
}

function getYouTubeVideoInfo(video_id)
{
	var prefix = "https://"
	//var el_types = ["&el=embedded", "&el=detailpage", "&el=vevo", ""];
//	for(var i in el_types)
//	{
		var request = new XMLHttpRequest();
		var requesturl = prefix+"www.youtube.com/get_video_info?&video_id=" + video_id //+ el_types[i]
		+"&eurl=http%3A%2F%2Fwww%2Eyoutube%2Ecom%2F&sts=1588";
		request.open('GET', requesturl, false);
		request.send(); // synchronous requests! don't tell mom

		if(request.status === 200)
		{
			var q = readQueryString(request.responseText);

			// if it has a token it's good enough
			if(q.token)
				return q;
		}
//	}

	// can't get vidya info
	return null;
}

function getYouTubeVideoUrlObject(video_info, quality)
{
	if(video_info.conn && video_info.conn.startsWith('rtmp')) return video_info.conn;
	else if(video_info.url_encoded_fmt_stream_map && video_info.url_encoded_fmt_stream_map.length > 1)
	{
		var url_data = [];
		var url_data_strs = video_info.url_encoded_fmt_stream_map.split(',');
		var url_data_sort_func = (function(a,b) { return b.itag - a.itag; });
		var url_data_get_quality = (function(quality) {
			for(var i in url_data)
			{
				var url_info = url_data[i];
				if(url_info.quality == quality)
					return url_info;
			}
			return url_data[0];
		});
		for(var i in url_data_strs)
		{
			var url_info = readQueryString(url_data_strs[i]);
			fmt = parseFlashVariables(url_data_strs[i]);

			url_info.url = url_info.url.replace(/^https/, "http");

			if(url_info.sig)
				url_info.url += '&signature=' + url_info.sig;
			else if(fmt.s)
				url_info.url += "&signature=" + decodeSignature(fmt.s);

			if(url_info.url
				&& url_info.itag
				&& url_info.type.lastIndexOf("video/mp4;",0) === 0 // we want only MP4 streams
				&& parseInt(url_info.itag) < 82 // we don't want 3D
			){
				url_data.push(url_info);
			}
		}
		url_data.sort(url_data_sort_func);

		if(quality != undefined && quality != null)
		{
			if(quality == "best") {
				console.log("Sending video format " + url_data[0].type + " itag=" + url_data[0].itag + " to AppleTV at " + getHostname())
				return url_data[0];
			}
			else if(quality == "worst") return url_data[url_data.length - 1];
			else return url_data_closest_quality(quality);
		}
		else return url_data;
	}
	else console.log("Don't understand video info.");

	return;
}

function decodeSignature(s) {
	s = s.split("");
	s = s.slice(2);
	s = s.reverse();
	s = s.slice(3);
	var t = s[0];
	s[0] = s[19%s.length];
	s[19] = t;
	s = s.reverse();
	return s.join("");
}

function parseWithRegExp(text, regex, processValue) { // regex needs 'g' flag
	var obj = {};
	if(!text) return obj;
	if(processValue === undefined) processValue = function(s) {return s;};
	var match;
	while(match = regex.exec(text)) {
		obj[match[1]] = processValue(match[2]);
	}
	return obj;
}
function parseFlashVariables(s) {return parseWithRegExp(s, /([^&=]*)=([^&]*)/g);}

chrome.contextMenus.removeAll();
chrome.contextMenus.create({
    "type":"normal",
    "title":"AirPlay it!",
    "contexts":["link", "video"],
    "onclick": function (info, tab) {
		if (typeof info.linkUrl !== 'undefined') { // link clicked
			console.log("Right click - Sending url: " + info.linkUrl + " mediaType: " + info.mediaType)
			startPlaying(info.linkUrl, info.mediaType)
		}
		else if (info.mediaType === 'video') { // HTML5 video clicked
			console.log("Right click - Sending video: " + info.srcUrl)
			startPlaying(info.srcUrl, info.mediaType)
		}
    }
});

var playback_started = false // to avoid terminating playback before video loads
var terminate_loop = false

function airplay(url, position) {
	// Use position based on user options (or fallback to given position)
	position = getPlayPosition() === "current" ? position : 0;

    var xhr = new XMLHttpRequest();
	var hostname = getHostname()
    var port = ":7000";
    if(/: \d + $ / .test(hostname)) port = "";

	// stop currently playing video
	var xhr_stop = new XMLHttpRequest();
	xhr_stop.open("POST", "http://" + hostname + port + "/stop", true, "AirPlay", null);
	xhr_stop.send(null);

    xhr.open("POST", "http://" + hostname + port + "/play", true, "AirPlay", null);

	playback_started = false;
	terminate_loop = false;

    xhr.addEventListener("load", function() { // set timer to prevent playback from aborting
		var timer = setInterval(function() {
			var xhr = new XMLHttpRequest();
			var playback_info_keys_count = 0; // 0 something wrong; 2 ready to play; >2 playing
			xhr.open("GET", "http://" + hostname + port + "/playback-info", true, "AirPlay", null);
			xhr.addEventListener("load", function() {
				playback_info_keys_count = xhr.responseXML.getElementsByTagName("key").length;
				console.log("playback: " + playback_started + "; keys: " + playback_info_keys_count)
				if (!playback_started && playback_info_keys_count > 2) { // if we're getting some actual playback info
					playback_started = true;
					console.log("setting playback_started = true")
					terminate_loop = false;
				}
				if (terminate_loop && playback_info_keys_count <= 2) { // playback terminated
					console.log("stopping loop & setting playback_started = false")
					clearInterval(timer);
					var xhr_stop = new XMLHttpRequest();
					xhr_stop.open("POST", "http://" + hostname + port + "/stop", true, "AirPlay", null);
					xhr_stop.send(null);
					playback_started = false;
				}
				if (playback_started && playback_info_keys_count == 2) { // playback stopped, AppleTV is "readyToPlay"
					console.log("sending /stop signal, setting playback_started = false")
					var xhr_stop = new XMLHttpRequest();
					xhr_stop.open("POST", "http://" + hostname + port + "/stop", true, "AirPlay", null);
					xhr_stop.send(null);
					playback_started = false;
					terminate_loop = true;
				}
			}, false);
			xhr.addEventListener("error", function() {clearInterval(timer);}, false);
			xhr.send(null);
		}, 5000);
	}, false);
    xhr.setRequestHeader("Content-Type", "text/parameters"); xhr.send("Content-Location: " + url +
    "\nStart-Position: " + position + "\n");
}

function parseYouTubeUrl(url) {
	var video_id = url.split('v=')[1];
	var ampersandPosition = video_id.indexOf('&');
	if(ampersandPosition != -1) {
		video_id = video_id.substring(0, ampersandPosition);
	}
	return video_id
}

function getYouTubeAirPlayUrl(youtube_url) {
	var video_id = parseYouTubeUrl(youtube_url)
	var video_info = getYouTubeVideoInfo(video_id);
	var video_url = getYouTubeVideoUrlObject(video_info, "best");

	var url = video_url.url
	if (/requiressl=yes/.test(url)) {
		url = url.replace(/^http:/, 'https:');
	}
	return url;
}

/**
 * Starts playing video from given position
 *
 * @param  {String} video_url       URL for the video
 * @param  {String} [content_type]  type of video
 * @param  {Number} [position]      starting position between 0 and 1
 */
function startPlaying(video_url, content_type, position) {
	content_type = typeof content_type === 'undefined' || content_type !== 'video' ? 'youtube' : 'video';
	position = position || 0;
	var airplay_url = video_url;
	if (content_type === 'youtube') {
		airplay_url = getYouTubeAirPlayUrl(video_url);
	}
  console.log("airplay_url: " + airplay_url);
	airplay(airplay_url, position);
}

function onRequest(request, sender, sendResponse) {
  // Show the page action for the tab that the sender (content script)
  // was on.
  chrome.pageAction.show(sender.tab.id);

  // Return nothing to let the connection be cleaned up.
  sendResponse({});
};

// Listen for the content script to send a message to the background page.
chrome.extension.onRequest.addListener(onRequest);

chrome.pageAction.onClicked.addListener(function(tab)
 {
	 console.log('Button clicked.');
	 var video;
	 chrome.tabs.sendMessage(tab.id, {action: "Html5Video"}, function(response) {
		 console.log('Response on HTML5 compatibility received');
		 video = response.Html5Video;
	     if (typeof video === 'undefined' || /^http(s?):\/\/(www\.)?youtube/.test(tab.url)) {
			 console.log('startPlaying YouTube');
			 startPlaying(tab.url) // YouTube url
	     } else {
			 console.log('startPlaying HTML5', video);
			 return startPlaying(video.url, 'video', video.position); // HTML5 video
	     }
	 });
 }
);

// some websites use HTML5 video if viewed on iPad
chrome.webRequest.onBeforeSendHeaders.addListener(
    function(info) {
        // Replace the User-Agent header
        var headers = info.requestHeaders;
        headers.forEach(function(header, i) {
            if (header.name.toLowerCase() == 'user-agent') {
                header.value = 'Mozilla/5.0 (iPad; CPU OS 7_0_4 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) Version/7.0 Mobile/11B554a Safari/9537.53'; // iPadify page to get HTML5 video
            }
        });
        return {requestHeaders: headers};
    },
    // Request filter
    {
        // Modify the headers for these pages
        urls: [
            "http://tune.pk/video/*",
			"http://www.xvideos.com/video*",
			"http://xhamster.com/movies/*"
        ],
        // In the main window and frames
        types: ["main_frame", "sub_frame"]
    },
    ["blocking", "requestHeaders"]
);