// ==UserScript==
// @name          Facebook desktop notification
// @namespace     https://www.schtobia.de/
// @version       0.2.8
// @description   Facebook desktop notification (based on HTML5)
// @author        Tobias Schmidl
// @include       http*://www.facebook.com/*
// @include       http*://m.facebook.com/*
// @include       http*://facebook.com/*
// @grant         GM_getValue
// @run-at        document-end
// @downloadURL   https://github.com/schtobia/greasemonkey/raw/master/facebook-notification.user.js
// @updateURL     https://github.com/schtobia/greasemonkey/raw/master/facebook-notification.user.js
// ==/UserScript==
//

var Notification = window.Notification || window.mozNotification || window.webkitNotification;

var friendRequestsElement = document.getElementById("requestsCountValue");
var messagesElement = document.getElementById("mercurymessagesCountValue");
var notificationsElement = document.getElementById("notificationsCountValue");
var newFriendRequests = 0;
var newMessages = 0;
var newNotifications = 0;

var lastFriendRequests = 0;
var lastMessages = 0;
var lastNotifications = 0;
var notificationInstance = null;

var timeout = GM_getValue("timeout", 10000);

var intervalID = null;

notify = function()
{
	if (friendRequestsElement == null || messagesElement == null || notificationsElement == null)
	{
		console.log(GM_info.script.name + ": One of the DOM nodes is empty! Clearing the interval timer " + intervalID + "!");
		clearInterval(intervalID);
		intervalID = null;
		return;
	}

	newFriendRequests = friendRequestsElement.innerHTML;
	newMessages = messagesElement.innerHTML;
	newNotifications = notificationsElement.innerHTML;

	if (newFriendRequests > lastFriendRequests || newMessages > lastMessages || newNotifications > lastNotifications)
	{
		var msg= " ";

		if (newFriendRequests > lastFriendRequests)
			msg = msg + "| " + (newFriendRequests - lastFriendRequests) + " new Friend Request(s) |";

		if (newMessages > lastMessages)
			msg = msg + "| " + (newMessages - lastMessages) + " new Message(s) |";

		if (newNotifications > lastNotifications)
			msg = msg + "| " + (newNotifications - lastNotifications) + " new Notification(s) |";

		console.log(GM_info.script.name + ": Trying to set notification...", msg);

		notificationInstance = new Notification("Facebook (" + newFriendRequests + '|' + newMessages + '|' + newNotifications + ')',
			{
				"dir" : "auto",
				"body" : msg,
				"icon" : document.baseURI + "/favicon.ico",
				"lang" : "en-US"
			}
		)

		lastFriendRequests = newFriendRequests;
		lastMessages = newMessages;
		lastNotifications = newNotifications;
	}
}

registerNotification = function()
{
	Notification.requestPermission(function(grantedPermission){
		if (grantedPermission === "granted")
		{
			console.log(GM_info.script.name + ": permission granted");
			intervalID = setInterval(notify, timeout);
			console.log(GM_info.script.name + ": intervalID: " + intervalID);
		}
		else
		{
			console.log(GM_info.script.name + ": permission NOT granted");
		}
	});
}

/* Normal flow of operations below! */
if (!Notification)
{
	alert("Notifications are not supported for this browser version yet.");
}
else
	registerNotification();