(function() {
	// Visitor id cookie
	var COOKIE_NAME = 'webs-stats-visitor-id';
	var COOKIE_DURATION = 1; // days

	var data = window.webs && webs.stats;
	if(!data) {
		return;
	}
	var url = data.collectorUrl;
	if(!url) {
		return;
	}
	delete data.collectorUrl;
	var newUrl = data.newCollectorUrl;
	if (newUrl) {
		delete data.newCollectorUrl;
	}

	data.referrer = document.referrer;
	data.location = window.location.href;

	data.visitorId = getVisitorId();

	var qs = '?' + (function() {
		var list = [];
		for(var k in data) {
			list.push('' + encodeURIComponent(k) + '=' + encodeURIComponent(data[k]));
		}
		return list.join('&');
	})();

	var img = document.createElement('img');
	img.setAttribute('src', url + qs);
	img.setAttribute('height', 1);
	img.setAttribute('width', 1);
	img.style.position = 'fixed';
	img.style.left = '0px';
	img.style.bottom = '0px';
	document.body.appendChild(img);

	if(newUrl) {
		var newCollectorImg = document.createElement('img');
		newCollectorImg.setAttribute('src', newUrl + qs);
		newCollectorImg.setAttribute('height', 1);
		newCollectorImg.setAttribute('width', 1);
		newCollectorImg.style.position = 'fixed';
		newCollectorImg.style.left = '0px';
		newCollectorImg.style.bottom = '0px';
		document.body.appendChild(newCollectorImg);
	}

	function getVisitorId() {
		var vid = readCookie(COOKIE_NAME);
		if(vid) {
			return vid;
		}

		vid = Math.floor(Math.random() * 1000000000);
		createCookie(COOKIE_NAME, vid, COOKIE_DURATION);
		return vid;
	}

	// Cookie utils
	// http://www.quirksmode.org/js/cookies.html
	function createCookie(name, value, days) {
		var expires;
		if(days) {
			var date = new Date();
			date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
			expires = '; expires=' + date.toGMTString();
		} else {
			expires = '';
		}
		document.cookie = name + '=' + value + expires + '; path=/';
	}

	function readCookie(name) {
		var nameEQ = name + '=';
		var ca = document.cookie.split(';');
		for(var i = 0; i < ca.length; i++) {
			var c = ca[i];
			while(c.charAt(0) == ' ') {
				c = c.substring(1, c.length);
			}
			if(c.indexOf(nameEQ) === 0) {
				return c.substring(nameEQ.length, c.length);
			}
		}
		return null;
	}

	function eraseCookie(name) {
		createCookie(name, '', -1);
	}
})();