(function() {
	// jQuery.browser is deprecated, but this is a quick way to check for IE6
	if (jQuery.browser.msie && jQuery.browser.version.substring(0,1) === '6') {
		return;
	}
	
	// quick check for the existence - not value of - the metrics cookie
	function has_metrics_cookie() {
		return document.cookie.indexOf("sp_metrics_context=") >= 0;
	}

	var bartender_url = 'http://metrics.aws.sitepoint.com/bartender';

	var original_referrer = SPMetrics_options['original_referrer'];
	
	var group = SPMetrics_options['group'];
	
	var regex = new RegExp('');

	var engines = ["google\\."];

	var valid_referrer = false;
	for (var i in engines) {
		regex.compile('^http://(www\.)?' + engines[i], 'i');
		valid_referrer = original_referrer.match(regex);
		// stop looking for matches as soon as we've got a valid referrer
		if (valid_referrer != false) {
			break;
		}
	}
	// only let them through if they have come from a search engine we're tracking,
	// and have never been presented the ad before
	if (valid_referrer != false && !has_metrics_cookie()) {
		var url = document.location.toString();
		var context = SPMetrics_options['context'];
		var category = SPMetrics_options['category'];

		var opts = {
			'referrer': original_referrer,
			'url': url,
			'context': context,
			'category': category,
			'group': group
		}

		jQuery.get(bartender_url, opts, null, 'script');
		
	}

})();