var _ga = _ga || {};
var _gaq = _gaq || [];
_ga.trackSocial = function(opt_pageUrl, opt_trackerName) {
  _ga.trackFacebook(opt_pageUrl, opt_trackerName);
  _ga.trackTwitter(opt_pageUrl, opt_trackerName);
};
_ga.trackFacebook = function(opt_pageUrl, opt_trackerName) {
  var trackerName = _ga.buildTrackerName_(opt_trackerName);
  try {
    if (FB && FB.Event && FB.Event.subscribe) {
      FB.Event.subscribe('edge.create', function(targetUrl) {
        _gaq.push([trackerName + '_trackSocial', 'facebook', 'like',
            targetUrl, opt_pageUrl]);
      });
      FB.Event.subscribe('edge.remove', function(targetUrl) {
        _gaq.push([trackerName + '_trackSocial', 'facebook', 'unlike',
            targetUrl, opt_pageUrl]);
      });
      FB.Event.subscribe('message.send', function(targetUrl) {
        _gaq.push([trackerName + '_trackSocial', 'facebook', 'send',
            targetUrl, opt_pageUrl]);
      });
    }
  } catch (e) {}
};
_ga.buildTrackerName_ = function(opt_trackerName) {
  return opt_trackerName ? opt_trackerName + '.' : '';
};
_ga.trackTwitter = function(opt_pageUrl, opt_trackerName) {
  var trackerName = _ga.buildTrackerName_(opt_trackerName);
  try {
    if (twttr && twttr.events && twttr.events.bind) {
      twttr.events.bind('tweet', function(event) {
        if (event) {
          var targetUrl;
          if (event.target && event.target.nodeName == 'IFRAME') {
            targetUrl = _ga.extractParamFromUri_(event.target.src, 'url');
          }
          _gaq.push([trackerName + '_trackSocial', 'twitter', 'tweet',
            targetUrl, opt_pageUrl]);
        }
      });
    }
  } catch (e) {}
};
_ga.extractParamFromUri_ = function(uri, paramName) {
  if (!uri) {
    return;
  }
  var uri = uri.split('#')[0];
  var parts = uri.split('?');
  if (parts.length == 1) {
    return;
  }
  var query = decodeURI(parts[1]);

  // Find url param.
  paramName += '=';
  var params = query.split('&');
  for (var i = 0, param; param = params[i]; ++i) {
    if (param.indexOf(paramName) === 0) {
      return unescape(param.split('=')[1]);
    }
  }
  return;
};