/*
 * JavaScript-Code for displaying a popup wnd when clicking on a twitter intend link.
 *
 * Source of these JavaScript functions is the twitter api documentation where one is
 * told to include the script file http://platform.twitter.com/widgets.js OR the code
 * below to implement twitter intends.
 */

(

  function() {

    if (window.__twitterIntentHandler) return;
    var intentRegex = /twitter\.com(\:\d{2,4})?\/intent\/(\w+)/,
        windowOptions = 'scrollbars=yes,resizable=yes,toolbar=no,location=yes',
        width = 550,
        height = 420,
        winHeight = screen.height,
        winWidth = screen.width;

    function handleIntent(e) {
      e = e || window.event;
      var target = e.target || e.srcElement, m, left, top;
      while (target && target.nodeName.toLowerCase() !== 'a') {
        target = target.parentNode;
      }
      if (target && target.nodeName.toLowerCase() === 'a' && target.href) {
        m = target.href.match(intentRegex);
        if (m) {
          left = Math.round((winWidth / 2) - (width / 2));
          top = 0;
          if (winHeight > height) {
            top = Math.round((winHeight / 2) - (height / 2));
          }
          window.open(target.href, 'intent', windowOptions + ',width=' + width +
                                             ',height=' + height + ',left=' + left + ',top=' + top);
          e.returnValue = false;
          e.preventDefault && e.preventDefault();
        }
      }
    }

    if (document.addEventListener) {
      document.addEventListener('click', handleIntent, false);
    } else if (document.attachEvent) {
      document.attachEvent('onclick', handleIntent);
    }
    window.__twitterIntentHandler = true;

  }()

);