(function () {
  var promo_id = 4041,
      old_key = "calendar_widget",
      initialized_attr = "tpcalendarinitialized",
      target_src = function(prams){ return "https://aswidgets.travelpayouts.com/calendar_widget/iframe.js" },
      klit_params_map = { 'shmarker': 'marker' },
      ref = document.getElementsByTagName('script');
  
  for (var i = 0, len = ref.length; i < len; i++) {
    var script = ref[i];
    var src = script.getAttribute('src');
    var matches = src && src.match(new RegExp("promo_id="+ promo_id + "|" + old_key));

    if (src && !script.getAttribute('script-initialized') && matches) {
      script.setAttribute('script-initialized', true);

      function getParams() {
        var params = {};
        script.src.replace(/[?&]+([^=&]+)=([^&]*)/gi, function (m, key, value) {
          params[key] = decodeURIComponent(value);
        });
        return params;
      }
      
      var url_params = getParams(),
          js = document.createElement('script'),
          isOldEMBED = (matches[0] == old_key);

      if(!isOldEMBED){
        for (var source in klit_params_map) {
          if (klit_params_map.hasOwnProperty(source)) {
            var target = klit_params_map[source];
            url_params[target] = url_params[source];
            delete(url_params[source]);
          }
        }
      }
   
      if(isOldEMBED){
        js.setAttribute(initialized_attr, 'true');
        js.setAttribute('script-initialized', 'true');
      }

      var params = [];
      for (var name in url_params) {
        if (url_params.hasOwnProperty(name)) {
          params.push(name + "=" + encodeURIComponent(url_params[name]))
        }
      }
      target_src_string = target_src(url_params);
      var separator = (target_src_string.indexOf('?') === -1 ? '?' : '&');
      js.src = target_src_string + separator + params.join('&');
      script.parentNode.insertBefore(js, script);

      break;
    }
  }
})();