var lift_ajaxQueue = [];
var lift_ajaxInProcess = null;
var lift_ajaxShowing = false;
var lift_ajaxRetryCount = 3
                       
function lift_ajaxHandler(theData, theSuccess, theFailure) {
  var toSend = {retryCnt: 0};
  toSend.when = (new Date()).getTime();
  toSend.theData = theData;
  toSend.onSuccess = theSuccess;
  toSend.onFailure = theFailure;
  
  lift_ajaxQueue.push(toSend);
  lift_ajaxQueueSort();
  lift_doAjaxCycle();
  return false; // buttons in forms don't trigger the form
}

function lift_ajaxQueueSort() {
  lift_ajaxQueue.sort(function (a,b) {return a.when - b.when;});
}

function lift_defaultFailure() {
alert('The server cannot be contacted at this time');
}

function lift_startAjax() {
  lift_ajaxShowing = true;

}

function lift_endAjax() {
  lift_ajaxShowing = false;

}

function lift_testAndShowAjax() {
  if (lift_ajaxShowing && lift_ajaxQueue.length == 0 &&
      lift_ajaxInProcess == null) {
   lift_endAjax();
      } else if (!lift_ajaxShowing && (lift_ajaxQueue.length > 0 ||
     lift_ajaxInProcess != null)) {
   lift_startAjax();
     }
}

function lift_doAjaxCycle() {
  var queue = lift_ajaxQueue;
  if (queue.length > 0) {
    var now = (new Date()).getTime();
    if (lift_ajaxInProcess == null && queue[0].when <= now) {
      var aboutToSend = queue.shift();

      lift_ajaxInProcess = aboutToSend;
      var  successFunc = function() {
         lift_ajaxInProcess = null;
         if (aboutToSend.onSuccess) {
           aboutToSend.onSuccess();
         }
         lift_doAjaxCycle();
      };

      var failureFunc = function() {
         lift_ajaxInProcess = null;
         var cnt = aboutToSend.retryCnt;
         if (cnt < lift_ajaxRetryCount) {
	   aboutToSend.retryCnt = cnt + 1;
           var now = (new Date()).getTime();
           aboutToSend.when = now + (1000 * Math.pow(2, cnt));
           queue.push(aboutToSend);
           lift_ajaxQueueSort();
         } else {
           if (aboutToSend.onFailure) {
             aboutToSend.onFailure();
           } else {
             lift_defaultFailure();
           }
         }
         lift_doAjaxCycle();
      };
      lift_actualAjaxCall(aboutToSend.theData, successFunc, failureFunc);
    }
  }

  lift_testAndShowAjax();
  setTimeout("lift_doAjaxCycle();", 200);
}

function lift_actualAjaxCall(data, onSuccess, onFailure) {
jQuery.ajax({ url : '/ajax_request', data : data, type : 'POST', dataType : 'script', timeout : 5000, cache : false, success : onSuccess, error : onFailure });
}

jQuery(document).ready(function() {lift_doAjaxCycle()});