/////////////////////////////////////////////////////////////
//
// AJAX in-house framework utility methods used on DDCS drill-down and Store Finder
//	 These methods below are an attempt to establishing a kind of home-grown 
//   AJAX framework for use on efollett.com. Below is common, shared functionality 
//   for DDCS drill-down and Store Finder
//
/////////////////////////////////////////////////////////////

var AjaxQueue = {
	batchSize: 1, //No.of simultaneous AJAX requests allowed, Default : 1
	urlQueue: [], //Request URLs will be pushed into this array
	elementsQueue: [], //Element IDs of elements to be updated on completion of a request ( as in Ajax.Updater )
	optionsQueue: [], //Request options will be pushed into this array
	setBatchSize: function(bSize){ //Method to set a different batch size. Recommended: Set batchSize before making requests
		this.batchSize = bSize;
	},
	push: function(url, options, elementID){ //Push the request in the queue. elementID is optional and required only for Ajax.Updater calls
		this.urlQueue.push(url);
		this.optionsQueue.push(options);
		//alert(options);
		if(elementID!=null){
			this.elementsQueue.push(elementID);
		} else {
			this.elementsQueue.push("NOTSPECIFIED");
		}

		this._processNext();
	},
	_processNext: function() { // Method for processing the requests in the queue. Private method. Don't call it explicitly
		if(Ajax.activeRequestCount < AjaxQueue.batchSize) // Check if the currently processing request count is less than batch size
		{
			if(AjaxQueue.elementsQueue.first()=="NOTSPECIFIED")  { //Check if an elementID was specified
				// Call Ajax.Request if no ElementID specified
				//Call Ajax.Request on the first item in the queue and remove it from the queue
				new Ajax.Request(AjaxQueue.urlQueue.shift(), AjaxQueue.optionsQueue.shift()); 

				var junk = AjaxQueue.elementsQueue.shift();
			} else {
				// Call Ajax.Updater if an ElementID was specified.
				//Call Ajax.Updater on the first item in the queue and remove it from the queue
				new Ajax.Updater(AjaxQueue.elementsQueue.shift(), AjaxQueue.urlQueue.shift(), AjaxQueue.optionsQueue.shift());
			}
		}
	}
};

Ajax.Responders.register({
  //Call AjaxQueue._processNext on completion ( success / failure) of any AJAX call.
  onComplete: AjaxQueue._processNext
});

/**
  Utility method which invokes ajax request with the supplied HTTP url parameters
  The AJAX-enabled page should have an iframe with id 'otherdata'. Also, an error 
  javascript method will be invoked upon errors
*/
function getData(params, elementId) {
  if(Ajax.getTransport()) {
  	AjaxQueue.push(uri,{method: 'get', parameters: params, onFailure: error, onComplete: doneLoaded}, elementId);  		
  }
}