var ajaxCaller = {
	
	statusMsg:'',
    shouldDebug: false,
    shouldEscapeVars: false,
    shouldMakeHeaderMap: true,

    calls: new Array(),
    pendingResponseCount: 0,

    /**************************************************************************
    PUBLIC METHODS
    *************************************************************************/

    getXML: function(url, callbackFunction) {
        this.get(url, null, callbackFunction, true, null);
    },

    getPlainText: function(url, callbackFunction) {
        this.get(url, null, callbackFunction, false, null);
    },

    postForPlainText: function(url, vars, callbackFunction, callingContext) {
        this.postVars(url, vars, null, callbackFunction, false,
                    callingContext, "POST", null, null, null);
    },

    postForXML: function(url, vars, callbackFunction) {
        this.postVars(url, vars, null, callbackFunction, true,
                    null, "POST", null, null, null);
    },

    get: function(url, urlVars, callbackFunction, expectingXML, callingContext) {
        this._callServer(url, urlVars, callbackFunction, expectingXML,
                    callingContext, "GET", null, null, null);
    },

    postVars:
    function(url, bodyVars, optionalURLVars, callbackFunction, expectingXML, callingContext) {
        this._callServer(url, optionalURLVars, callbackFunction, expectingXML,
                      callingContext, "POST", bodyVars, null, null);
    },

    postBody:
    function(url, optionalURLVars, callbackFunction, expectingXML,
             callingContext, bodyType, body) {
        this._callServer(url, optionalURLVars, callbackFunction, expectingXML,
                      callingContext, "POST", null, bodyType, body);
    },

    putBody:
    function(url, optionalURLVars, callbackFunction, expectingXML,
             callingContext, bodyType, body) {
        this._callServer(url, optionalURLVars, callbackFunction, expectingXML,
                      callingContext, "PUT", null, bodyType, body);
    },

    options:
    function(url, optionalURLVars, callbackFunction, expectingXML,
             callingContext, bodyType, body) {
        this._callServer(url, optionalURLVars, callbackFunction, expectingXML,
                      callingContext, "OPTIONS", null, bodyType, body);
    },

    trace:
    function(url, optionalURLVars, callbackFunction, expectingXML,
             callingContext, bodyType, body) {
        this._debug("trace");
        this._callServer(url, optionalURLVars, callbackFunction, expectingXML,
                      callingContext, "TRACE", null, bodyType, body);
    },

    deleteIt: function(url, urlVars, callbackFunction,
                     expectingXML, callingContext) {
        this._callServer(url, urlVars, callbackFunction, expectingXML,
                    callingContext, "DELETE", null, null, null);
    },

    head: function(url, urlVars, callbackFunction, expectingXML, callingContext) {
        this._callServer(url, urlVars, callbackFunction, expectingXML,
                    callingContext, "HEAD", null, null, null);
    },

    /**************************************************************************
    PRIVATE METHODS
    *************************************************************************/
    // added by netu: statusMsg: if passed, show "ajaj loading image"
    _callServer: function(url, urlVars, callbackFunction, expectingXML,
                       callingContext, requestMethod, bodyVars,
                       explicitBodyType, explicitBody) {

        if (urlVars == null) {
            urlVars = new Array();
        }
		
		// add 
		urlVars['__isajax']='1';
		
		// if csrf token is set pass it to ajax
		if (document.getElementById('_CTKN_')) {
			urlVars['_CTKN_']=document.getElementById('_CTKN_').value;
		}
		
        this._debug("_callServer() called. About to request URL\n"
                + "call key: [" + this.calls.length + "]\n"
                + "url: [" + url + "]\n"
                + "callback function: [" + callbackFunction + "]\n"
                + "treat response as xml?: [" + expectingXML + "]\n"
                + "Request method?: [" + requestMethod + "]\n"
                + "calling context: [" + callingContext + "]\n"
                + "explicit body type: [" + explicitBodyType + "]\n"
                + "explicit body: [" + explicitBody + "]\n"
                + "urlVars: [" + util.describe(urlVars) + "]\n"
                + "bodyVars: [" + util.describe(bodyVars) + "]"
              );


        var xReq = this._createXMLHttpRequest();
		
        xReq.onreadystatechange = function() {
            ajaxCaller._onResponseStateChange(call);
        }

        var call = { xReq: xReq,
            callbackFunction: callbackFunction,
            expectingXML: expectingXML,
            callingContext: callingContext,
            url: url
        };

        if (urlVars != null) {
            var urlVarsString = this._createHTTPVarSpec(urlVars);
            if (urlVarsString.length > 0) { // TODO check if appending with & instead
                url += "?" + urlVarsString;
            }
        }

        xReq.open(requestMethod, url, true);
        if (this.statusMsg) { this._AjaxLoadingShow(this.statusMsg); }

        if (requestMethod == "GET"
        || requestMethod == "HEAD"
        || requestMethod == "DELETE") {
            this._debug("Body-less request to URL " + url);
            xReq.send(null);
            return;
        }

        if (requestMethod == "POST"
        || requestMethod == "PUT"
        || requestMethod == "OPTIONS"
        || requestMethod == "TRACE") {
            bodyType = null;
            body = null;
            if (explicitBodyType == null) { // It's a form
                bodyType = 'application/x-www-form-urlencoded; charset=UTF-8';
                body = this._createHTTPVarSpec(bodyVars);
            } else {
                bodyType = explicitBodyType;
                body = explicitBody;
            }
            this._debug("Content-Type: [" + bodyType + "]\nBody: [" + body + "].");
            xReq.setRequestHeader('Content-Type', bodyType);
            xReq.send(body);
            return;
        }

        this._debug("ERROR: Unknown Request Method: " + requestMethod);


    },

    // The callback of xmlHttpRequest is a dynamically-generated function which
    // immediately calls this function.
    _onResponseStateChange: function(call) {

        xReq = call.xReq;

        if (xReq.readyState < 4) { //Still waiting
            return;
        }

        if (xReq.readyState == 4) { //Transmit to actual callback
            //added by netu
            this._AjaxLoadingHide();
            
            this._debug("Call " + util.describe(call)
                + " with context [" + call.callingContext + "]"
                + " to " + call.url + " has returned.");
            callbackFunction = call.callbackFunction;
            if (!callbackFunction) { // Maybe still loading, e.g. in another JS file
                setTimeout(function() {
                    _onResponseStateChange(call);
                }, 100);
            }
            var content = call.expectingXML ? xReq.responseXML : xReq.responseText;
            responseHeaders = xReq.getAllResponseHeaders();
            headersForCaller = this.shouldMakeHeaderMap ?
            this._createHeaderMap(responseHeaders) : responseHeaders;
            callbackFunction(content, headersForCaller, call.callingContext);

            
            
        }

        call = null; // Technically the responsibility of GC
        this.pendingResponseCount--;

    },

    // Browser-agnostic factory function
    _createXMLHttpRequest: function() {
        if (window.XMLHttpRequest) {
            return new XMLHttpRequest();
        } else if (window.ActiveXObject) {
            return new ActiveXObject('Microsoft.XMLHTTP')
        } else {
            _error("Could not create XMLHttpRequest on this browser");
            return null;
        }
    },

    _createHTTPVarSpec: function(vars) {
        var varsString = "";
        for (key in vars) {
            var value = vars[key];
            if (this.shouldEscapeVars) {
                escapePlusRE = new RegExp("\\\+");
                value = value.replace(escapePlusRE, "%2B");
            }
            varsString += '&' + key + '=' + value;
        }
        if (varsString.length > 0) {
            varsString = varsString.substring(1); // chomp initial '&'
        }
        this._debug("Built var String: " + varsString)
        return varsString;
    },

    /* Creates associative array from header type to header */
    _createHeaderMap: function(headersText) {
        extractedHeaders = headersText.split("\n");
        delete extractedHeaders[extractedHeaders.length]; // Del blank line at end
        headerMap = new Array();
        for (i = 0; i < extractedHeaders.length - 2; i++) {
            head = extractedHeaders[i];
            fieldNameEnding = head.indexOf(":");
            field = head.substring(0, fieldNameEnding);
            value = head.substring(fieldNameEnding + 2, head.length);
            value = value.replace(/\s$/, "");
            headerMap[field] = value;
        }
        return headerMap;
    },

    _debug: function(message) {

        if (this.shouldDebug) {
            alert("AjaxJS Message:\n\n" + message);
        }
    },

    _error: function(message) {
        this._AjaxLoadingHide();
        if (this.shouldDebug) {
            alert("AjaxJS ERROR:\n\n" + message);
        }
    },
	
	//functions added by netu
	_AjaxLoadingShow: function (msg, doc) {
	
		if (!doc) {
			doc = document;
		}
	
		if (doc.getElementById('ajaxHourglass')) {
			//alert('showing img');
			doc.getElementById('ajaxMessage').innerHTML = msg;
			doc.getElementById('ajaxHourglass').style.display = "inline";
		}
	
	},
	
	_AjaxLoadingHide: function (doc) {
	
		if (!doc) {
			doc = document;
		}
		if (doc.getElementById('ajaxHourglass')) {
			doc.getElementById('ajaxMessage').innerText = '';
			doc.getElementById('ajaxHourglass').style.display = "none";
			//doc.getElementById('ajaxLoadingImg').src = '';
			//parent.document.getElementById('ajaxLoading').style.visibility="hidden";
		}
		
	}


};