/*
Author/Owner: 	Daniel Peel.
Contact: 		mintpants@tiscali.co.uk.
Details:		Ajax Object.
Requires:       Base.js
Created: 		25.10.07
Updated: 		1.11.07
20.01.08 - 	Moved Augment function to the core jscript script
Removed the parse tabs Augmentation(tabberAutomatic())
21.02.08 - 	Converted to a class giving more flexibility and simplicity to different uses of ajax
added callback functionailty to deal with the request result
25.11.08 - 	Removed the loading messge functionality, moved to its own functions (see macros at bottom of class)
as changing the messages style within the ajax object was not atomic, and problems with "this" reference.
Added a preload event to be defined when calling the object.
Added an example use at the bottom of the file.
*/

//Requires innerWindow, scrolled, divScreenCenter, Augment, and base
function Ajax() {

    //********************  create ajaxObject  *********************//
    this.jaxObj = false;

    //firefox, netscape or safari
    if (window.XMLHttpRequest) {
        this.jaxObj = new XMLHttpRequest();
    }
    //interent explorer
    else if (window.ActiveXObject) {
        this.jaxObj = new ActiveXObject("Microsoft.XMLHTTP");
    }
    //*******************  end ajaxObject  *************************//

    this.Response = new Array();

}

Ajax.prototype.callBack = function(responseText) {

    //Cleanup if we havent been overwriiten
    responseText = null;
    this.jaxObj = null;
}

Ajax.prototype.preLoad = function() {

}

//**************************************************************//
//					  GET data ajax request                     //

//requires the response div object not just a reference
Ajax.prototype.getData = function(source, extraArgs) {

    this.args = Augment({
        noneForNow: false
    }, extraArgs);

    if (this.jaxObj) {
        this.jaxObj.open("GET", source);

        var self = this;

        this.jaxObj.onreadystatechange = function() {

            //has the data been retrieved
            if (self.jaxObj.readyState == 4 && self.jaxObj.status == 200) {
                self.callBack(self.jaxObj.responseText);               
            }
            else {
                self.preLoad();
            }
        }

        //send the request
        this.jaxObj.send(null);
    }
} //end get data source

//***************************************************************//
//					   POST data ajax request                    //

//requires the response div object not just a reference
Ajax.prototype.postData = function(url, data, extraArgs) {

    this.args = Augment({
        noneforNow: false
    }, extraArgs);

    if (this.jaxObj) {
        this.jaxObj.open("POST", url);
        this.jaxObj.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
        this.jaxObj.setRequestHeader("Content-length", data.length);
        this.jaxObj.setRequestHeader("Connection", "close");

        var self = this;

        this.jaxObj.onreadystatechange = function() {

            //has the data been retrieved
            if (self.jaxObj.readyState == 4 && self.jaxObj.status == 200) {
                self.callBack(self.jaxObj.responseText);    
            }
            else {
                self.preLoad();
            }
        }

        //send the request
        this.jaxObj.send(data);

    } //End if JaxObject
}    //end post data source


//************************************ MACRO **************************************//
//*********************************************************************************//

function AjaxLoadMessage(loadingDivId, parentNodeId, loadImgRelUrl, messageText) {

    var loadingDiv, loadingTxt, loadingImg;

    //Only load the loader once
    if (ById(loadingDivId) != null) {
        return;
    }
    //Create the wrapper
    loadingDiv = document.createElement("div");
    loadingDiv.setAttribute("id", loadingDivId);
    loadingDiv.style.position = 'absolute';
    loadingDiv.style.visibility = 'hidden';
    loadingDiv.style.top = '0px';
    loadingDiv.style.left = '0px';
    loadingDiv.style.textAlign = 'center';
    loadingDiv.style.fontSize = "12px";
    loadingDiv.style.color = '#999999';

    //Create the load image
    loadingImg = document.createElement("img");
    loadingImg.setAttribute("src", loadImgRelUrl);

    //Append to the wrapper
    loadingDiv.appendChild(loadingImg);

    //Create the load message
    if (messageText != false) {
        spacer = document.createElement("div");
        spacer.setAttribute("id", loadingDivId + "_prometheus_spacer");
        //spacer.style.marginBottom = '3px;' //throws an exception in ie
        loadingDiv.appendChild(spacer);

        loadingTxt = document.createTextNode(messageText);
        //Append to wrapper
        loadingDiv.appendChild(loadingTxt);
    }


    //Append the wrapper to the DOM so we can access its offset properties
    document.body.appendChild(loadingDiv);

    if (parentNodeId == 'body') {
        //load the inner window size
        innerWindowSize();

        loadingDiv.style.padding = "20px";

        loadingDiv.style.top = divScreenCenter(loadingDiv.offsetWidth, loadingDiv.offsetHeight).verCent + "px";
        loadingDiv.style.left = divScreenCenter(loadingDiv.offsetWidth, loadingDiv.offsetHeight).horCent + "px";

        loadingDiv.style.backgroundColor = "#ffffff";
        loadingDiv.style.border = "1px solid #000000";

    }
    else {
        var pNode = ById(parentNodeId);
        pNode.appendChild(loadingDiv);

        loadingDiv.style.position = null;
        loadingDiv.style.top = null;
        loadingDiv.style.left = null;
        loadingDiv.style.width = 'inherit';
        //Center the loadingDiv withint the parent wrapper
        loadingDiv.style.marginTop = (pNode.offsetHeight / 2) - (loadingDiv.offsetHeight / 2) + "px";
    }

    //Show the loading div
    loadingDiv.style.visibility = 'visible';

}

function AjaxRemoveLoadMessage(loadingDivId, parentNodeId) {

    if (parentNodeId == 'body') {
        document.body.removeChild(ById(loadingDivId));
    }
    else {
        ById(parentNodeId).removeChild(ById(loadingDivId));
    }

}


//*********************************************************************************//
//******************************* EXAMPLE USE *************************************//
/*
function AjaxEample(statusText, statusBttn, id)
{	
var statusObj = ById(statusText);
var bttnObj = ById(statusBttn);
	
var loadingDivId 	= "processingStatusReq";
var parentNodeId 	= "body";
var loadImgRelUrl 	= "../img/ajax-loader.gif";
var messageText 	= "loading";
	
jax = new Ajax();	
	
jax.preLoad = function()	{		
AjaxLoadMessage(loadingDivId, parentNodeId, loadImgRelUrl, messageText);	
}
		
jax.callBack = function(responseText)	{
	
AjaxRemoveLoadMessage(loadingDivId, parentNodeId);
		
if(responseText.indexOf('success', 0) > -1)
{
if(statusObj.innerHTML == 'Yes')
{
statusObj.innerHTML = 'No';
bttnObj.innerHTML = '<img src="../images/activate_bttn.jpg" />';
}
else
{
statusObj.innerHTML = 'Yes';
bttnObj.innerHTML = '<img src="../images/deactivate_bttn.jpg" />';
}
}
else
{
alert("Sorry, a system error occured, if the problem persists please contact the website administrator.");
}
		
}
			
var postStr = "submit=true&id="+encodeURI(id);
jax.postData("ajax_updateDlStatus.php", postStr);		
	
}
*/