/********************************************
 * Author  :  G. Jongerius   Version: 0.1
 * Filename:  ajax.js
 * Package :  com.jsoft
 *
 * Description:
 *   This Javascript file is designed for use in the com.jsoft web applications.
 *   Copyright (C) 2007 Jong-Soft
 */

function Ajax(url)
{
  this.url = url;

  this.isCallback  = false;
  this.isConnected = false;
  this.isPending   = false;
  this.isAsynchronize = false;
  this.useCallback = false;

  this.xmlHttp  = false;
  this.protocal = "GET";
}

Ajax.prototype.oncalldone = function (responseText)
{
  this.response = responseText;
};

Ajax.prototype.setUrl = function(url)
{
  this.url = url;
};

Ajax.prototype.getResponse = function ()
{
  if (this.isConnected)
    return this.xmlHttp.responseText;
  return "";
};

Ajax.prototype.setCallbackFunction = function(callBackFunction, callBackParams)
{
  this.callBackFunction  = callBackFunction;
  this.callBackParams    = callBackParams;
  this.useCallback       = true;
};

Ajax.prototype.setAsynchronize = function (flag)
{
  if (flag==true)
    this.isAsynchronize = true;
  else
    this.isAsynchronize = false;
};

/**
 * Create a call to the preset url with all the settings known to the object
 * pending on if the call is synchronize or not it will wait in this function.
 */
Ajax.prototype.callUrl = function ()
{
  if (!this.isPending)
    this.createAjaxObject();

  var self = this;
  this.xmlHttp.open(this.protocal, this.url, this.isAsynchronize);
  this.xmlHttp.onreadystatechange = function()
  {
    if (self.xmlHttp.readyState == 4)
    {
      self.callDone();
    }
  }
  this.isConnected = true;
  this.xmlHttp.send(null);

  if (this.isAsynchronize)
    this.callDone();
};

/**
 * Make a call to the webserver to preload information needed later on
 * in the website.
 *
 * This is always asynchronize.
 */
Ajax.prototype.preLoad = function (storeIn)
{
  var storeObject = null;
  try
  {
    storeObject = (storeIn instanceof HTMLElement) ? storeIn : document.getElementById(storeIn);
  }
  catch (err)
  {
    storeObject = (storeIn.nodeType && storeIn.nodeType === 1) ? storeIn : document.getElementById(storeIn);
  }

  this.oncalldone = function (responseContent)
  {
    storeObject.innerHTML = responseContent;
  }
  this.setAsynchronize(true);
  this.callUrl();
};

/**
 * Function that is called automatically when the call to the web server
 * is done. This function will either call the callback function set
 * or raise the internal event.
 */
Ajax.prototype.callDone = function()
{
  if (!this.isConnected)
    return;

  if (this.xmlHttp.status != 200)
    this.xmlHttp.responseText = 'An internal server error occured. Please contact the administrator.';

  if (this.useCallback)
    eval(this.callBackFunction +"('"+ escape(this.xmlHttp.responseText) +"')");
  else
    this.oncalldone(this.xmlHttp.responseText);
};

/**
 * Create the ajax object needed to make the Ajax calls to the webserver.
 * If this function fails no Ajax will be supported for the website.
 */
Ajax.prototype.createAjaxObject = function()
{
  if (!this.xmlHttp)
  {
    try
    {
      this.xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e)
    {
      try
      {
        this.xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (e)
      {
        this.xmlHttp = false;
      }
    }

    if (!this.xmlHttp && typeof XMLHttpRequest!='undefined')
    {
      this.xmlHttp = new XMLHttpRequest();
    }
  }

  if (this.xmlHttp) this.isPending = true;
};

/**
 * Submit the given form to the given url
 */
function doAjaxFormSubmit(formName, url, callBackFunction, callBackParams)
{
  var oForm = document.getElementById(formName);
  
  for (i = 0; i < oForm.elements.length; i++)
  {
    if (url.indexOf('?') == -1) 
      url += "?";
    else 
      url += "&";
    url += oForm.elements[i].name + "=" + oForm.elements[i].value;
  }
  
  var response = ajaxCall(url);
  if (response.length > 0)
  {
    if (response.indexOf('http') == 0)
    {
      document.location.href = response;
    }
    else
    {
      eval(callBackFunction +"(" + callBackParams +",'"+ escape(response) +"')");
    }
  }
}