// JS document

function getXmlHttpRequest() {
	var httpRequest = null;
	try {
		httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
	}
	
	catch (e){
		try {
			httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
		}
		
		catch (e) {
			httpRequest = null;
		}
	}
	
	if (!httpRequest && typeof XMLHttpRequest != "undefined") {
		httpRequest = new XMLHttpRequest();
	}
	
	return httpRequest;
}

function getUrlSync(url) {
	return getUrl(url, false, null);
}

function getUrlAsync(url, handleStateChange) {
	return getUrl(url, true, handleStateChange);
}


// call a url
function getUrl(url, async, handleStateChange) {
	
	var xmlHttpReq = getXmlHttpRequest();

	if (!xmlHttpReq)
		return;

	if (handleStateChange) {
		xmlHttpReq.onreadystatechange = function() {
				handleStateChange(xmlHttpReq);
			};
	} else {
	  xmlHttpReq.onreadystatechange = function() {;}
	}
	
	xmlHttpReq.open("GET", url, async);
	xmlHttpReq.send(null);
}

function postUrl(url, data, async, stateChangeCallback) { 

   var xmlHttpReq = getXmlHttpRequest(); 

	if (!xmlHttpReq)
		return;

	xmlHttpReq.open("POST", url, async);
	xmlHttpReq.onreadystatechange = function() {
			stateChangeCallback(xmlHttpReq);
		};
	xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	xmlHttpReq.send(data);
	//alert ('url: ' + url + '\ndata: ' + data);
}

function urlEncodeDict(dict) { 
  var result = "";
  for (var i=0; i<dict.length; i++) {
    result += "&" + encodeURIComponent(dict[i].name) + "=" + encodeURIComponent(dict[i].value);
  }
  
  return result;
}

function execOnSuccess(stateChangeCallback) {

  return function(xmlHttpReq) {
    if (xmlHttpReq.readyState == 4 &&
	xmlHttpReq.status == 200)
      stateChangeCallback(xmlHttpReq);
    //alert('IN execOnSuccess' + xmlHttpReq + " " + xmlHttpReq.readyState + " " + xmlHttpReq.status);
  };
}

function postFormByForm(form, async, successCallback) {
	var formVars = new Array();
	
	for (var i = 0; i < form.elements.length; i++) {
	  var formElement = form.elements[i];
	  
	  // Special handling for checkboxes or radio buttons (we need an array of selected checkboxes..)!
	  if((formElement.type == 'checkbox' || formElement.type == 'radio') && !formElement.checked) {
	    continue;
	  } 
	  
	  // special handling for radio button
	  
	  if(formElement.type == 'radio' ) { 

	    
	  }
	  
	  var v=new Object;
	  v.name=formElement.name;
	  v.value=formElement.value;
	  formVars.push(v);
	  // alert('n:' + v.name + '\nv:' + v.value);		
	} 
	postUrl(form.action, urlEncodeDict(formVars), async, execOnSuccess(successCallback));
}

function postForm(formName, async, successCallback) {
  // postFormByName
  var form = document.forms[formName];
  return postFormByForm(form, async, successCallback);
}

function replaceDivContents(xmlHttpRequest, dstDivId) {
  var dstDiv = document.getElementById(dstDivId);
  dstDiv.innerHTML = xmlHttpRequest.responseText;
}


function getUrlXMLResponseCallback(xmlHttpReq) {
  
  if(xmlHttpReq.responseXML == null) {
    alert("Error while processing your request.");
    return;
  }
  var root_node = getRootNode(xmlHttpReq);
  var return_code = getNodeValue(root_node, 'return_code');
  //alert("return code " + return_code);
  
  if(return_code == 0) {
    redirect_val = getNodeValue(root_node, 'redirect_on_success');
    if(redirect_val != null) {
      window.location=redirect_val;
    } else {
      success_message = getNodeValue(root_node, 'success_message');
      if (success_message != null) {
	alert(success_message);
      }
      if(this.successCallback != null) {
	this.successCallback(xmlHttpReq);
      }
    }
  } else {
    var error_msg = getNodeValue(root_node, 'error_message');
    if (error_msg == null || error_msg.length == 0) {
      if(return_code==2) {
	error_msg = "You must be logged in to perform this operation.";
      } else {
	error_msg = "An error occured while performing this operation.";
      }
    }
    alert(error_msg);
  }
}

function getUrlXMLResponseCallbackFillDiv(xmlHttpReq) {
  getUrlXMLResponseCallback(xmlHttpReq);
  document.getElementById(this.div_id).innerHTML=getNodeValue(xmlHttpReq.responseXML, "html_content");
}

function getNodeValue(obj,tag) {
  node=obj.getElementsByTagName(tag);
  if(node!=null && node.length>0) {
    return node[0].firstChild.nodeValue;
  } else {
    return null;
  }
}

function getRootNode(xmlHttpReq) {
  return xmlHttpReq.responseXML.getElementsByTagName('root')[0];
}

function getUrlXMLResponse(url, successCallback) {
  
  this.successCallback = successCallback;
  this.urlResponseCallback = getUrlXMLResponseCallback;
  getUrl(url, true, execOnSuccess(this.urlResponseCallback));
  
}

function getUrlXMLResponseAndFillDiv(url, div_id, successCallback) {
  this.successCallback = successCallback;
  this.urlResponseCallback = getUrlXMLResponseCallbackFillDiv;
  this.div_id = div_id;
  getUrl(url, true, execOnSuccess(this.urlResponseCallback));
}

function postUrlXMLResponse(url, data, successCallback) {

    this.successCallback = successCallback;
    this.urlResponseCallback = getUrlXMLResponseCallback;
    postUrl(url, data, true, execOnSuccess(this.urlResponseCallback));
}

function confirmAndPostUrlXMLResponse(url, confirmMessage, data, successCallback) {
  if (confirm(confirmMessage)) {
    postUrlXMLResponse(url, data, successCallback);
  }
}

function postFormXMLResponse(formName, successCallback) {
	
  this.successCallback = successCallback;
  postForm(formName, true, execOnSuccess(getUrlXMLResponseCallback));
}