// holds an instance of XMLHttpRequest
var xmlHttp = createXmlHttpRequestObject();

// when set to true, display detailed error messages
var showErrors = false;
// initialize the validation requests cache 
var cache = new Array();


// creates an XMLHttpRequest instance
function createXmlHttpRequestObject() 
{
  // will store the reference to the XMLHttpRequest object
  var xmlHttp;
  // this should work for all browsers except IE6 and older
  try
  {
    // try to create XMLHttpRequest object
    xmlHttp = new XMLHttpRequest();
  }
  catch(e)
  {
    // assume IE6 or older
    var XmlHttpVersions = new Array("MSXML2.XMLHTTP.6.0",
                                    "MSXML2.XMLHTTP.5.0",
                                    "MSXML2.XMLHTTP.4.0",
                                    "MSXML2.XMLHTTP.3.0",
                                    "MSXML2.XMLHTTP",
                                    "Microsoft.XMLHTTP");
    // try every id until one works
    for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++) 
    {
      try 
      { 
        // try to create XMLHttpRequest object
        xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
      } 
      catch (e) {} // ignore potential error
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
    displayError("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}

// function that displays an error message
function displayError($message)
{
  // ignore errors if showErrors is false
  if (showErrors)
  {
    // turn error displaying Off
    showErrors = false;
    // display error message
 
    alert("Error encountered: \n" + $message);
    // retry validation after 10 seconds
    setTimeout("validate();", 10000);
  }
}

// the function handles the validation for any form field
function validate(method, inputValue, fieldID)
{
    // only continue if xmlHttp isn't void
  if (xmlHttp)
  {
    // if we received non-null parameters, we add them to cache in the
    // form of the query string to be sent to the server for validation
    if (fieldID)
    {
      // encode values for safely adding them to an HTTP request query string
      inputValue = encodeURIComponent(inputValue);
      fieldID = encodeURIComponent(fieldID);
      // add the values to the queue
      cache.push("method="+method+"&value=" + inputValue + "&name=" + fieldID);
    }
    // try to connect to the server
    try
    {
      // continue only if the XMLHttpRequest object isn't busy
      // and the cache is not empty
      if ((xmlHttp.readyState == 4 || xmlHttp.readyState == 0) && cache.length > 0)
      {
        // get a new set of parameters from the cache
        var cacheEntry = cache.shift();
        // make a server request to validate the extracted data
        xmlHttp.open("POST", serverAddress, true);
        xmlHttp.setRequestHeader("Content-Type", 
                                 "application/x-www-form-urlencoded");
        xmlHttp.onreadystatechange = handleRequestStateChange;
        xmlHttp.send(cacheEntry);
      }
    }
    catch (e)
    {
      // display an error when failing to connect to the server
      displayError(e.toString());
    }
  }
}

function get_places(aValue, aNextElement, aNumber) {
  if (xmlHttp) {
    if (aValue && aNextElement) {
      aValue = encodeURIComponent(aValue);
      aNextElement = encodeURIComponent(aNextElement);
      aNumber = encodeURIComponent(aNumber);
      cache.push("method=places&id_parent=" + aValue + "&element="+aNextElement+"&number="+aNumber);
    }

    try {
      if ((xmlHttp.readyState == 4 || xmlHttp.readyState == 0) && cache.length > 0)
      {
        // get a new set of parameters from the cache
        var cacheEntry = cache.shift();

        // make a server request to validate the extracted data
        xmlHttp.open("POST", serverAddress, true);
        xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xmlHttp.onreadystatechange = function() {
          if (xmlHttp.readyState == 4) {
            if (xmlHttp.status == 200) {
              try {
                read_get_places_response();
              } catch(e) {
                displayError(e.toString());
              }
            } else {
            }
          } 
        }; // EO onreadystatechange

        xmlHttp.send(cacheEntry);
      }
    } catch (e) {
      displayError(e.toString());
    }
  }
}

// function that handles the HTTP response
function handleRequestStateChange() 
{
  // when readyState is 4, we read the server response
  if (xmlHttp.readyState == 4) 
  {
    // continue only if HTTP status is "OK"
    if (xmlHttp.status == 200) 
    {
      try
      {
        // read the response from the server
        readResponse();
      }
      catch(e)
 
      {
        // display error message
        displayError(e.toString());
      }
    }
    else
    {
      // display error message
      displayError(xmlHttp.statusText);
    }
  }
}

// read server's response 
function readResponse()
{
  // retrieve the server's response 
  var response = xmlHttp.responseText;
  // server error?
  if (response.indexOf("ERRNO") >= 0 || response.indexOf("error:") >= 0 || response.length == 0) throw(response.length == 0 ? "Server error." : response);
  responseXml = xmlHttp.responseXML;
  // get the document element
  xmlDoc = responseXml.documentElement;

  
  if (xmlDoc.getElementsByTagName("result") && xmlDoc.getElementsByTagName("result").length >= 0 && xmlDoc.getElementsByTagName("result")[0].firstChild) {
  	result = xmlDoc.getElementsByTagName("result")[0].firstChild.data;
  } else {
  	result = "";
  }  

	if (xmlDoc.getElementsByTagName("fieldid")) {
		fieldID = xmlDoc.getElementsByTagName("fieldid")[0].firstChild.data;
	} else {
		fieldId = '';
	}

 	// find the HTML element that displays the error
 	message = document.getElementById("error-"+fieldID);

 	if (message) {
	  // show the error or hide the error
	  message.innerHTML = result;
 	}

// call validate() again, in case there are values left in the cache
    setTimeout("validate();", 500);
}

// read server's response 
function read_get_places_response()
{
  // retrieve the server's response 
  var response = xmlHttp.responseText;

  // server error?
  if (response.indexOf("ERRNO") >= 0 || response.indexOf("error:") >= 0 || response.length == 0) throw(response.length == 0 ? "Server error." : response);

  responseXml = xmlHttp.responseXML;

	if (responseXml) {
	  xmlDoc = responseXml.documentElement;
	  elements = xmlDoc.getElementsByTagName("destination");

		if (xmlDoc.getElementsByTagName("element").length > 0) {
          // next element 
        element = xmlDoc.getElementsByTagName("element")[0].firstChild.data; 
		number = xmlDoc.getElementsByTagName("number")[0].firstChild.data; 
		iparent = xmlDoc.getElementsByTagName("parent")[0].firstChild.data; 

            if (element && elements.length > 0 && number) {
        		number = parseInt(number) + 1;
        		iparent = parseInt(iparent);

                    // Get the DIV
                htmlelement = document.getElementById('restinations');
				var loader = document.getElementById('loader');

				if (loader) {
					loader.innerHTML = '';
				}

                // creaste a new selectlist with given name
                listbox = document.createElement("select");
                listbox.name = element+'[]';
                listbox.className = 'form_common';
	            listbox.setAttribute('onchange', 'document.getElementById(\'selectedcityname\').innerHTML =\'\';document.getElementById(\'selectedcity\').value =\'\';clearPlaceLists('+number+');get_places(this.value, \''+element+'\', '+number+')');
				

                listbox.options[0] = new Option ("", "");
                // add items to selectlist
                for (i = 0; i < elements.length; i++) {
                    var destination = elements[i].getAttribute("name");
                    var id = elements[i].getAttribute("id");
                    
                    listbox.options[i+1] = new Option(destination, id);
                }       
            
        		if (document.getElementById(element+number)) {
            		div = document.getElementById(element+number);
            		div.innerHTML = "";
        		} else {
					div = document.createElement("div");
					div.id = element+number;
        		}
            		
               	div.appendChild(listbox);       

				if (number == 2) {
					nlink = document.createElement('a');
					nlink.setAttribute('href', '');					
					nlink.setAttribute('onclick', 'window.open(\'/places/popup/'+iparent+'\', \'find-city\', \'status=0,toolbar=0,width=600,height=400\'); return false;');					
					ntext = document.createTextNode('Etsi kaupunki');
					space = document.createTextNode(' ');
					nlink.appendChild(space);
					nlink.appendChild(ntext);
					div.appendChild(nlink);
				}                    

	    		if (!document.getElementById(element+number)) {
					htmlelement.appendChild(div);
				}
            } else {
            }
		} else {
		}
//		document.forms["stop"].elements[element]
//		  alert(elements.length;);
	}

// call validate() again, in case there are values left in the cache
    setTimeout("validate();", 500);
}

function clearPlaceLists(id) {
	var prefix = 'destination';
	var maxOfElements = 4;
	for (var i = id+1; i < maxOfElements; i++) {
		var element = document.getElementById(prefix+i);
		
		if (element) {
			element.innerHTML = '';
		}
	}
}

// sets focus on the first field of the form
function setFocus()    
{
  document.getElementById("txtUsername").focus();
}

function removeTrip(id, message, address, text) {
	var confirm = window.confirm(message);
	var element = document.getElementById(id);

	if (element && confirm) {

      // only continue if xmlHttp isn't void
      if (xmlHttp)
      {
          // try to connect to the server
        try
        {
          if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
          {

            // make a server request to validate the extracted data
            xmlHttp.open("GET", address, true);
            xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            xmlHttp.onreadystatechange = function() {

              // when readyState is 4, we read the server response
              if (xmlHttp.readyState == 4) 
              {
                // continue only if HTTP status is "OK"
                if (xmlHttp.status == 200) 
                {
                  try
                  {
                  	element.innerHTML = text;
                  }
                  catch(e)
                  {
                    displayError(e.toString());
                  }
                }
             }

            };
            xmlHttp.send(null);
          }
        }
        catch (e)
        {
          displayError(e.toString());
        }
      }
  
  }
	
	return false;
}