var xmlHttp = createXmlHttpRequestObject();
var mainImage = "";
var disabledControls = new Array();

function createXmlHttpRequestObject()
{
  var xmlHttp;
  
  try
  {
    xmlHttp = new XMLHttpRequest();
  }
  catch (e)
  {
    var XmlHttpVersions = new Array("Msxml2.XMLHTTP.6.0",
                                    "Msxml2.XMLHTTP.5.0",
				    "Msxml2.XMLHTTP.4.0",
				    "Msxml2.XMLHTTP.3.0", 
				    "Msxml2.XMLHTTP",
				    "Microsoft.XMLHTTP");
    for (var i = 0; i < XmlHttpVersions.length && !xmlHttp; i++)
    {
      try
      {
         xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
      }
      catch (e)
      {
      }
    }
  }
  
  if (!xmlHttp) {
    alert("Error creating the XMLHttpRequest object.");
  } else {
    return xmlHttp;
  }
}

function handleRequestStateChange()
{
  if (xmlHttp.readyState == 4)
  {
    if (xmlHttp.status == 200)
    {
      try
      {
        handleServerResponse();
      }
      catch (e)
      {
        alert ("Error reading the response: " + e.toString());
      }
    } else {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}

function handleServerResponse()
{
  for (i = 0; i < disabledControls.length; i++) {
    disabledControls[i].disabled = false;
  }

  disabledControls = new Array();
  
  var xmlResponse = xmlHttp.responseXML;
  
  if (!xmlResponse || !xmlResponse.documentElement) {
    throw("Invalid XML structure:\n" + xmlHttp.responseText);
  }
  
  var rootNodeName = xmlResponse.documentElement.nodeName;
  
  if (rootNodeName == "parsererror") {
    throw("Invalid XML structure:\n" + xmlHttp.responseText);
  }
  
  xmlRoot = xmlResponse.documentElement;

  if (rootNodeName != "response" || !xmlRoot.firstChild) {
    throw("Empty XML response:\n" + xmlHttp.responseText);
  }

  errorElement = xmlRoot.getElementsByTagName('error').item(0);
  
  if (!errorElement) {
    throw("response/error element expected:\n" + xmlHttp.responseText);
  }
  
  errorCodeElement = errorElement.getElementsByTagName('code').item(0);

  if (!errorCodeElement) {
    throw("response/error/code element expected:\n" + xmlHttp.responseText);
  }
  
  errorCode = errorCodeElement.firstChild.data;
  
  if (errorCode != '0') {
    errorDescription = errorElement.getElementsByTagName('description').item(0).firstChild.data;
    throw("Error response:\n" + errorDescription);
  }
  
  requestElement = xmlRoot.getElementsByTagName('request').item(0);

  if (!requestElement) {
    throw("response/request element expected:\n" + xmlHttp.responseText);
  }
  
  requestCommandElement = requestElement.getElementsByTagName('command').item(0);

  if (!requestCommandElement) {
    throw("response/request/command element expected:\n" + xmlHttp.responseText);
  }

  command = requestCommandElement.firstChild.data;
  
  requestActionElement = requestElement.getElementsByTagName('action').item(0);

  if (!requestActionElement) {
    throw("response/request/action element expected:\n" + xmlHttp.responseText);
  }

  action = requestActionElement.firstChild.data;
  
  answerElement = xmlRoot.getElementsByTagName('answer').item(0);

  if (!answerElement) {
    throw("response/answer element expected:\n" + xmlHttp.responseText);
  }
  
  switch (command) {
    case 'image':
      switch (action) {
        case 'get_url':
	  setImagesURL(answerElement);
	  break; // get_url
        case 'get_url_listing':
        	typesElement = xmlRoot.getElementsByTagName('types').item(0);
	  		setImagesURL_listing(typesElement,answerElement);
	  	break; // get_url_listing
      }
      break; // image
  }
}

function makeRequest(params, async)
{
  if (xmlHttp)
  {
    try
    {
      xmlHttp.open("GET", "requester.php?" + params, async);
      
      if (async) {
        xmlHttp.onreadystatechange = handleRequestStateChange;
      }
      
      xmlHttp.send(null);
      
      if (!async) {
        handleServerResponse();
      }
    }
    catch (e)
    {
      alert ("Can't connect to server:\n" + e.toString());
    }
  }
}

function setImagesURL(answerElement)
{
  aElement = document.getElementById("productImageA");
  bElement = document.getElementById("productImageB");
  if (aElement && bElement) {
    if (mainImage == "") {
      mainImage = aElement.innerHTML;
    }
    if (answerElement.firstChild.firstChild != null) {
      aElement.innerHTML = "<img src="+answerElement.firstChild.firstChild.data+">";
    } else {
      aElement.innerHTML = mainImage;
    }
    if ((answerElement.childNodes.length > 1) && (answerElement.childNodes[1].firstChild != null)) {
      bElement.innerHTML = "<img src="+answerElement.childNodes[1].firstChild.data+">";
    } else {
      bElement.innerHTML = "";
    }
  }
}

function setImagesURL_listing(typesElement,answerElement)
{
  pid = typesElement.firstChild.firstChild.data;
  aElement = document.getElementById("productImageA_"+pid);
  if (aElement) {
    if (mainImage == "") {
      mainImage = aElement.innerHTML;
    }
    if (answerElement.firstChild.firstChild != null) {
      aElement.innerHTML = "<img src="+answerElement.firstChild.firstChild.data+">";
    } else {
      aElement.innerHTML = mainImage;
    }
  }
}

function onOptionSelectChanged(pElement,pid)
{
  // listing
  var type = '';
  if (pid) {
  	products_id = pid;
  	type = '&type=thumb';
  	tableElement = document.getElementById("optionsTable_"+pid);
  	
  // info
  } else {
  	tableElement = document.getElementById("optionsTable");
  }
  
  selectArray = tableElement.getElementsByTagName("select");

  reqStr = "";
  for (i = 0; i < selectArray.length; i++) {
    disabledControls[disabledControls.length] = selectArray[i];
    selectArray[i].disabled = true;
    reqStr += (selectArray[i].name.match(/\d+/)+"-"+selectArray[i].value+",");
  }
  
  if (reqStr.length > 1) {
    reqStr = reqStr.substr(reqStr, reqStr.length - 1);
  }

  makeRequest('cmd_command=image&cmd_action=get_url&products_id=' + products_id + '&attributes='+ reqStr+type, true);
}

function onOptionRadioChanged(pElement)
{
  tableElement = document.getElementById("optionsTable");
  radioArray = tableElement.getElementsByTagName("input");
  reqStr = "";

  for (i = 0; i < radioArray.length; i++) {
    disabledControls[disabledControls.length] = radioArray[i];
    radioArray[i].disabled = true;
    if (radioArray[i].checked) {
      reqStr += (radioArray[i].name.match(/\d+/)+"-"+radioArray[i].value+",");
    }
  }

  if (reqStr.length > 1) {
    reqStr = reqStr.substr(reqStr, reqStr.length - 1);
  }

  makeRequest('cmd_command=image&cmd_action=get_url&products_id=' + products_id + '&attributes='+ reqStr, true);
}

function checkAttributesSelection()
{
  not_selected = false;

  tableElement = document.getElementById("optionsTable");
  selectArray = tableElement.getElementsByTagName("select");
  if (selectArray) {
    for (i = 0; i < selectArray.length; i++) {
      if (selectArray[i].value == -1) {
        not_selected = true;
	break;
      }
    }
  } else {
    tableElement = document.getElementById("optionsTable");
    radioArray = tableElement.getElementsByTagName("input");

    if (radioArray) {
      for (i = 0; i < radioArray.length; i++) {
        if (radioArray[i].value == -1) {
          not_selected = true;
	  break;
        }
      }
    }
  }

  if (not_selected) {
    alert(selection_alert);
    return false;
  } else {
    return true;
  }
}