/* chatURL - URL for updating chat messages */
var chatURL = "./chat.php";
/* create XMLHttpRequest objects for updating the chat messages and getting the selected color */
var xmlHttpGetMessages = createXmlHttpRequestObject();
/* variables that establish how often to access the server */
var updateInterval = 5000; // how many miliseconds to wait to get new message
// when set to true, display detailed error messages
var debugMode = true;
/* initialize the messages cache */
var cache = new Array();
/* lastMessageID - the ID of the most recent chat message */
var lastMessageID = -1; 
/* global slot to store old name */
var oldUser = "";
 /* global slot to store current name */
var curUser = "";
 /* global slot to store current name */
var muteList = 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 prog 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) {}
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
    alert("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}

/* this function initiates the chat; it executes when the chat page loads */
function init() 
{
  // get a reference to the text box where the user writes new messages
  var oMessageBox = document.getElementById("messageBox");
  // prevents the autofill function from starting
  oMessageBox.setAttribute("autocomplete", "off");    
  // ensures our user has a default random name when the form loads
  checkUsername('init1');
  // initiates updating the chat window
  document.getElementById("messageBox").value="/msg " + curUser + " Welcome to SR5 Chat! Type /help for more info";
  sendMessage('admin');

  requestNewMessages();
}

// function that ensures that the username is never empty and if so 
// a random name is generated
function checkUsername(fstate)
{
  // ensures our user has a default random name when the form loads
  var oUser=document.getElementById("userName");

if ((oUser.value == "") && (fstate == 'init1')) {
  oUser.value = "Lurker" + Math.floor(Math.random() * 100);
curUser=oUser.value;
  document.getElementById("messageBox").value= oUser.value + " has joined.";
  sendMessage('admin');
}
if (fstate == 'in') { oldUser = oUser.value; oUser.value="";}

if ((fstate == 'out') && (oUser.value == "")) oUser.value=oldUser;
if ((fstate == 'out') && (oUser.value == "SR5")) oUser.value=oldUser;
if ((fstate == 'out') && (oldUser != oUser.value)) {

  document.getElementById("messageBox").value= oldUser+" has become "+oUser.value;
  sendMessage('admin');
  curUser = oUser.value;
}
}
 
/* function called when the Send button is pressed */
function sendMessage(fstate)
{
  // save the message to a local variable and clear the text box
  var oCurrentMessage = document.getElementById("messageBox");
  var currentUser = document.getElementById("userName").value;
if (fstate == 'admin') currentUser = "SR5";
  // don't send void messages
  if (trim(oCurrentMessage.value) != "" &&
      trim(currentUser) != "")
  {
    // if we need to send and retrieve messages
    params =  "mode=SendAndRetrieveNew" +
              "&id=" + encodeURIComponent(lastMessageID) + 
              "&name=" + encodeURIComponent(currentUser) + 
              "&message=" + encodeURIComponent(oCurrentMessage.value);
    // add the message to the queue
    cache.push(params);
    // clear the text box
    oCurrentMessage.value = "";
  }
}

/* function called when the page closes */
function closeChat()
{

var params = "";
params =  "mode=SendAndRetrieveNew" +
              "&id=" + encodeURIComponent(lastMessageID) + 
              "&name=" + encodeURIComponent("SR5") + 
              "&message=" + encodeURIComponent(curUser + " has left 4run.");
        xmlHttpGetMessages.open("POST", chatURL, true);
        xmlHttpGetMessages.setRequestHeader("Content-Type", 
                                   "application/x-www-form-urlencoded");

        xmlHttpGetMessages.send(params);
}

/* function called when the Delete Messages button is pressed */
function deleteMessages()
{
  // set the flag that specifies we're deleting the messages
  params = "mode=DeleteAndRetrieveNew";  
  // add the message to the queue
  cache.push(params);
}

/* makes asynchronous request to retrieve new messages, post new messages, delete messages */
function requestNewMessages()
{  
  // retrieve the username and color from the page
  var currentUser = document.getElementById("userName").value;
  // only continue if xmlHttpGetMessages isn't void
  if(xmlHttpGetMessages)
  {
    try
    {
      // don't start another server operation if such an operation 
      //   is already in progress 
      if (xmlHttpGetMessages.readyState == 4 || 
          xmlHttpGetMessages.readyState == 0) 
      {
        // we will store the parameters used to make the server request
        var params = "";
        // if there are requests stored in queue, take the oldest one
        if (cache.length>0)
          params = cache.shift();
        // if the cache is empty, just retrieve new messages        
        else
          params = "mode=RetrieveNew" +
                   "&id=" +lastMessageID;      
  // call the server page to execute the server-side operation
        xmlHttpGetMessages.open("POST", chatURL, true);
        xmlHttpGetMessages.setRequestHeader("Content-Type", 
                                   "application/x-www-form-urlencoded");
        xmlHttpGetMessages.onreadystatechange = handleReceivingMessages;
 
        xmlHttpGetMessages.send(params);
      }
      else
      {
        // we will check again for new messages 
        setTimeout("requestNewMessages();", updateInterval);
      }
    }
    catch(e)
    {
      displayError(e.toString());
    }
  }
}

/* function that handles the http response when updating messages */
function handleReceivingMessages() 
{
  // continue if the process is completed
  if (xmlHttpGetMessages.readyState == 4) 
  {
    // continue only if HTTP status is "OK"
    if (xmlHttpGetMessages.status == 200) 
    {
      try
      {
        // process the server's response
        readMessages();
      }
      catch(e)
      {
        // display the error message
        displayError(e.toString());
      }
    } 
    else
    {
      // display the error message
      displayError(xmlHttpGetMessages.statusText);
    }
  }
}

/* function that processes the server's response when updating messages */
function readMessages()
{  
  // retrieve the server's response 
  var response = xmlHttpGetMessages.responseText;
  // server error?
  if (response.indexOf("ERRNO") >= 0 
      || response.indexOf("error:") >= 0
      || response.length == 0)
    throw(response.length == 0 ? "Void server response." : response);
  // retrieve the document element
  response = xmlHttpGetMessages.responseXML.documentElement;
  // retrieve the flag that says if the chat window has been cleared or not 
  clearChat = 
           response.getElementsByTagName("clear").item(0).firstChild.data;
  // if the flag is set to true, we need to clear the chat window 
  if(clearChat == "true")
  {
    // clear chat window and reset the id
    document.getElementById("scroll").innerHTML = "";
    lastMessageID = -1;
}

  // retrieve the arrays from the server's response     
  idArray = response.getElementsByTagName("id");
  nameArray = response.getElementsByTagName("name");
  timeArray = response.getElementsByTagName("time");
  messageArray = response.getElementsByTagName("message");
  // add the new messages to the chat window
  displayMessages(idArray, nameArray, timeArray, 
                                                       messageArray);
  // the ID of the last received message is stored locally
  if(idArray.length>0)
    lastMessageID = idArray.item(idArray.length - 1).firstChild.data;
  // restart sequence
  setTimeout("requestNewMessages();", updateInterval);
}

/* function that appends the new messages to the chat list  */
function displayMessages(idArray, nameArray, 
                         timeArray, messageArray)
{
  // each loop adds a new message
for(var i=0; i<idArray.length; i++)
  {
    // get the message details
    var time = timeArray.item(i).firstChild.data.toString();
    var name = nameArray.item(i).firstChild.data.toString();
    var message = messageArray.item(i).firstChild.data.toString();
    var color = "#000000";
    var showmsg = "";
    // compose the HTML code that displays the message

if (name == 'SR5') color = "#FF0000";

if (message.charAt(0) == '/'){ 

var msgcase = message.split(" ");
message = message.replace(msgcase[0], "");
switch(msgcase[0]){ 
case "/msg":
color = "#0000FF";
var pname = msgcase[1];
message = message.replace(msgcase[1], "");
if (pname == document.getElementById("userName").value) showmsg = 1;
else showmsg = 0;
break
case "/mute":
message = msgcase[1] + " is muted";
color = "#FF0000";
if (name == document.getElementById("userName").value) muteList[muteList.length+1] = msgcase[1];
showmsg=0;
break
case "/help":
message="Click in the name box to change your screen name<br/>Type /msg name message to send a private message.<br/>Type /mute name to not see messages from that person.<br/>Type /help to see this note again.";
color = "#009900";
showmsg=0;
if (msgcase[1] == document.getElementById("userName").value) showmsg = 1;
break
default:
color = "#FF0000";
message = "Error: message not sent";
showmsg = 0;
}
}
else
showmsg = 1;

if (name == document.getElementById("userName").value) showmsg = 1;
for (var i=0; i < muteList.length; i++) if (name == muteList[i]) showmsg = 0;
    var htmlMessage = "";
    htmlMessage += "<div class=\"item\" style=\"color:" + color + "\">"; 
if (pname) htmlMessage += name + " says to " + pname + ": <br/>";
else
if ((color != "#009900") && (color != "#FF0000")) htmlMessage += name + " says: <br/>";
if (color == "#FF0000") htmlMessage += "SR5 says: <br/>";
    htmlMessage += message.toString();
    htmlMessage += "</div>";
    // display the message
    if (showmsg == 1) displayMessage (htmlMessage);
  }
}

// displays a message
function displayMessage(message)
{
  // get the scroll object
  var oScroll = document.getElementById("scroll");
  // check if the scroll is down
  var scrollDown = (oScroll.scrollHeight - oScroll.scrollTop <= 
                    oScroll.offsetHeight );
  // display the message
  oScroll.innerHTML += message;
  // scroll down the scrollbar
  oScroll.scrollTop = scrollDown ? oScroll.scrollHeight : oScroll.scrollTop;
}

// function that displays an error message
function displayError(message)
{
  // display error message, with more technical details if debugMode is true
  displayMessage("Error accessing the server! "+
                 (debugMode ? "<br/>" + message : ""));
}

/* removes leading and trailing spaces from the string */
function trim(s)
{
    return s.replace(/(^\s+)|(\s+$)/g, "")
}


function handleKey(e) 
{
  // get the event
  e = (!e) ? window.event : e;
  // get the code of the character that has been pressed        
  code = (e.charCode) ? e.charCode :
         ((e.keyCode) ? e.keyCode :
         ((e.which) ? e.which : 0));
  // handle the keydown event       
  if (e.type == "keydown") 
  {
    // if enter (code 13) is pressed
    if(code == 13)
    {
      // send the current message  
      sendMessage();
    }
  }
}