var sendReq = getXmlHttpRequestObject();
var receiveReq = getXmlHttpRequestObject();
var uzytkownik = getXmlHttpRequestObject();
var lastMessage = 0;
var lastUser = 0;
var mTimer;
var uTimer;
var ch=0;
//Function for initializating the page.
function startChat(chat) {
	//Set the focus to the Message Box.
	ch=chat;
	document.getElementById('txt_message').focus();
	getChatUser(ch);
	getChatText(ch);
	}
	
//Gets the browser specific XmlHttpRequest Object
function getXmlHttpRequestObject() {
	if (window.XMLHttpRequest) {
		return new XMLHttpRequest();
	} else if(window.ActiveXObject) {
		return new ActiveXObject("Microsoft.XMLHTTP");
	} else {
		document.getElementById('p_status').innerHTML = 'Status: Cound not create XmlHttpRequest Object.  Consider upgrading your browser.';
	}
}
			
//Gets the current messages from the server
function getChatText(chat) {
	ch=chat;
	if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
		receiveReq.open("GET", './dzialy/chat/getChat.php?chat='+ch+'&last=' + lastMessage, true);
		receiveReq.onreadystatechange = handleReceiveChat; 
		receiveReq.send(null);
	}			
}

function getChatUser(ch){
	if (uzytkownik.readyState == 4 || uzytkownik.readyState == 0) {
		uzytkownik.open("POST", './dzialy/chat/getUser.php?chat='+ch+'&last=' + lastMessage + '&action=sprawdz_user' + '&user_nazwa=' + document.getElementById('user_nazwa').value + '&id_dzial=' + ch, true);
		uzytkownik.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
		uzytkownik.onreadystatechange = handleReceiveUser; 
		uzytkownik.send(null);
	}
}


function sendChatText() {
	if(document.getElementById('txt_message').value == '') {
		alert("You have not entered a message");
		return;
	}
	if (sendReq.readyState == 4 || sendReq.readyState == 0) {
		sendReq.open("POST", './dzialy/chat/getChat.php?chat='+ch+'&last=' + lastMessage, true);
		sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
		sendReq.onreadystatechange = handleSendChat; 
		var param = 'message=' + document.getElementById('txt_message').value;
		param += '&name=' + document.getElementById('user_nazwa').value;
		param += '&chat='+ch;
		sendReq.send(param);
		document.getElementById('txt_message').value = '';
	}							
}



function handleSendChat() {
	//Clear out the existing timer so we don't have 
	//multiple timer instances running.
	clearInterval(mTimer);
	getChatText(ch);
	getChatUser(ch);
}
//Function for handling the return of chat text
function handleReceiveChat() {
	if (receiveReq.readyState == 4) {
		var chat_div = document.getElementById('div_chat');
		var xmldoc = receiveReq.responseXML;
		var message_nodes = xmldoc.getElementsByTagName("message"); 
		var n_messages = message_nodes.length
		for (i = 0; i < n_messages; i++) {
			var user_node = message_nodes[i].getElementsByTagName("user");
			var text_node = message_nodes[i].getElementsByTagName("text");
			var time_node = message_nodes[i].getElementsByTagName("time");
			var kolor1_node=message_nodes[i].getElementsByTagName("colo");
			var kolor1=kolor1_node[0].firstChild.nodeValue;
			chat_div.innerHTML += '<div style="display: inline; color:'+kolor1+'">'+user_node[0].firstChild.nodeValue + '&nbsp;</div>';
			chat_div.innerHTML += '<div style="display: inline; color:'+kolor1+'" class="chat_time">' + time_node[0].firstChild.nodeValue + '</div>'
			chat_div.innerHTML += '<div style="color:'+kolor1+'">' +text_node[0].firstChild.nodeValue + '</div>';
			chat_div.scrollTop = chat_div.scrollHeight;
			lastMessage = (message_nodes[i].getAttribute('id'));
			}
		mTimer = setTimeout('getChatText(ch);',2000); //Refresh our chat in 2 seconds
	}
}

function handleReceiveUser(){
//TA - wyswietlanie listy urzytkowników
	if (uzytkownik.readyState == 4) {
		var xmldoc = uzytkownik.responseXML;
		var user_div = document.getElementById('div_user');
		var user_nodes = xmldoc.getElementsByTagName("usr"); 
		var n_user = user_nodes.length;
		user_div.innerHTML="";
		for (i = 0; i < n_user; i++) {
			var usr_node = user_nodes[i].getElementsByTagName("nazwa");
			var kolor2_node=user_nodes[i].getElementsByTagName("colo");
			var kolor2=kolor2_node[0].firstChild.nodeValue;
			user_div.innerHTML += '<table><tr><td style="color:'+kolor2+'">'+usr_node[0].firstChild.nodeValue + '</td></tr></table>';
			user_div.scrollTop = user_div.scrollHeight;
			//lastUser = (user_nodes[i].getAttribute('id'));
		}
	uTimer = setTimeout('getChatUser(ch);',50000);
	}
}

//This functions handles when the user presses enter.  Instead of submitting the form, we
//send a new message to the server and return false.
function blockSubmit(chat) {
	ch=chat;
	sendChatText(chat);
	return false;
	}
//This cleans out the database so we can start a new chat session.
function resetChat() {
	if (sendReq.readyState == 4 || sendReq.readyState == 0) {
		sendReq.open("POST", './dzialy/chat/getChat.php?chat='+ch+'&last=' + lastMessage, true);
		sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
		sendReq.onreadystatechange = handleResetChat; 
		var param = 'action=reset';
		sendReq.send(param);
		document.getElementById('txt_message').value = '';
	}							
}
//This function handles the response after the page has been refreshed.
function handleResetChat() {
	document.getElementById('div_chat').innerHTML = '';
	getChatText(ch);
	getChatUser(ch);
}