// js handling the login procedures

// constants
var NORMAL_STATE = 4;
var LOGIN_PREFIX = 'http://' + location.host + '/download_area/login.asp?';

// variables
var http = getHTTPObject(); // We create the HTTP Object
var hasSeed = false;
var loggedIn = false;
var seed_id = 0;
var seed = 0;
var fullname = '';
var messages = '';


function getHTTPObject() {

	var xhr = false;//set to false, so if it fails, do nothing
	if(window.XMLHttpRequest) {//detect to see if browser allows this method
		var xhr = new XMLHttpRequest();//set var the new request
	} else if(window.ActiveXObject) {//detect to see if browser allows this method
		try {
			var xhr = new ActiveXObject("Msxml2.XMLHTTP");//try this method first
		} catch(e) {//if it fails move onto the next
			try {
				var xhr = new ActiveXObject("Microsoft.XMLHTTP");//try this method next
			} catch(e) {//if that also fails return false.
			xhr = false;
			}
		}
	}
	return xhr;//return the value of xhr
}

// getSeed method:  gets a seed from the server for this transaction
function getSeed() 
{		// only get a seed if we're not logged in and we don't already have one
		if (!loggedIn && !hasSeed) {
			// open up the path
			http.open('GET', LOGIN_PREFIX + 'task=getseed', true);
			http.onreadystatechange = handleHttpGetSeed;
			http.send(null);
		}
}

// handleHttpGetSeed method: called when the seed is returned from the server
function handleHttpGetSeed()
{

	// if there hasn't been any errors
	if (http.readyState == NORMAL_STATE) {
		// split by the divider |
		results = http.responseText.split('|');
		// id is the first element
		seed_id = results[0];
		
		//alert("getting seed: " + seed_id);
		// seed is the second element
		seed = results[1];
		
		// now we have the seed
		hasSeed = true;
	}
}

// validateLogin method: validates a login request
function validateLogin()
{
	// ignore request if we are already logged in
	if (loggedIn){
		return;
	}
	// get form form elements 'username' and 'password'
	username = document.getElementById('username').value;
	password = document.getElementById('password').value;
	document.getElementById('setcookie').checked?cookie = 1:cookie=0;
	
	// ignore if either is empty
	if (username != '' && password  != '') {
	
		// compute the hash of the hash of the password and the seed
		hash = SHA1(SHA1(password) + seed);
		// open the http connection
		//alert('task=checklogin&username='+username+'&id='+seed_id+'&hash='+hash+'&cookie='+cookie);
		http.open('GET', LOGIN_PREFIX + 'task=checklogin&username='+username+'&id='+seed_id+'&hash='+hash+'&cookie='+cookie, true);
		
		// where to go
		http.onreadystatechange = handleHttpValidateLogin;
		http.send(null);
	}else{
		//alert("empty");
	}
}

// handleHttpValidateLogin method: called when the validation results are returned from the server
function handleHttpValidateLogin()
{
	// did the connection work?
	if (http.readyState == NORMAL_STATE) {
		// split by the pipe
		results = http.responseText.split('|');
		if (results[0] == 'true')
		{
			hasSeed = false;
			loggedIn = true;
			fullname = results[1];
			firstname = results[2];
			surname = results[3];
			sex = results[4];
			messages = '';
			/*if(document.getElementById('setcookie').checked){
				setCookie('loggedIn','true',365);
				setCookie('userName',results[1],365);
			}*/
		}
		else
		{
			messages = results[1];
		}
		showLogin();
	}
}


/*************** COOKIES **************/
function setCookie(c_name,value,expiredays){
	var exdate=new Date();
	exdate.setDate(exdate.getDate()+expiredays);
	
	document.cookie=c_name+ "=" +escape(value)+
	((expiredays==null) ? "" : ";expires="+exdate.toGMTString())+
	"; path=/";
}

function deleteCookie() {
		
	if(getCookie('loggedIn') == 'true'){
		document.cookie='loggedIn=' +escape('false')+
		';expires=Thu, 01-Jan-1970 00:00:01 GMT';
	}
		
}

function checkLoggedIn(){
	lIn = getCookie('loggedIn');
	if(lIn=='true'){
		loggedIn = true;
	}
}

function checkUser(){
	username=getCookie('username');
}


function getCookie(c_name){
	if (document.cookie.length>0){
	  c_start=document.cookie.indexOf(c_name + "=");
	  if (c_start!=-1)
		{ 
		c_start=c_start + c_name.length+1; 
		c_end=document.cookie.indexOf(";",c_start);
		if (c_end==-1) c_end=document.cookie.length;
		return unescape(document.cookie.substring(c_start,c_end));
		} 
	  }
	return "";
}
/*********************************************/


// resetLogin method: if logged in, 'logs out' and allows a different user/pass to be entered
function resetLogin()
{
	loggedIn = false;
	hasSeed = false;
}