/lenasys/trunk

<?php

	Class User extends CI_Model {

		/*

		 *	Constructor

		 */

		function __construct() {

			parent::__construct();

			//Load required libraries

			$this->load->database();

			$this->load->library('session');

		}

		//Queries the DB and for a matching username and password. Returns result or false.

		/*

		 *	Constructor

		 */ 

		public function login($username, $password)

		{			

			//Generate a salted hash

			$hash = $this->getSaltedHash($password);

			//Query-structure

			$this->db->select('userName, name, passwd, userType, ssn');

			$this->db->from('Users');

			$this->db->where('userName', $username);

			$this->db->where('passwd', $hash);

			$this->db->limit(1);

			//Execute query

			$query = $this->db->get();

			$result = $query->result();

			//If a matching DB record is found.

			if($result) {

				//Prepare session data

				$userDetails = array();

				foreach($result as $row) {

					$userDetails = array(

						'username' => $row->userName,

						'name' => $row->name,

						'usertype' => $row->userType,

						'ssn' => $row->ssn

					);

				}

				//Set session data

				$this->session->set_userdata('authenticated', $userDetails);

				//Return success

				return TRUE;

			} else {

				//Return fail

				return FALSE;

			}	

		}

		/*

		 *	This function logs the user out.

		 */ 

		public function logout() {		

			//Unset session data

			$this->session->unset_userdata('authenticated');

		}

		/*

		 *	This function return TRUE if the user is logged in and FALSE otherwise.

		 */ 

		public function isLoggedIn() {	

			if ($this->session->userdata('authenticated')) {

				return TRUE;

			} else {

				return FALSE;

			}

		}

		//Generates a password hash using a user-unique salt.

		private function getSaltedHash($pwd)

		{	

			/* Salt algorithm:

			 * Step 1: Get encryption key

			 * Step 2: Salt is set to password (reversed)

			 * Step 3: Salt is encrypted with MD5

			 * Step 4: Salt is reversed (again)

			 * Step 5: Salt is encrypted with SHA1

			 */

			$salt = '';

			//UNCOMMENT TO ACTIVATE SALT LATER IN DEVELOPMENT!!!

			//$salt = sha1(strrev(md5(strrev($this->config->item('encryption_key')))));

			//Generate SHA1 hash using salt

			$hash = sha1($salt.$pwd);

			return $hash;

		}

	}

?>