<?php
class Current_User {

    /** Returns the User object for the logged in user. */
    private static $user;

    private function __construct() {}

    public static function user() {

        if(!isset(self::$user)) {
            // we use the $CI object to load the session library because this is a static class.
            $CI =& get_instance();

            if (!$user_id = $CI->session->userdata('user_id')) {
                return FALSE;
            }

            if (!$u = Doctrine::getTable('User')->find($user_id)) {
                return FALSE;
            }

            self::$user = $u;
        }

        return self::$user;
    }

    public static function login($username, $password) {

        // get User object by username
        if ($u = Doctrine::getTable('User')->findOneByUsername($username)) {

            // this mutates (encrypts) the input password
            $u_input = new User();
            $u_input->password = $password;

            // password match (comparing encrypted passwords)
            if ($u->password == $u_input->password) {
                unset($u_input);

                $CI =& get_instance();
                $CI->load->library('session');
                $CI->session->set_userdata('user_id',$u->id);
                self::$user = $u;

                return TRUE;
            }

            unset($u_input);
        }

        // login failed
        return FALSE;

    }

    public function __clone() {
        trigger_error('Clone is not allowed.', E_USER_ERROR);
    }

}