<?php

/**
 * EXHIBIT A. Common Public Attribution License Version 1.0
 * The contents of this file are subject to the Common Public Attribution License Version 1.0 (the “License”);
 * you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.oxwall.org/license. The License is based on the Mozilla Public License Version 1.1
 * but Sections 14 and 15 have been added to cover use of software over a computer network and provide for
 * limited attribution for the Original Developer. In addition, Exhibit A has been modified to be consistent
 * with Exhibit B. Software distributed under the License is distributed on an “AS IS” basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language
 * governing rights and limitations under the License. The Original Code is Oxwall software.
 * The Initial Developer of the Original Code is Oxwall Foundation (http://www.oxwall.org/foundation).
 * All portions of the code written by Oxwall Foundation are Copyright (c) 2011. All Rights Reserved.

 * EXHIBIT B. Attribution Information
 * Attribution Copyright Notice: Copyright 2011 Oxwall Foundation. All rights reserved.
 * Attribution Phrase (not exceeding 10 words): Powered by Oxwall community software
 * Attribution URL: http://www.oxwall.org/
 * Graphic Image as provided in the Covered Code.
 * Display of Attribution Information is required in Larger Works which are defined in the CPAL as a work
 * which combines Covered Code or portions thereof with code not governed by the terms of the CPAL.
 */

/**
 * The class is a gateway for auth. adapters and provides common API to authenticate users.
 *
 * @author Sardar Madumarov <madumarov@gmail.com>
 * @package ow_core
 * @since 1.0
 */
class OW_Auth
{
    /**
     * @var OW_IAuthenticator
     */
    private $authenticator;
    /**
     * Singleton instance.
     *
     * @var OW_Auth
     */
    private static $classInstance;

    /**
     * Returns an instance of class (singleton pattern implementation).
     *
     * @return OW_Auth
     */
    public static function getInstance()
    {
        if ( self::$classInstance === null )
        {
            self::$classInstance = new self();
        }

        return self::$classInstance;
    }

    /**
     * Constructor.
     */
    private function __construct()
    {

    }

    /**
     * @return OW_IAuthenticator
     */
    public function getAuthenticator()
    {
        return $this->authenticator;
    }

    /**
     * @param OW_IAuthenticator $authenticator
     */
    public function setAuthenticator( OW_IAuthenticator $authenticator )
    {
        $this->authenticator = $authenticator;
    }

    /**
     * Tries to authenticate user using provided adapter.
     *
     * @param OW_AuthAdapter $adapter
     * @return OW_AuthResult
     */
    public function authenticate( OW_AuthAdapter $adapter )
    {
        $result = $adapter->authenticate();

        if ( !( $result instanceof OW_AuthResult ) )
        {
            throw new LogicException('Instance of OW_AuthResult expected!');
        }

        if ( $result->isValid() )
        {
            $this->login($result->getUserId());
        }

        return $result;
    }

    /**
     * Checks if current user is authenticated.
     *
     * @return boolean
     */
    public function isAuthenticated()
    {
        return $this->authenticator->isAuthenticated();
    }

    /**
     * Returns current user id.
     * If user is not authenticated 0 returned.
     *
     * @return integer
     */
    public function getUserId()
    {
        return $this->authenticator->getUserId();
    }

    /**
     * Logins user by provided user id.
     *
     * @param integer $userId
     * @return string
     */
    public function login( $userId )
    {
        $userId = (int) $userId;

        if ( $userId < 1 )
        {
            throw new InvalidArgumentException('invalid userId');
        }

        $event = new OW_Event(OW_EventManager::ON_BEFORE_USER_LOGIN, array('userId' => $userId));
        OW::getEventManager()->trigger($event);

        $this->authenticator->login($userId);

        $event = new OW_Event(OW_EventManager::ON_USER_LOGIN, array('userId' => $userId));
        OW::getEventManager()->trigger($event);
    }

    /**
     * Logs out current user.
     */
    public function logout()
    {
        if ( !$this->isAuthenticated() )
        {
            return;
        }

        $event = new OW_Event(OW_EventManager::ON_USER_LOGOUT, array('userId' => $this->getUserId()));
        OW::getEventManager()->trigger($event);

        $this->authenticator->logout();
    }

    /**
     * Returns auth id
     *
     * @return string
     */
    public function getId()
    {
        return $this->authenticator->getId();
    }
}