<?php
/**
 * @author Bernhard Posselt <dev@bernhard-posselt.com>
 * @author Lukas Reschke <lukas@owncloud.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Scrutinizer Auto-Fixer <auto-fixer@scrutinizer-ci.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Thomas Tanghus <thomas@tanghus.net>
 *
 * @copyright Copyright (c) 2015, ownCloud, Inc.
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */


namespace OC\AppFramework\Middleware\Security;

use OC\AppFramework\Http;
use OC\AppFramework\Utility\ControllerMethodReflector;
use OCP\AppFramework\Http\RedirectResponse;
use OCP\AppFramework\Middleware;
use OCP\AppFramework\Http\Response;
use OCP\AppFramework\Http\JSONResponse;
use OCP\INavigationManager;
use OCP\IURLGenerator;
use OCP\IRequest;
use OCP\ILogger;
use OCP\AppFramework\Controller;
use OCP\Util;


/**
 * Used to do all the authentication and checking stuff for a controller method
 * It reads out the annotations of a controller method and checks which if
 * security things should be checked and also handles errors in case a security
 * check fails
 */
class SecurityMiddleware extends Middleware {

	private $navigationManager;
	private $request;
	private $reflector;
	private $appName;
	private $urlGenerator;
	private $logger;
	private $isLoggedIn;
	private $isAdminUser;

	/**
	 * @param IRequest $request
	 * @param ControllerMethodReflector $reflector
	 * @param INavigationManager $navigationManager
	 * @param IURLGenerator $urlGenerator
	 * @param ILogger $logger
	 * @param string $appName
	 * @param bool $isLoggedIn
	 * @param bool $isAdminUser
	 */
	public function __construct(IRequest $request,
								ControllerMethodReflector $reflector,
								INavigationManager $navigationManager,
								IURLGenerator $urlGenerator,
								ILogger $logger,
								$appName,
								$isLoggedIn,
								$isAdminUser){
		$this->navigationManager = $navigationManager;
		$this->request = $request;
		$this->reflector = $reflector;
		$this->appName = $appName;
		$this->urlGenerator = $urlGenerator;
		$this->logger = $logger;
		$this->isLoggedIn = $isLoggedIn;
		$this->isAdminUser = $isAdminUser;
	}


	/**
	 * This runs all the security checks before a method call. The
	 * security checks are determined by inspecting the controller method
	 * annotations
	 * @param string $controller the controllername or string
	 * @param string $methodName the name of the method
	 * @throws SecurityException when a security check fails
	 */
	public function beforeController($controller, $methodName){

		// this will set the current navigation entry of the app, use this only
		// for normal HTML requests and not for AJAX requests
		$this->navigationManager->setActiveEntry($this->appName);

		// security checks
		$isPublicPage = $this->reflector->hasAnnotation('PublicPage');
		if(!$isPublicPage) {
			if(!$this->isLoggedIn) {
				throw new SecurityException('Current user is not logged in', Http::STATUS_UNAUTHORIZED);
			}

			if(!$this->reflector->hasAnnotation('NoAdminRequired')) {
				if(!$this->isAdminUser) {
					throw new SecurityException('Logged in user must be an admin', Http::STATUS_FORBIDDEN);
				}
			}
		}

		// CSRF check - also registers the CSRF token since the session may be closed later
		Util::callRegister();
		if(!$this->reflector->hasAnnotation('NoCSRFRequired')) {
			if(!$this->request->passesCSRFCheck()) {
				throw new SecurityException('CSRF check failed', Http::STATUS_PRECONDITION_FAILED);
			}
		}

		/**
		 * FIXME: Use DI once available
		 * Checks if app is enabled (also inclues a check whether user is allowed to access the resource)
		 * The getAppPath() check is here since components such as settings also use the AppFramework and
		 * therefore won't pass this check.
		 */
		if(\OC_App::getAppPath($this->appName) !== false && !\OC_App::isEnabled($this->appName)) {
			throw new SecurityException('App is not enabled', Http::STATUS_PRECONDITION_FAILED);
		}

	}


	/**
	 * If an SecurityException is being caught, ajax requests return a JSON error
	 * response and non ajax requests redirect to the index
	 * @param Controller $controller the controller that is being called
	 * @param string $methodName the name of the method that will be called on
	 *                           the controller
	 * @param \Exception $exception the thrown exception
	 * @throws \Exception the passed in exception if it cant handle it
	 * @return Response a Response object or null in case that the exception could not be handled
	 */
	public function afterException($controller, $methodName, \Exception $exception){
		if($exception instanceof SecurityException){

			if (stripos($this->request->getHeader('Accept'),'html')===false) {

				$response = new JSONResponse(
					array('message' => $exception->getMessage()),
					$exception->getCode()
				);
				$this->logger->debug($exception->getMessage());
			} else {

				// TODO: replace with link to route
				$url = $this->urlGenerator->getAbsoluteURL('index.php');
				// add redirect URL to redirect to the previous page after login
				$url .= '?redirect_url=' . urlencode($this->request->server['REQUEST_URI']);
				$response = new RedirectResponse($url);
				$this->logger->debug($exception->getMessage());
			}

			return $response;

		}

		throw $exception;
	}

}
