<?php
/**
 * @copyright Copyright (c) 2015, ownCloud, Inc.
 *
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 *
 * @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 OCA\Files_External\Lib\Auth\Password;

use OCA\Files_External\Lib\Auth\AuthMechanism;
use OCA\Files_External\Lib\InsufficientDataForMeaningfulAnswerException;
use OCA\Files_External\Lib\StorageConfig;
use OCP\Authentication\Exceptions\CredentialsUnavailableException;
use OCP\Authentication\LoginCredentials\IStore as CredentialsStore;
use OCP\EventDispatcher\IEventDispatcher;
use OCP\IL10N;
use OCP\ISession;
use OCP\IUser;
use OCP\Security\ICredentialsManager;
use OCP\User\Events\PasswordUpdatedEvent;
use OCP\User\Events\UserLoggedInEvent;

/**
 * Username and password from login credentials, saved in DB
 */
class LoginCredentials extends AuthMechanism {
	public const CREDENTIALS_IDENTIFIER = 'password::logincredentials/credentials';

	/** @var ISession */
	protected $session;

	/** @var ICredentialsManager */
	protected $credentialsManager;

	/** @var CredentialsStore */
	private $credentialsStore;

	public function __construct(IL10N $l, ISession $session, ICredentialsManager $credentialsManager, CredentialsStore $credentialsStore, IEventDispatcher $eventDispatcher) {
		$this->session = $session;
		$this->credentialsManager = $credentialsManager;
		$this->credentialsStore = $credentialsStore;

		$this
			->setIdentifier('password::logincredentials')
			->setScheme(self::SCHEME_PASSWORD)
			->setText($l->t('Log-in credentials, save in database'))
			->addParameters([
			]);

		$eventDispatcher->addListener(UserLoggedInEvent::class, [$this, 'updateCredentials']);
		$eventDispatcher->addListener(PasswordUpdatedEvent::class, [$this, 'updateCredentials']);
	}

	/**
	 * @param UserLoggedInEvent | PasswordUpdatedEvent $event
	 */
	public function updateCredentials($event) {
		if ($event instanceof UserLoggedInEvent && $event->isTokenLogin()) {
			return;
		}

		$stored = $this->credentialsManager->retrieve($event->getUser()->getUID(), self::CREDENTIALS_IDENTIFIER);

		if ($stored && $stored['password'] != $event->getPassword()) {
			$credentials = [
				'user' => $stored['user'],
				'password' => $event->getPassword()
			];

			$this->credentialsManager->store($event->getUser()->getUID(), self::CREDENTIALS_IDENTIFIER, $credentials);
		}
	}

	private function getCredentials(IUser $user): array {
		$credentials = $this->credentialsManager->retrieve($user->getUID(), self::CREDENTIALS_IDENTIFIER);

		if (is_null($credentials)) {
			// nothing saved in db, try to get it from the session and save it
			try {
				$sessionCredentials = $this->credentialsStore->getLoginCredentials();

				$credentials = [
					'user' => $sessionCredentials->getLoginName(),
					'password' => $sessionCredentials->getPassword()
				];

				$this->credentialsManager->store($user->getUID(), self::CREDENTIALS_IDENTIFIER, $credentials);
			} catch (CredentialsUnavailableException $e) {
				throw new InsufficientDataForMeaningfulAnswerException('No login credentials saved');
			}
		}

		return $credentials;
	}

	public function manipulateStorageConfig(StorageConfig &$storage, IUser $user = null) {
		if (!isset($user)) {
			throw new InsufficientDataForMeaningfulAnswerException('No login credentials saved');
		}
		$credentials = $this->getCredentials($user);

		$storage->setBackendOption('user', $credentials['user']);
		$storage->setBackendOption('password', $credentials['password']);
	}
}