<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Bart Visscher <bartv@thisnet.nl>
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Jörn Friedrich Dreyer <jfd@butonic.de>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <robin@icewind.nl>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Roger Szabo <roger.szabo@web.de>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 *
 * @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\User_LDAP\Jobs;

use OC\BackgroundJob\TimedJob;
use OCA\User_LDAP\Group_Proxy;
use OCP\EventDispatcher\IEventDispatcher;
use OCP\Group\Events\UserAddedEvent;
use OCP\Group\Events\UserRemovedEvent;
use OCP\ILogger;

class UpdateGroups extends TimedJob {
	private $groupsFromDB;

	/** @var Group_Proxy */
	private $groupBackend;

	public function __construct(Group_Proxy $groupBackend) {
		$this->interval = $this->getRefreshInterval();
		$this->groupBackend = $groupBackend;
	}

	/**
	 * @param mixed $argument
	 */
	public function run($argument) {
		$this->updateGroups();
	}

	public function updateGroups() {
		\OCP\Util::writeLog('user_ldap', 'Run background job "updateGroups"', ILogger::DEBUG);

		$knownGroups = array_keys($this->getKnownGroups());
		$actualGroups = $this->groupBackend->getGroups();

		if (empty($actualGroups) && empty($knownGroups)) {
			\OCP\Util::writeLog('user_ldap',
				'bgJ "updateGroups" – groups do not seem to be configured properly, aborting.',
				ILogger::INFO);
			return;
		}

		$this->handleKnownGroups(array_intersect($actualGroups, $knownGroups));
		$this->handleCreatedGroups(array_diff($actualGroups, $knownGroups));
		$this->handleRemovedGroups(array_diff($knownGroups, $actualGroups));

		\OCP\Util::writeLog('user_ldap', 'bgJ "updateGroups" – Finished.', ILogger::DEBUG);
	}

	/**
	 * @return int
	 */
	private function getRefreshInterval() {
		//defaults to every hour
		return \OC::$server->getConfig()->getAppValue('user_ldap', 'bgjRefreshInterval', 3600);
	}

	/**
	 * @param string[] $groups
	 */
	private function handleKnownGroups($groups) {
		/** @var IEventDispatcher $dispatcher */
		$dispatcher = \OC::$server->query(IEventDispatcher::class);
		$groupManager = \OC::$server->getGroupManager();
		$userManager = \OC::$server->getUserManager();

		\OCP\Util::writeLog('user_ldap', 'bgJ "updateGroups" – Dealing with known Groups.', ILogger::DEBUG);
		$query = \OC_DB::prepare('
			UPDATE `*PREFIX*ldap_group_members`
			SET `owncloudusers` = ?
			WHERE `owncloudname` = ?
		');
		if (!is_array($this->groupsFromDB)) {
			$this->getKnownGroups();
		}
		foreach ($groups as $group) {
			$knownUsers = unserialize($this->groupsFromDB[$group]['owncloudusers']);
			$actualUsers = $this->groupBackend->usersInGroup($group);
			$hasChanged = false;

			$groupObject = $groupManager->get($group);
			foreach (array_diff($knownUsers, $actualUsers) as $removedUser) {
				$userObject = $userManager->get($removedUser);
				$dispatcher->dispatchTyped(new UserRemovedEvent($groupObject, $userObject));
				\OCP\Util::writeLog('user_ldap',
				'bgJ "updateGroups" – "'.$removedUser.'" removed from "'.$group.'".',
					ILogger::INFO);
				$hasChanged = true;
			}
			foreach (array_diff($actualUsers, $knownUsers) as $addedUser) {
				$userObject = $userManager->get($addedUser);
				$dispatcher->dispatchTyped(new UserAddedEvent($groupObject, $userObject));
				\OCP\Util::writeLog('user_ldap',
				'bgJ "updateGroups" – "'.$addedUser.'" added to "'.$group.'".',
					ILogger::INFO);
				$hasChanged = true;
			}
			if ($hasChanged) {
				$query->execute([serialize($actualUsers), $group]);
			}
		}
		\OCP\Util::writeLog('user_ldap',
			'bgJ "updateGroups" – FINISHED dealing with known Groups.',
			ILogger::DEBUG);
	}

	/**
	 * @param string[] $createdGroups
	 */
	private function handleCreatedGroups($createdGroups) {
		\OCP\Util::writeLog('user_ldap', 'bgJ "updateGroups" – dealing with created Groups.', ILogger::DEBUG);
		$query = \OC_DB::prepare('
			INSERT
			INTO `*PREFIX*ldap_group_members` (`owncloudname`, `owncloudusers`)
			VALUES (?, ?)
		');
		foreach ($createdGroups as $createdGroup) {
			\OCP\Util::writeLog('user_ldap',
				'bgJ "updateGroups" – new group "'.$createdGroup.'" found.',
				ILogger::INFO);
			$users = serialize($this->groupBackend->usersInGroup($createdGroup));
			$query->execute([$createdGroup, $users]);
		}
		\OCP\Util::writeLog('user_ldap',
			'bgJ "updateGroups" – FINISHED dealing with created Groups.',
			ILogger::DEBUG);
	}

	/**
	 * @param string[] $removedGroups
	 */
	private function handleRemovedGroups($removedGroups) {
		\OCP\Util::writeLog('user_ldap', 'bgJ "updateGroups" – dealing with removed groups.', ILogger::DEBUG);
		$query = \OC_DB::prepare('
			DELETE
			FROM `*PREFIX*ldap_group_members`
			WHERE `owncloudname` = ?
		');
		foreach ($removedGroups as $removedGroup) {
			\OCP\Util::writeLog('user_ldap',
				'bgJ "updateGroups" – group "'.$removedGroup.'" was removed.',
				ILogger::INFO);
			$query->execute([$removedGroup]);
		}
		\OCP\Util::writeLog('user_ldap',
			'bgJ "updateGroups" – FINISHED dealing with removed groups.',
			ILogger::DEBUG);
	}

	/**
	 * @return array
	 */
	private function getKnownGroups() {
		if (is_array($this->groupsFromDB)) {
			$this->groupsFromDB;
		}
		$query = \OC_DB::prepare('
			SELECT `owncloudname`, `owncloudusers`
			FROM `*PREFIX*ldap_group_members`
		');
		$result = $query->execute()->fetchAll();
		$this->groupsFromDB = [];
		foreach ($result as $dataset) {
			$this->groupsFromDB[$dataset['owncloudname']] = $dataset;
		}

		return $this->groupsFromDB;
	}
}