<?php
/**
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @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\Files\External\Service;

use OCP\Files\Config\IUserMountCache;
use OCP\IUserSession;
use OCP\IGroupManager;
use OCP\Files\External\IStorageConfig;
use OCP\Files\External\IStoragesBackendService;
use OCP\Files\External\Service\IUserGlobalStoragesService;
use OCP\Security\ICrypto;

/**
 * Service class to read global storages applicable to the user
 * Read-only access available, attempting to write will throw DomainException
 */
class UserGlobalStoragesService extends GlobalStoragesService implements IUserGlobalStoragesService {
	use UserTrait;

	/** @var IGroupManager */
	protected $groupManager;

	/**
	 * @param IStoragesBackendService $backendService
	 * @param DBConfigService $dbConfig
	 * @param IUserSession $userSession
	 * @param IGroupManager $groupManager
	 * @param IUserMountCache $userMountCache
	 */
	public function __construct(
		IStoragesBackendService $backendService,
		DBConfigService $dbConfig,
		IUserSession $userSession,
		IGroupManager $groupManager,
		IUserMountCache $userMountCache,
		ICrypto $crypto
	) {
		parent::__construct($backendService, $dbConfig, $userMountCache, $crypto);
		$this->userSession = $userSession;
		$this->groupManager = $groupManager;
	}

	/**
	 * Replace config hash ID with real IDs, for migrating legacy storages
	 *
	 * @param IStorageConfig[] $storages Storages with real IDs
	 * @param IStorageConfig[] $storagesWithConfigHash Storages with config hash IDs
	 */
	protected function setRealStorageIds(array &$storages, array $storagesWithConfigHash) {
		// as a read-only view, storage IDs don't need to be real
		foreach ($storagesWithConfigHash as $storage) {
			$storages[$storage->getId()] = $storage;
		}
	}

	protected function readDBConfig() {
		$userMounts = $this->dbConfig->getAdminMountsFor(DBConfigService::APPLICABLE_TYPE_USER, $this->getUser()->getUID());
		$globalMounts = $this->dbConfig->getAdminMountsFor(DBConfigService::APPLICABLE_TYPE_GLOBAL, null);
		$groups = $this->groupManager->getUserGroupIds($this->getUser());
		if (\is_array($groups) && \count($groups) !== 0) {
			$groupMounts = $this->dbConfig->getAdminMountsForMultiple(DBConfigService::APPLICABLE_TYPE_GROUP, $groups);
		} else {
			$groupMounts = [];
		}
		return \array_merge($userMounts, $groupMounts, $globalMounts);
	}

	public function addStorage(IStorageConfig $newStorage) {
		throw new \DomainException('UserGlobalStoragesService writing disallowed');
	}

	public function updateStorage(IStorageConfig $updatedStorage) {
		throw new \DomainException('UserGlobalStoragesService writing disallowed');
	}

	/**
	 * @param integer $id
	 */
	public function removeStorage($id) {
		throw new \DomainException('UserGlobalStoragesService writing disallowed');
	}

	/**
	 * Get unique storages, in case two are defined with the same mountpoint
	 * Higher priority storages take precedence
	 *
	 * @return IStorageConfig[]
	 */
	public function getUniqueStorages() {
		$storages = $this->getStorages();

		$storagesByMountpoint = [];
		foreach ($storages as $storage) {
			$storagesByMountpoint[$storage->getMountPoint()][] = $storage;
		}

		$result = [];
		foreach ($storagesByMountpoint as $storageList) {
			$storage = \array_reduce($storageList, function ($carry, $item) {
				if (isset($carry)) {
					$carryPriorityType = $this->getPriorityType($carry);
					$itemPriorityType = $this->getPriorityType($item);
					if ($carryPriorityType > $itemPriorityType) {
						return $carry;
					} elseif ($carryPriorityType === $itemPriorityType) {
						if ($carry->getPriority() > $item->getPriority()) {
							return $carry;
						}
					}
				}
				return $item;
			});
			$result[$storage->getID()] = $storage;
		}

		return $result;
	}

	/**
	 * Get a priority 'type', where a bigger number means higher priority
	 * user applicable > group applicable > 'all'
	 *
	 * @param IStorageConfig $storage
	 * @return int
	 */
	protected function getPriorityType(IStorageConfig $storage) {
		$applicableUsers = $storage->getApplicableUsers();
		$applicableGroups = $storage->getApplicableGroups();

		if ($applicableUsers && $applicableUsers[0] !== 'all') {
			return 2;
		}
		if ($applicableGroups) {
			return 1;
		}
		return 0;
	}

	protected function isApplicable(IStorageConfig $config) {
		$applicableUsers = $config->getApplicableUsers();
		$applicableGroups = $config->getApplicableGroups();

		if (\count($applicableUsers) === 0 && \count($applicableGroups) === 0) {
			return true;
		}
		if (\in_array($this->getUser()->getUID(), $applicableUsers, true)) {
			return true;
		}
		$groupIds = $this->groupManager->getUserGroupIds($this->getUser());
		foreach ($groupIds as $groupId) {
			if (\in_array($groupId, $applicableGroups, true)) {
				return true;
			}
		}
		return false;
	}
}
