<?php
/**
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Stefan Weil <sw@weilnetz.de>
 * @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 OC\Files\Filesystem;

use OCP\Files\External\IStorageConfig;
use OCP\Files\External\IStoragesBackendService;
use OCP\Files\External\Service\IGlobalStoragesService;
use OCP\IUser;

/**
 * Service class to manage global external storages
 */
class GlobalStoragesService extends StoragesService implements IGlobalStoragesService {
	/**
	 * Triggers $signal for all applicable users of the given
	 * storage
	 *
	 * @param IStorageConfig $storage storage data
	 * @param string $signal signal to trigger
	 */
	protected function triggerHooks(IStorageConfig $storage, $signal) {
		// FIXME: Use as expression in empty once PHP 5.4 support is dropped
		$applicableUsers = $storage->getApplicableUsers();
		$applicableGroups = $storage->getApplicableGroups();
		if (empty($applicableUsers) && empty($applicableGroups)) {
			// raise for user "all"
			$this->triggerApplicableHooks(
				$signal,
				$storage->getMountPoint(),
				IStorageConfig::MOUNT_TYPE_USER,
				['all']
			);
			return;
		}

		$this->triggerApplicableHooks(
			$signal,
			$storage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_USER,
			$applicableUsers
		);
		$this->triggerApplicableHooks(
			$signal,
			$storage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_GROUP,
			$applicableGroups
		);
	}

	/**
	 * Triggers signal_create_mount or signal_delete_mount to
	 * accommodate for additions/deletions in applicableUsers
	 * and applicableGroups fields.
	 *
	 * @param IStorageConfig $oldStorage old storage config
	 * @param IStorageConfig $newStorage new storage config
	 */
	protected function triggerChangeHooks(IStorageConfig $oldStorage, IStorageConfig $newStorage) {
		// if mount point changed, it's like a deletion + creation
		if ($oldStorage->getMountPoint() !== $newStorage->getMountPoint()) {
			$this->triggerHooks($oldStorage, Filesystem::signal_delete_mount);
			$this->triggerHooks($newStorage, Filesystem::signal_create_mount);
			return;
		}

		$userAdditions = \array_diff($newStorage->getApplicableUsers(), $oldStorage->getApplicableUsers());
		$userDeletions = \array_diff($oldStorage->getApplicableUsers(), $newStorage->getApplicableUsers());
		$groupAdditions = \array_diff($newStorage->getApplicableGroups(), $oldStorage->getApplicableGroups());
		$groupDeletions = \array_diff($oldStorage->getApplicableGroups(), $newStorage->getApplicableGroups());

		// FIXME: Use as expression in empty once PHP 5.4 support is dropped
		// if no applicable were set, raise a signal for "all"
		$oldApplicableUsers = $oldStorage->getApplicableUsers();
		$oldApplicableGroups = $oldStorage->getApplicableGroups();
		if (empty($oldApplicableUsers) && empty($oldApplicableGroups)) {
			$this->triggerApplicableHooks(
				Filesystem::signal_delete_mount,
				$oldStorage->getMountPoint(),
				IStorageConfig::MOUNT_TYPE_USER,
				['all']
			);
		}

		// trigger delete for removed users
		$this->triggerApplicableHooks(
			Filesystem::signal_delete_mount,
			$oldStorage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_USER,
			$userDeletions
		);

		// trigger delete for removed groups
		$this->triggerApplicableHooks(
			Filesystem::signal_delete_mount,
			$oldStorage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_GROUP,
			$groupDeletions
		);

		// and now add the new users
		$this->triggerApplicableHooks(
			Filesystem::signal_create_mount,
			$newStorage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_USER,
			$userAdditions
		);

		// and now add the new groups
		$this->triggerApplicableHooks(
			Filesystem::signal_create_mount,
			$newStorage->getMountPoint(),
			IStorageConfig::MOUNT_TYPE_GROUP,
			$groupAdditions
		);

		// FIXME: Use as expression in empty once PHP 5.4 support is dropped
		// if no applicable, raise a signal for "all"
		$newApplicableUsers = $newStorage->getApplicableUsers();
		$newApplicableGroups = $newStorage->getApplicableGroups();
		if (empty($newApplicableUsers) && empty($newApplicableGroups)) {
			$this->triggerApplicableHooks(
				Filesystem::signal_create_mount,
				$newStorage->getMountPoint(),
				IStorageConfig::MOUNT_TYPE_USER,
				['all']
			);
		}
	}

	/**
	 * Get the visibility type for this controller, used in validation
	 *
	 * @return string IStoragesBackendService::VISIBILITY_* constants
	 */
	public function getVisibilityType() {
		return IStoragesBackendService::VISIBILITY_ADMIN;
	}

	protected function isApplicable(IStorageConfig $config) {
		return true;
	}

	/**
	 * Get all configured admin and personal mounts
	 *
	 * @return array map of storage id to storage config
	 */
	public function getStorageForAllUsers() {
		$mounts = $this->dbConfig->getAllMounts();
		$configs = \array_map([$this, 'getStorageConfigFromDBMount'], $mounts);
		$configs = \array_filter($configs, function ($config) {
			return $config instanceof IStorageConfig;
		});

		$keys = \array_map(function (IStorageConfig $config) {
			return $config->getId();
		}, $configs);

		return \array_combine($keys, $configs);
	}

	/**
	 * Deletes the external storages mounted to the user
	 *
	 * @param IUser $user
	 * @return bool
	 */
	public function deleteAllForUser($user) {
		$userId = $user->getUID();
		$result = false;
		//Get all valid storages
		$mounts = $this->getStorages();
		foreach ($mounts as $mount) {
			$applicableUsers = $mount->getApplicableUsers();
			$id = $mount->getId();
			if (\in_array($userId, $applicableUsers, true)) {
				if (\count($applicableUsers) === 1) {
					//As this storage is associated only with this user.
					$this->removeStorage($id);
					$result = true;
				} else {
					$storage = $this->getStorage($id);
					$userIndex = \array_search($userId, $applicableUsers, true);
					unset($applicableUsers[$userIndex]);
					$storage->setApplicableUsers($applicableUsers);
					$this->updateStorage($storage);
					$result = true;
				}
			}
		}
		return $result;
	}
}
