<?php
/**
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 *
 * @copyright Copyright (c) 2017, 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\Config;

use OC\Hooks\Emitter;
use OC\Hooks\EmitterTrait;
use OCP\Files\Config\IHomeMountProvider;
use OCP\Files\Config\IMountProviderCollection;
use OCP\Files\Config\IMountProvider;
use OCP\Files\Config\IUserMountCache;
use OCP\Files\Mount\IMountPoint;
use OCP\Files\Storage\IStorageFactory;
use OCP\IUser;

class MountProviderCollection implements IMountProviderCollection, Emitter {
	use EmitterTrait;

	/**
	 * @var \OCP\Files\Config\IHomeMountProvider[]
	 */
	private $homeProviders = [];

	/**
	 * @var \OCP\Files\Config\IMountProvider[]
	 */
	private $providers = [];

	/**
	 * @var \OCP\Files\Storage\IStorageFactory
	 */
	private $loader;

	/**
	 * @var \OCP\Files\Config\IUserMountCache
	 */
	private $mountCache;

	/**
	 * @param \OCP\Files\Storage\IStorageFactory $loader
	 * @param IUserMountCache $mountCache
	 */
	public function __construct(IStorageFactory $loader, IUserMountCache $mountCache) {
		$this->loader = $loader;
		$this->mountCache = $mountCache;
	}

	/**
	 * Get all configured mount points for the user
	 *
	 * @param \OCP\IUser $user
	 * @return \OCP\Files\Mount\IMountPoint[]
	 */
	public function getMountsForUser(IUser $user) {
		$loader = $this->loader;
		$mounts = array_map(function (IMountProvider $provider) use ($user, $loader) {
			return $provider->getMountsForUser($user, $loader);
		}, $this->providers);
		$mounts = array_filter($mounts, function ($result) {
			return is_array($result);
		});
		return array_reduce($mounts, function (array $mounts, array $providerMounts) {
			return array_merge($mounts, $providerMounts);
		}, []);
	}

	/**
	 * Get the configured home mount for this user
	 *
	 * @param \OCP\IUser $user
	 * @return \OCP\Files\Mount\IMountPoint
	 * @since 9.1.0
	 */
	public function getHomeMountForUser(IUser $user) {
		/** @var \OCP\Files\Config\IHomeMountProvider[] $providers */
		$providers = array_reverse($this->homeProviders); // call the latest registered provider first to give apps an opportunity to overwrite builtin
		foreach ($providers as $homeProvider) {
			if ($mount = $homeProvider->getHomeMountForUser($user, $this->loader)) {
				$mount->setMountPoint('/' . $user->getUID()); //make sure the mountpoint is what we expect
				return $mount;
			}
		}
		throw new \Exception('No home storage configured for user ' . $user);
	}

	/**
	 * Add a provider for mount points
	 *
	 * @param \OCP\Files\Config\IMountProvider $provider
	 */
	public function registerProvider(IMountProvider $provider) {
		$this->providers[] = $provider;
		$this->emit('\OC\Files\Config', 'registerMountProvider', [$provider]);
	}

	/**
	 * Add a provider for home mount points
	 *
	 * @param \OCP\Files\Config\IHomeMountProvider $provider
	 * @since 9.1.0
	 */
	public function registerHomeProvider(IHomeMountProvider $provider) {
		$this->homeProviders[] = $provider;
		$this->emit('\OC\Files\Config', 'registerHomeMountProvider', [$provider]);
	}

	/**
	 * Cache mounts for user
	 *
	 * @param IUser $user
	 * @param IMountPoint[] $mountPoints
	 */
	public function registerMounts(IUser $user, array $mountPoints) {
		$this->mountCache->registerMounts($user, $mountPoints);
	}

	/**
	 * Get the mount cache which can be used to search for mounts without setting up the filesystem
	 *
	 * @return IUserMountCache
	 */
	public function getMountCache() {
		return $this->mountCache;
	}
}
