<?php
/**
 * @author Björn Schießle <schiessle@owncloud.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 *
 * @copyright Copyright (c) 2015, ownCloud, Inc.
 * @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_Encryption;

/**
 * Class for hook specific logic
 */
class Hooks {

	// file for which we want to rename the keys after the rename operation was successful
	private static $renamedFiles = array();
	// file for which we want to delete the keys after the delete operation was successful
	private static $deleteFiles = array();
	// file for which we want to delete the keys after the delete operation was successful
	private static $unmountedFiles = array();


	/*
	 * check if files can be encrypted to every user.
	 */
	/**
	 * @param array $params
	 */
	public static function preShared($params) {

		if (\OCP\App::isEnabled('files_encryption') === false) {
			return true;
		}

		$l = new \OC_L10N('files_encryption');
		$users = array();
		$view = new \OC\Files\View('/');

		switch ($params['shareType']) {
			case \OCP\Share::SHARE_TYPE_USER:
				$users[] = $params['shareWith'];
				break;
			case \OCP\Share::SHARE_TYPE_GROUP:
				$users = \OC_Group::usersInGroup($params['shareWith']);
				break;
		}

		$notConfigured = array();
		foreach ($users as $user) {
			if (!Keymanager::publicKeyExists($view, $user)) {
				$notConfigured[] = $user;
			}
		}

		if (count($notConfigured) > 0) {
			$params['run'] = false;
			$params['error'] = $l->t('Following users are not set up for encryption:') . ' ' . join(', ' , $notConfigured);
		}

	}

	/**
	 * update share keys if a file was shared
	 */
	public static function postShared($params) {

		if (\OCP\App::isEnabled('files_encryption') === false) {
			return true;
		}

		if ($params['itemType'] === 'file' || $params['itemType'] === 'folder') {

			$path = \OC\Files\Filesystem::getPath($params['fileSource']);

			self::updateKeyfiles($path);
		}
	}

	/**
	 * update keyfiles and share keys recursively
	 *
	 * @param string $path to the file/folder
	 */
	private static function updateKeyfiles($path) {
		$view = new \OC\Files\View('/');
		$userId = \OCP\User::getUser();
		$session = new Session($view);
		$util = new Util($view, $userId);
		$sharingEnabled = \OCP\Share::isEnabled();

		$mountManager = \OC\Files\Filesystem::getMountManager();
		$mount = $mountManager->find('/' . $userId . '/files' . $path);
		$mountPoint = $mount->getMountPoint();

		// if a folder was shared, get a list of all (sub-)folders
		if ($view->is_dir('/' . $userId . '/files' . $path)) {
			$allFiles = $util->getAllFiles($path, $mountPoint);
		} else {
			$allFiles = array($path);
		}

		foreach ($allFiles as $path) {
			$usersSharing = $util->getSharingUsersArray($sharingEnabled, $path);
			$util->setSharedFileKeyfiles($session, $usersSharing, $path);
		}
	}

	/**
	 * unshare file/folder from a user with whom you shared the file before
	 */
	public static function postUnshare($params) {

		if (\OCP\App::isEnabled('files_encryption') === false) {
			return true;
		}

		if ($params['itemType'] === 'file' || $params['itemType'] === 'folder') {

			$view = new \OC\Files\View('/');
			$userId = $params['uidOwner'];
			$userView = new \OC\Files\View('/' . $userId . '/files');
			$util = new Util($view, $userId);
			$path = $userView->getPath($params['fileSource']);

			// for group shares get a list of the group members
			if ($params['shareType'] === \OCP\Share::SHARE_TYPE_GROUP) {
				$userIds = \OC_Group::usersInGroup($params['shareWith']);
			} else {
				if ($params['shareType'] === \OCP\Share::SHARE_TYPE_LINK || $params['shareType'] === \OCP\Share::SHARE_TYPE_REMOTE) {
					$userIds = array($util->getPublicShareKeyId());
				} else {
					$userIds = array($params['shareWith']);
				}
			}

			$mountManager = \OC\Files\Filesystem::getMountManager();
			$mount = $mountManager->find('/' . $userId . '/files' . $path);
			$mountPoint = $mount->getMountPoint();

			// if we unshare a folder we need a list of all (sub-)files
			if ($params['itemType'] === 'folder') {
				$allFiles = $util->getAllFiles($path, $mountPoint);
			} else {
				$allFiles = array($path);
			}

			foreach ($allFiles as $path) {

				// check if the user still has access to the file, otherwise delete share key
				$sharingUsers = $util->getSharingUsersArray(true, $path);

				// Unshare every user who no longer has access to the file
				$delUsers = array_diff($userIds, $sharingUsers);
				$keyPath = Keymanager::getKeyPath($view, $util, $path);

				// delete share key
				Keymanager::delShareKey($view, $delUsers, $keyPath, $userId, $path);
			}

		}
	}

	/**
	 * mark file as renamed so that we know the original source after the file was renamed
	 * @param array $params with the old path and the new path
	 */
	public static function preRename($params) {
		self::preRenameOrCopy($params, 'rename');
	}

	/**
	 * mark file as copied so that we know the original source after the file was copied
	 * @param array $params with the old path and the new path
	 */
	public static function preCopy($params) {
		self::preRenameOrCopy($params, 'copy');
	}

	private static function preRenameOrCopy($params, $operation) {
		$user = \OCP\User::getUser();
		$view = new \OC\Files\View('/');
		$util = new Util($view, $user);

		// we only need to rename the keys if the rename happens on the same mountpoint
		// otherwise we perform a stream copy, so we get a new set of keys
		$oldPath = \OC\Files\Filesystem::normalizePath('/' . $user . '/files/' . $params['oldpath']);
		$newPath = \OC\Files\Filesystem::normalizePath('/' . $user . '/files/' . $params['newpath']);
		$mp1 = $view->getMountPoint($oldPath);
		$mp2 = $view->getMountPoint($newPath);

		$oldKeysPath = Keymanager::getKeyPath($view, $util, $params['oldpath']);

		if ($mp1 === $mp2) {
			self::$renamedFiles[$params['oldpath']] = array(
				'operation' => $operation,
				'oldKeysPath' => $oldKeysPath,
				);
		} elseif ($mp1 !== $oldPath . '/') {
			self::$renamedFiles[$params['oldpath']] = array(
				'operation' => 'cleanup',
				'oldKeysPath' => $oldKeysPath,
				);
		}
	}

	/**
	 * after a file is renamed/copied, rename/copy its keyfile and share-keys also fix the file size and fix also the sharing
	 *
	 * @param array $params array with oldpath and newpath
	 */
	public static function postRenameOrCopy($params) {

		if (\OCP\App::isEnabled('files_encryption') === false) {
			return true;
		}

		$view = new \OC\Files\View('/');
		$userId = \OCP\User::getUser();
		$util = new Util($view, $userId);

		if (isset(self::$renamedFiles[$params['oldpath']]['operation']) &&
				isset(self::$renamedFiles[$params['oldpath']]['oldKeysPath'])) {
			$operation = self::$renamedFiles[$params['oldpath']]['operation'];
			$oldKeysPath = self::$renamedFiles[$params['oldpath']]['oldKeysPath'];
			unset(self::$renamedFiles[$params['oldpath']]);
			if ($operation === 'cleanup') {
				return $view->unlink($oldKeysPath);
			}
		} else {
			\OCP\Util::writeLog('Encryption library', "can't get path and owner from the file before it was renamed", \OCP\Util::DEBUG);
			return false;
		}

		list($ownerNew, $pathNew) = $util->getUidAndFilename($params['newpath']);

		if ($util->isSystemWideMountPoint($pathNew)) {
			$newKeysPath =  'files_encryption/keys/' . $pathNew;
		} else {
			$newKeysPath = $ownerNew . '/files_encryption/keys/' . $pathNew;
		}

		// create  key folders if it doesn't exists
		if (!$view->file_exists(dirname($newKeysPath))) {
			$view->mkdir(dirname($newKeysPath));
		}

		$view->$operation($oldKeysPath, $newKeysPath);

		// update sharing-keys
		self::updateKeyfiles($params['newpath']);
	}

	/**
	 * set migration status and the init status back to '0' so that all new files get encrypted
	 * if the app gets enabled again
	 * @param array $params contains the app ID
	 */
	public static function preDisable($params) {
		if ($params['app'] === 'files_encryption') {

			\OC::$server->getConfig()->deleteAppFromAllUsers('files_encryption');

			$session = new Session(new \OC\Files\View('/'));
			$session->setInitialized(Session::NOT_INITIALIZED);
		}
	}

	/**
	 * set the init status to 'NOT_INITIALIZED' (0) if the app gets enabled
	 * @param array $params contains the app ID
	 */
	public static function postEnable($params) {
		if ($params['app'] === 'files_encryption') {
			$session = new Session(new \OC\Files\View('/'));
			$session->setInitialized(Session::NOT_INITIALIZED);
		}
	}

	/**
	 * if the file was really deleted we remove the encryption keys
	 * @param array $params
	 * @return boolean|null
	 */
	public static function postDelete($params) {

		$path = $params[\OC\Files\Filesystem::signal_param_path];

		if (!isset(self::$deleteFiles[$path])) {
			return true;
		}

		$deletedFile = self::$deleteFiles[$path];
		$keyPath = $deletedFile['keyPath'];

		// we don't need to remember the file any longer
		unset(self::$deleteFiles[$path]);

		$view = new \OC\Files\View('/');

		// return if the file still exists and wasn't deleted correctly
		if ($view->file_exists('/' . \OCP\User::getUser() . '/files/' . $path)) {
			return true;
		}

		// Delete keyfile & shareKey so it isn't orphaned
		$view->unlink($keyPath);

	}

	/**
	 * remember the file which should be deleted and it's owner
	 * @param array $params
	 * @return boolean|null
	 */
	public static function preDelete($params) {
		$view = new \OC\Files\View('/');
		$path = $params[\OC\Files\Filesystem::signal_param_path];

		// skip this method if the trash bin is enabled or if we delete a file
		// outside of /data/user/files
		if (\OCP\App::isEnabled('files_trashbin')) {
			return true;
		}

		$util = new Util($view, \OCP\USER::getUser());

		$keysPath = Keymanager::getKeyPath($view, $util, $path);

		self::$deleteFiles[$path] = array(
			'keyPath' => $keysPath);
	}

	/**
	 * unmount file from yourself
	 * remember files/folders which get unmounted
	 */
	public static function preUnmount($params) {
		$view = new \OC\Files\View('/');
		$user = \OCP\User::getUser();
		$path = $params[\OC\Files\Filesystem::signal_param_path];

		$util = new Util($view, $user);
		list($owner, $ownerPath) = $util->getUidAndFilename($path);

		$keysPath = Keymanager::getKeyPath($view, $util, $path);

		self::$unmountedFiles[$path] = array(
			'keyPath' => $keysPath,
			'owner' => $owner,
			'ownerPath' => $ownerPath
		);
	}

	/**
	 * unmount file from yourself
	 */
	public static function postUnmount($params) {

		$path = $params[\OC\Files\Filesystem::signal_param_path];
		$user = \OCP\User::getUser();

		if (!isset(self::$unmountedFiles[$path])) {
			return true;
		}

		$umountedFile = self::$unmountedFiles[$path];
		$keyPath = $umountedFile['keyPath'];
		$owner = $umountedFile['owner'];
		$ownerPath = $umountedFile['ownerPath'];

		$view = new \OC\Files\View();

		// we don't need to remember the file any longer
		unset(self::$unmountedFiles[$path]);

		// check if the user still has access to the file, otherwise delete share key
		$sharingUsers = \OCP\Share::getUsersSharingFile($path, $user);
		if (!in_array($user, $sharingUsers['users'])) {
			Keymanager::delShareKey($view, array($user), $keyPath, $owner, $ownerPath);
		}
	}

}