<?php
  /**
  * ownCloud
  *
  * @author Michael Gapczynski
  * @copyright 2012 Michael Gapczynski mtgap@owncloud.com

  * @copyright 2014 Vincent Petry <pvince81@owncloud.com>
  * @copyright 2014 Robin McCorkell <rmccorkell@karoshi.org.uk>

  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
  * License as published by the Free Software Foundation; either
  * version 3 of the License, or any later version.
  *
  * This library 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 along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
  
  /**

   * Class to configure mount.json globally and for users
   */

  class OC_Mount_Config {

  	// TODO: make this class non-static and give it a proper namespace

  
  	const MOUNT_TYPE_GLOBAL = 'global';
  	const MOUNT_TYPE_GROUP = 'group';
  	const MOUNT_TYPE_USER = 'user';

  	const MOUNT_TYPE_PERSONAL = 'personal';
  
  	// whether to skip backend test (for unit tests, as this static class is not mockable)
  	public static $skipTest = false;
  
  	private static $backends = array();
  
  	/**
  	 * @param string $class
  	 * @param array $definition
  	 * @return bool
  	 */
  	public static function registerBackend($class, $definition) {
  		if (!isset($definition['backend'])) {
  			return false;
  		}
  
  		OC_Mount_Config::$backends[$class] = $definition;
  		return true;
  	}
  
  	/**
  	 * Setup backends
  	 *
  	 * @return array of previously registered backends
  	 */
  	public static function setUp($backends = array()) {
  		$backup = self::$backends;
  		self::$backends = $backends;
  
  		return $backup;
  	}

  
  	/**
  	* Get details on each of the external storage backends, used for the mount config UI
  	* If a custom UI is needed, add the key 'custom' and a javascript file with that name will be loaded
  	* If the configuration parameter should be secret, add a '*' to the beginning of the value
  	* If the configuration parameter is a boolean, add a '!' to the beginning of the value
  	* If the configuration parameter is optional, add a '&' to the beginning of the value
  	* If the configuration parameter is hidden, add a '#' to the beginning of the value
  	* @return array
  	*/
  	public static function getBackends() {

  		$sortFunc = function($a, $b) {
  			return strcasecmp($a['backend'], $b['backend']);
  		};
  
  		$backEnds = array();
  
  		foreach (OC_Mount_Config::$backends as $class => $backend) {
  			if (isset($backend['has_dependencies']) and $backend['has_dependencies'] === true) {
  				if (!method_exists($class, 'checkDependencies')) {
  					\OCP\Util::writeLog('files_external',
  						"Backend class $class has dependencies but doesn't provide method checkDependencies()",
  						\OCP\Util::DEBUG);
  					continue;
  				} elseif ($class::checkDependencies() !== true) {
  					continue;
  				}
  			}
  			$backEnds[$class] = $backend;
  		}
  
  		uasort($backEnds, $sortFunc);
  
  		return $backEnds;
  	}
  
  	/**
  	 * Hook that mounts the given user's visible mount points
  	 * @param array $data
  	 */
  	public static function initMountPointsHook($data) {
  		$mountPoints = self::getAbsoluteMountPoints($data['user']);
  		$loader = \OC\Files\Filesystem::getLoader();
  		$manager = \OC\Files\Filesystem::getMountManager();
  		foreach ($mountPoints as $mountPoint => $options) {
  			if (isset($options['options']['objectstore'])) {
  				$objectClass = $options['options']['objectstore']['class'];
  				$options['options']['objectstore'] = new $objectClass($options['options']['objectstore']);
  			}
  			if (isset($options['personal']) && $options['personal']) {
  				$mount = new \OCA\Files_External\PersonalMount($options['class'], $mountPoint, $options['options'], $loader);
  			} else{
  				$mount = new \OC\Files\Mount\Mount($options['class'], $mountPoint, $options['options'], $loader);
  			}
  			$manager->addMount($mount);
  		}
  	}
  
  	/**
  	 * Returns the mount points for the given user.
  	 * The mount point is relative to the data directory.
  	 *
  	 * @param string $user user
  	 * @return array of mount point string as key, mountpoint config as value
  	 */
  	public static function getAbsoluteMountPoints($user) {
  		$mountPoints = array();
  
  		$datadir = \OC_Config::getValue("datadirectory", \OC::$SERVERROOT . "/data");
  		$mount_file = \OC_Config::getValue("mount_file", $datadir . "/mount.json");
  
  		$backends = self::getBackends();
  
  		//move config file to it's new position
  		if (is_file(\OC::$SERVERROOT . '/config/mount.json')) {
  			rename(\OC::$SERVERROOT . '/config/mount.json', $mount_file);
  		}
  
  		// Load system mount points
  		$mountConfig = self::readData();
  
  		// Global mount points (is this redundant?)
  		if (isset($mountConfig[self::MOUNT_TYPE_GLOBAL])) {
  			foreach ($mountConfig[self::MOUNT_TYPE_GLOBAL] as $mountPoint => $options) {
  				$options['personal'] = false;
  				$options['options'] = self::decryptPasswords($options['options']);
  				if (!isset($options['priority'])) {
  					$options['priority'] = $backends[$options['class']]['priority'];
  				}
  
  				// Override if priority greater
  				if ( (!isset($mountPoints[$mountPoint]))
  					|| ($options['priority'] >= $mountPoints[$mountPoint]['priority']) ) {
  					$options['priority_type'] = self::MOUNT_TYPE_GLOBAL;
  					$options['backend'] = $backends[$options['class']]['backend'];
  					$mountPoints[$mountPoint] = $options;
  				}
  			}
  		}
  		// All user mount points
  		if (isset($mountConfig[self::MOUNT_TYPE_USER]) && isset($mountConfig[self::MOUNT_TYPE_USER]['all'])) {
  			$mounts = $mountConfig[self::MOUNT_TYPE_USER]['all'];
  			foreach ($mounts as $mountPoint => $options) {
  				$mountPoint = self::setUserVars($user, $mountPoint);
  				foreach ($options as &$option) {
  					$option = self::setUserVars($user, $option);
  				}
  				$options['options'] = self::decryptPasswords($options['options']);
  				if (!isset($options['priority'])) {
  					$options['priority'] = $backends[$options['class']]['priority'];
  				}
  
  				// Override if priority greater
  				if ( (!isset($mountPoints[$mountPoint]))
  					|| ($options['priority'] >= $mountPoints[$mountPoint]['priority']) ) {
  					$options['priority_type'] = self::MOUNT_TYPE_GLOBAL;
  					$options['backend'] = $backends[$options['class']]['backend'];
  					$mountPoints[$mountPoint] = $options;
  				}
  			}
  		}
  		// Group mount points
  		if (isset($mountConfig[self::MOUNT_TYPE_GROUP])) {
  			foreach ($mountConfig[self::MOUNT_TYPE_GROUP] as $group => $mounts) {
  				if (\OC_Group::inGroup($user, $group)) {
  					foreach ($mounts as $mountPoint => $options) {
  						$mountPoint = self::setUserVars($user, $mountPoint);
  						foreach ($options as &$option) {
  							$option = self::setUserVars($user, $option);
  						}
  						$options['personal'] = false;
  						$options['options'] = self::decryptPasswords($options['options']);
  						if (!isset($options['priority'])) {
  							$options['priority'] = $backends[$options['class']]['priority'];
  						}
  
  						// Override if priority greater or if priority type different
  						if ( (!isset($mountPoints[$mountPoint]))
  							|| ($options['priority'] >= $mountPoints[$mountPoint]['priority'])
  							|| ($mountPoints[$mountPoint]['priority_type'] !== self::MOUNT_TYPE_GROUP) ) {
  							$options['priority_type'] = self::MOUNT_TYPE_GROUP;
  							$options['backend'] = $backends[$options['class']]['backend'];
  							$mountPoints[$mountPoint] = $options;
  						}
  					}
  				}
  			}
  		}
  		// User mount points
  		if (isset($mountConfig[self::MOUNT_TYPE_USER])) {
  			foreach ($mountConfig[self::MOUNT_TYPE_USER] as $mountUser => $mounts) {
  				if (strtolower($mountUser) === strtolower($user)) {
  					foreach ($mounts as $mountPoint => $options) {
  						$mountPoint = self::setUserVars($user, $mountPoint);
  						foreach ($options as &$option) {
  							$option = self::setUserVars($user, $option);
  						}
  						$options['personal'] = false;
  						$options['options'] = self::decryptPasswords($options['options']);
  						if (!isset($options['priority'])) {
  							$options['priority'] = $backends[$options['class']]['priority'];
  						}
  
  						// Override if priority greater or if priority type different
  						if ( (!isset($mountPoints[$mountPoint]))
  							|| ($options['priority'] >= $mountPoints[$mountPoint]['priority'])
  							|| ($mountPoints[$mountPoint]['priority_type'] !== self::MOUNT_TYPE_USER) ) {
  							$options['priority_type'] = self::MOUNT_TYPE_USER;
  							$options['backend'] = $backends[$options['class']]['backend'];
  							$mountPoints[$mountPoint] = $options;
  						}
  					}
  				}
  			}
  		}
  
  		// Load personal mount points
  		$mountConfig = self::readData($user);
  		if (isset($mountConfig[self::MOUNT_TYPE_USER][$user])) {
  			foreach ($mountConfig[self::MOUNT_TYPE_USER][$user] as $mountPoint => $options) {
  				$options['personal'] = true;
  				$options['options'] = self::decryptPasswords($options['options']);
  
  				// Always override previous config
  				$options['priority_type'] = self::MOUNT_TYPE_PERSONAL;
  				$options['backend'] = $backends[$options['class']]['backend'];
  				$mountPoints[$mountPoint] = $options;
  			}
  		}
  
  		return $mountPoints;
  	}
  
  	/**
  	 * fill in the correct values for $user
  	 *
  	 * @param string $user
  	 * @param string $input
  	 * @return string
  	 */
  	private static function setUserVars($user, $input) {
  		return str_replace('$user', $user, $input);
  	}
  
  
  	/**
  	* Get details on each of the external storage backends, used for the mount config UI
  	* Some backends are not available as a personal backend, f.e. Local and such that have
  	* been disabled by the admin.
  	*
  	* If a custom UI is needed, add the key 'custom' and a javascript file with that name will be loaded
  	* If the configuration parameter should be secret, add a '*' to the beginning of the value
  	* If the configuration parameter is a boolean, add a '!' to the beginning of the value
  	* If the configuration parameter is optional, add a '&' to the beginning of the value
  	* If the configuration parameter is hidden, add a '#' to the beginning of the value
  	* @return array
  	*/
  	public static function getPersonalBackends() {
  
  		// Check whether the user has permissions to add personal storage backends
  		// return an empty array if this is not the case
  		if(OCP\Config::getAppValue('files_external', 'allow_user_mounting', 'yes') !== 'yes') {
  			return array();
  		}
  
  		$backEnds = self::getBackends();

  		// Remove local storage and other disabled storages
  		unset($backEnds['\OC\Files\Storage\Local']);
  
  		$allowedBackEnds = explode(',', OCP\Config::getAppValue('files_external', 'user_mounting_backends', ''));
  		foreach ($backEnds as $backend => $null) {
  			if (!in_array($backend, $allowedBackEnds)) {
  				unset($backEnds[$backend]);

  			}
  		}

  		return $backEnds;

  	}
  
  	/**
  	* Get the system mount points
  	* The returned array is not in the same format as getUserMountPoints()
  	* @return array
  	*/
  	public static function getSystemMountPoints() {

  		$mountPoints = self::readData();

  		$backends = self::getBackends();
  		$system = array();
  		if (isset($mountPoints[self::MOUNT_TYPE_GROUP])) {
  			foreach ($mountPoints[self::MOUNT_TYPE_GROUP] as $group => $mounts) {
  				foreach ($mounts as $mountPoint => $mount) {
  					// Update old classes to new namespace
  					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
  						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
  					}

  					$mount['options'] = self::decryptPasswords($mount['options']);
  					if (!isset($mount['priority'])) {
  						$mount['priority'] = $backends[$mount['class']]['priority'];
  					}

  					// Remove '/$user/files/' from mount point
  					$mountPoint = substr($mountPoint, 13);

  
  					$config = array(
  						'class' => $mount['class'],
  						'mountpoint' => $mountPoint,
  						'backend' => $backends[$mount['class']]['backend'],
  						'priority' => $mount['priority'],
  						'options' => $mount['options'],
  						'applicable' => array('groups' => array($group), 'users' => array()),
  						'status' => self::getBackendStatus($mount['class'], $mount['options'], false)
  					);
  					$hash = self::makeConfigHash($config);
  					// If an existing config exists (with same class, mountpoint and options)
  					if (isset($system[$hash])) {
  						// add the groups into that config
  						$system[$hash]['applicable']['groups']
  							= array_merge($system[$hash]['applicable']['groups'], array($group));

  					} else {

  						$system[$hash] = $config;

  					}
  				}
  			}
  		}
  		if (isset($mountPoints[self::MOUNT_TYPE_USER])) {
  			foreach ($mountPoints[self::MOUNT_TYPE_USER] as $user => $mounts) {
  				foreach ($mounts as $mountPoint => $mount) {
  					// Update old classes to new namespace
  					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
  						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
  					}

  					$mount['options'] = self::decryptPasswords($mount['options']);
  					if (!isset($mount['priority'])) {
  						$mount['priority'] = $backends[$mount['class']]['priority'];
  					}

  					// Remove '/$user/files/' from mount point
  					$mountPoint = substr($mountPoint, 13);

  					$config = array(
  						'class' => $mount['class'],
  						'mountpoint' => $mountPoint,
  						'backend' => $backends[$mount['class']]['backend'],
  						'priority' => $mount['priority'],
  						'options' => $mount['options'],
  						'applicable' => array('groups' => array(), 'users' => array($user)),
  						'status' => self::getBackendStatus($mount['class'], $mount['options'], false)
  					);
  					$hash = self::makeConfigHash($config);
  					// If an existing config exists (with same class, mountpoint and options)
  					if (isset($system[$hash])) {
  						// add the users into that config
  						$system[$hash]['applicable']['users']
  							= array_merge($system[$hash]['applicable']['users'], array($user));

  					} else {

  						$system[$hash] = $config;

  					}
  				}
  			}
  		}

  		return array_values($system);

  	}
  
  	/**
  	* Get the personal mount points of the current user
  	* The returned array is not in the same format as getUserMountPoints()
  	* @return array
  	*/
  	public static function getPersonalMountPoints() {

  		$mountPoints = self::readData(OCP\User::getUser());
  		$backEnds = self::getBackends();

  		$uid = OCP\User::getUser();
  		$personal = array();
  		if (isset($mountPoints[self::MOUNT_TYPE_USER][$uid])) {
  			foreach ($mountPoints[self::MOUNT_TYPE_USER][$uid] as $mountPoint => $mount) {
  				// Update old classes to new namespace
  				if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
  					$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
  				}

  				$mount['options'] = self::decryptPasswords($mount['options']);
  				$personal[] = array(

  					'class' => $mount['class'],

  					// Remove '/uid/files/' from mount point
  					'mountpoint' => substr($mountPoint, strlen($uid) + 8),
  					'backend' => $backEnds[$mount['class']]['backend'],
  					'options' => $mount['options'],
  					'status' => self::getBackendStatus($mount['class'], $mount['options'], true)

  				);
  			}
  		}
  		return $personal;
  	}

  	/**
  	 * Test connecting using the given backend configuration
  	 * @param string $class backend class name
  	 * @param array $options backend configuration options
  	 * @return bool true if the connection succeeded, false otherwise
  	 */
  	private static function getBackendStatus($class, $options, $isPersonal) {
  		if (self::$skipTest) {
  			return true;
  		}

  		foreach ($options as &$option) {

  			$option = self::setUserVars(OCP\User::getUser(), $option);

  		}
  		if (class_exists($class)) {
  			try {
  				$storage = new $class($options);

  				return $storage->test($isPersonal);

  			} catch (Exception $exception) {

  				\OCP\Util::logException('files_external', $exception);

  				return false;
  			}
  		}
  		return false;
  	}
  
  	/**
  	* Add a mount point to the filesystem

  	* @param string $mountPoint Mount point
  	* @param string $class Backend class
  	* @param array $classOptions Backend parameters for the class
  	* @param string $mountType MOUNT_TYPE_GROUP | MOUNT_TYPE_USER
  	* @param string $applicable User or group to apply mount to
  	* @param bool $isPersonal Personal or system mount point i.e. is this being called from the personal or admin page
  	* @param int|null $priority Mount point priority, null for default
  	* @return boolean

  	*/
  	public static function addMountPoint($mountPoint,
  										 $class,
  										 $classOptions,
  										 $mountType,
  										 $applicable,

  										 $isPersonal = false,
  										 $priority = null) {

  		$backends = self::getBackends();

  		$mountPoint = OC\Files\Filesystem::normalizePath($mountPoint);

  		if ($mountPoint === '' || $mountPoint === '/') {
  			// can't mount at root folder

  			return false;
  		}

  
  		if (!isset($backends[$class])) {
  			// invalid backend
  			return false;

  		}

  		if ($isPersonal) {
  			// Verify that the mount point applies for the current user

  			// Prevent non-admin users from mounting local storage and other disabled backends
  			$allowed_backends = self::getPersonalBackends();
  			if ($applicable != OCP\User::getUser() || !isset($allowed_backends[$class])) {

  				return false;
  			}
  			$mountPoint = '/'.$applicable.'/files/'.ltrim($mountPoint, '/');
  		} else {
  			$mountPoint = '/$user/files/'.ltrim($mountPoint, '/');
  		}

  
  		$mount = array($applicable => array(
  			$mountPoint => array(
  				'class' => $class,
  				'options' => self::encryptPasswords($classOptions))
  			)
  		);
  		if (! $isPersonal && !is_null($priority)) {
  			$mount[$applicable][$mountPoint]['priority'] = $priority;
  		}
  
  		$mountPoints = self::readData($isPersonal ? OCP\User::getUser() : NULL);
  		$mountPoints = self::mergeMountPoints($mountPoints, $mount, $mountType);
  
  		// Set default priority if none set
  		if (!isset($mountPoints[$mountType][$applicable][$mountPoint]['priority'])) {
  			if (isset($backends[$class]['priority'])) {
  				$mountPoints[$mountType][$applicable][$mountPoint]['priority']
  					= $backends[$class]['priority'];

  			} else {

  				$mountPoints[$mountType][$applicable][$mountPoint]['priority']
  					= 100;

  			}

  		}

  
  		self::writeData($isPersonal ? OCP\User::getUser() : NULL, $mountPoints);
  
  		return self::getBackendStatus($class, $classOptions, $isPersonal);

  	}
  
  	/**
  	*

  	* @param string $mountPoint Mount point
  	* @param string $mountType MOUNT_TYPE_GROUP | MOUNT_TYPE_USER
  	* @param string $applicable User or group to remove mount from
  	* @param bool $isPersonal Personal or system mount point

  	* @return bool
  	*/
  	public static function removeMountPoint($mountPoint, $mountType, $applicable, $isPersonal = false) {
  		// Verify that the mount point applies for the current user
  		if ($isPersonal) {
  			if ($applicable != OCP\User::getUser()) {
  				return false;
  			}
  			$mountPoint = '/'.$applicable.'/files/'.ltrim($mountPoint, '/');
  		} else {
  			$mountPoint = '/$user/files/'.ltrim($mountPoint, '/');
  		}

  		$mountPoint = \OC\Files\Filesystem::normalizePath($mountPoint);
  		$mountPoints = self::readData($isPersonal ? OCP\User::getUser() : NULL);

  		// Remove mount point
  		unset($mountPoints[$mountType][$applicable][$mountPoint]);
  		// Unset parent arrays if empty
  		if (empty($mountPoints[$mountType][$applicable])) {
  			unset($mountPoints[$mountType][$applicable]);
  			if (empty($mountPoints[$mountType])) {
  				unset($mountPoints[$mountType]);
  			}
  		}

  		self::writeData($isPersonal ? OCP\User::getUser() : NULL, $mountPoints);
  		return true;
  	}
  
  	/**
  	 *
  	 * @param string $mountPoint Mount point
  	 * @param string $target The new mount point
  	 * @param string $mountType MOUNT_TYPE_GROUP | MOUNT_TYPE_USER
  	 * @return bool
  	 */
  	public static function movePersonalMountPoint($mountPoint, $target, $mountType) {
  		$mountPoint = rtrim($mountPoint, '/');
  		$user = OCP\User::getUser();
  		$mountPoints = self::readData($user);
  		if (!isset($mountPoints[$mountType][$user][$mountPoint])) {
  			return false;
  		}
  		$mountPoints[$mountType][$user][$target] = $mountPoints[$mountType][$user][$mountPoint];
  		// Remove old mount point
  		unset($mountPoints[$mountType][$user][$mountPoint]);
  
  		self::writeData($user, $mountPoints);

  		return true;
  	}
  
  	/**
  	* Read the mount points in the config file into an array

  	* @param string|null $user If not null, personal for $user, otherwise system

  	* @return array
  	*/

  	private static function readData($user = NULL) {

  		$parser = new \OC\ArrayParser();

  		if (isset($user)) {
  			$phpFile = OC_User::getHome($user).'/mount.php';
  			$jsonFile = OC_User::getHome($user).'/mount.json';

  		} else {

  			$phpFile = OC::$SERVERROOT.'/config/mount.php';

  			$datadir = \OC_Config::getValue('datadirectory', \OC::$SERVERROOT . '/data/');
  			$jsonFile = \OC_Config::getValue('mount_file', $datadir . '/mount.json');

  		}
  		if (is_file($jsonFile)) {
  			$mountPoints = json_decode(file_get_contents($jsonFile), true);
  			if (is_array($mountPoints)) {
  				return $mountPoints;
  			}
  		} elseif (is_file($phpFile)) {
  			$mountPoints = $parser->parsePHP(file_get_contents($phpFile));
  			if (is_array($mountPoints)) {
  				return $mountPoints;
  			}
  		}
  		return array();
  	}
  
  	/**
  	* Write the mount points to the config file

  	* @param string|null $user If not null, personal for $user, otherwise system
  	* @param array $data Mount points

  	*/

  	private static function writeData($user, $data) {
  		if (isset($user)) {
  			$file = OC_User::getHome($user).'/mount.json';

  		} else {

  			$datadir = \OC_Config::getValue('datadirectory', \OC::$SERVERROOT . '/data/');
  			$file = \OC_Config::getValue('mount_file', $datadir . '/mount.json');
  		}
  		$options = 0;
  		if (defined('JSON_PRETTY_PRINT')) {
  			// only for PHP >= 5.4
  			$options = JSON_PRETTY_PRINT;

  		}

  		$content = json_encode($data, $options);

  		@file_put_contents($file, $content);

  		@chmod($file, 0640);

  	}
  
  	/**
  	 * Returns all user uploaded ssl root certificates
  	 * @return array
  	 */
  	public static function getCertificates() {

  		$path=OC_User::getHome(OC_User::getUser()) . '/files_external/uploads/';

  		\OCP\Util::writeLog('files_external', 'checking path '.$path, \OCP\Util::INFO);
  		if ( ! is_dir($path)) {
  			//path might not exist (e.g. non-standard OC_User::getHome() value)
  			//in this case create full path using 3rd (recursive=true) parameter.
  			mkdir($path, 0777, true);
  		}
  		$result = array();
  		$handle = opendir($path);

  		if(!is_resource($handle)) {

  			return array();
  		}
  		while (false !== ($file = readdir($handle))) {
  			if ($file != '.' && $file != '..') $result[] = $file;
  		}
  		return $result;
  	}
  
  	/**
  	 * creates certificate bundle
  	 */
  	public static function createCertificateBundle() {

  		$path=OC_User::getHome(OC_User::getUser()) . '/files_external';

  
  		$certs = OC_Mount_Config::getCertificates();
  		$fh_certs = fopen($path."/rootcerts.crt", 'w');
  		foreach ($certs as $cert) {
  			$file=$path.'/uploads/'.$cert;
  			$fh = fopen($file, "r");
  			$data = fread($fh, filesize($file));
  			fclose($fh);
  			if (strpos($data, 'BEGIN CERTIFICATE')) {
  				fwrite($fh_certs, $data);
  				fwrite($fh_certs, "\r
  ");
  			}
  		}
  
  		fclose($fh_certs);
  
  		return true;
  	}
  
  	/**

  	 * check dependencies

  	 */

  	public static function checkDependencies() {
  		$dependencies = array();
  		foreach (OC_Mount_Config::$backends as $class => $backend) {
  			if (isset($backend['has_dependencies']) and $backend['has_dependencies'] === true) {
  				$result = $class::checkDependencies();
  				if ($result !== true) {
  					if (!is_array($result)) {
  						$result = array($result);
  					}
  					foreach ($result as $key => $value) {
  						if (is_numeric($key)) {
  							OC_Mount_Config::addDependency($dependencies, $value, $backend['backend']);
  						} else {
  							OC_Mount_Config::addDependency($dependencies, $key, $backend['backend'], $value);
  						}
  					}
  				}
  			}
  		}
  
  		if (count($dependencies) > 0) {
  			return OC_Mount_Config::generateDependencyMessage($dependencies);

  		}

  		return '';
  	}
  
  	private static function addDependency(&$dependencies, $module, $backend, $message=null) {
  		if (!isset($dependencies[$module])) {
  			$dependencies[$module] = array();
  		}
  
  		if ($message === null) {
  			$dependencies[$module][] = $backend;
  		} else {
  			$dependencies[$module][] = array('backend' => $backend, 'message' => $message);
  		}
  	}
  
  	private static function generateDependencyMessage($dependencies) {
  		$l = new \OC_L10N('files_external');
  		$dependencyMessage = '';
  		foreach ($dependencies as $module => $backends) {
  			$dependencyGroup = array();
  			foreach ($backends as $backend) {
  				if (is_array($backend)) {
  					$dependencyMessage .= '<br />' . $l->t('<b>Note:</b> ') . $backend['message'];
  				} else {
  					$dependencyGroup[] = $backend;
  				}
  			}
  
  			if (count($dependencyGroup) > 0) {
  				$backends = '';
  				for ($i = 0; $i < count($dependencyGroup); $i++) {
  					if ($i > 0 && $i === count($dependencyGroup) - 1) {
  						$backends .= $l->t(' and ');
  					} elseif ($i > 0) {
  						$backends .= ', ';
  					}
  					$backends .= '<i>' . $dependencyGroup[$i] . '</i>';
  				}
  				$dependencyMessage .= '<br />' . OC_Mount_Config::getSingleDependencyMessage($l, $module, $backends);
  			}
  		}
  		return $dependencyMessage;

  	}
  
  	/**

  	 * Returns a dependency missing message
  	 * @param OC_L10N $l
  	 * @param string $module
  	 * @param string $backend
  	 * @return string

  	 */

  	private static function getSingleDependencyMessage($l, $module, $backend) {
  		switch (strtolower($module)) {
  			case 'curl':
  				return $l->t('<b>Note:</b> The cURL support in PHP is not enabled or installed. Mounting of %s is not possible. Please ask your system administrator to install it.', $backend);
  			case 'ftp':
  				return $l->t('<b>Note:</b> The FTP support in PHP is not enabled or installed. Mounting of %s is not possible. Please ask your system administrator to install it.', $backend);
  			default:
  				return $l->t('<b>Note:</b> "%s" is not installed. Mounting of %s is not possible. Please ask your system administrator to install it.', array($module, $backend));

  		}
  	}
  
  	/**

  	 * Encrypt passwords in the given config options
  	 * @param array $options mount options
  	 * @return array updated options

  	 */

  	private static function encryptPasswords($options) {
  		if (isset($options['password'])) {
  			$options['password_encrypted'] = self::encryptPassword($options['password']);
  			// do not unset the password, we want to keep the keys order
  			// on load... because that's how the UI currently works
  			$options['password'] = '';
  		}
  		return $options;

  	}
  
  	/**

  	 * Decrypt passwords in the given config options
  	 * @param array $options mount options
  	 * @return array updated options

  	 */

  	private static function decryptPasswords($options) {
  		// note: legacy options might still have the unencrypted password in the "password" field
  		if (isset($options['password_encrypted'])) {
  			$options['password'] = self::decryptPassword($options['password_encrypted']);
  			unset($options['password_encrypted']);

  		}

  		return $options;
  	}
  
  	/**
  	 * Encrypt a single password
  	 * @param string $password plain text password
  	 * @return string encrypted password
  	 */
  	private static function encryptPassword($password) {
  		$cipher = self::getCipher();
  		$iv = \OCP\Util::generateRandomBytes(16);
  		$cipher->setIV($iv);
  		return base64_encode($iv . $cipher->encrypt($password));
  	}
  
  	/**
  	 * Decrypts a single password
  	 * @param string $encryptedPassword encrypted password
  	 * @return string plain text password
  	 */
  	private static function decryptPassword($encryptedPassword) {
  		$cipher = self::getCipher();
  		$binaryPassword = base64_decode($encryptedPassword);
  		$iv = substr($binaryPassword, 0, 16);
  		$cipher->setIV($iv);
  		$binaryPassword = substr($binaryPassword, 16);
  		return $cipher->decrypt($binaryPassword);
  	}
  
  	/**
  	 * Merges mount points
  	 * @param array $data Existing mount points
  	 * @param array $mountPoint New mount point
  	 * @param string $mountType
  	 * @return array
  	 */
  	private static function mergeMountPoints($data, $mountPoint, $mountType) {
  		$applicable = key($mountPoint);
  		$mountPath = key($mountPoint[$applicable]);
  		if (isset($data[$mountType])) {
  			if (isset($data[$mountType][$applicable])) {
  				// Merge priorities
  				if (isset($data[$mountType][$applicable][$mountPath])
  					&& isset($data[$mountType][$applicable][$mountPath]['priority'])
  					&& !isset($mountPoint[$applicable][$mountPath]['priority'])) {
  					$mountPoint[$applicable][$mountPath]['priority']
  						= $data[$mountType][$applicable][$mountPath]['priority'];
  				}
  				$data[$mountType][$applicable]
  					= array_merge($data[$mountType][$applicable], $mountPoint[$applicable]);
  			} else {
  				$data[$mountType] = array_merge($data[$mountType], $mountPoint);
  			}
  		} else {
  			$data[$mountType] = $mountPoint;

  		}

  		return $data;
  	}
  
  	/**
  	 * Returns the encryption cipher
  	 */
  	private static function getCipher() {
  		if (!class_exists('Crypt_AES', false)) {
  			include('Crypt/AES.php');

  		}

  		$cipher = new Crypt_AES(CRYPT_AES_MODE_CBC);
  		$cipher->setKey(\OCP\Config::getSystemValue('passwordsalt'));
  		return $cipher;
  	}

  	/**
  	 * Computes a hash based on the given configuration.
  	 * This is mostly used to find out whether configurations
  	 * are the same.
  	 */
  	private static function makeConfigHash($config) {
  		$data = json_encode(
  			array(
  				'c' => $config['class'],
  				'm' => $config['mountpoint'],
  				'o' => $config['options']
  			)
  		);
  		return hash('md5', $data);

  	}
  }