<?php
  /**
   * ownCloud
   *
   * @author Frank Karlitschek

   * @copyright 2012 Frank Karlitschek <frank@owncloud.org>
   *

   * @author Jakob Sack

   * @copyright 2012 Jakob Sack <mail@jakobsack.de>
   *
   * @author Georg Ehrke
   * @copyright 2014 Georg Ehrke <georg@ownCloud.com>

   *
   * 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/>.
   *
   */
  
  /**
   * This class manages the apps. It allows them to register and integrate in the

   * ownCloud ecosystem. Furthermore, this class is responsible for installing,

   * upgrading and removing apps.
   */

  class OC_App {

  	static private $settingsForms = array();
  	static private $adminForms = array();
  	static private $personalForms = array();
  	static private $appInfo = array();
  	static private $appTypes = array();
  	static private $loadedApps = array();
  	static private $checkedApps = array();
  	static private $altLogin = array();
  
  	/**

  	 * clean the appId
  	 * @param string|boolean $app AppId that needs to be cleaned

  	 * @return string
  	 */
  	public static function cleanAppId($app) {
  		return str_replace(array('\0', '/', '\\', '..'), '', $app);
  	}
  
  	/**

  	 * loads all apps

  	 * @param array $types
  	 * @return bool
  	 *

  	 * This function walks through the ownCloud directory and loads all apps

  	 * it can find. A directory contains an app if the file /appinfo/app.php
  	 * exists.
  	 *
  	 * if $types is set, only apps of those types will be loaded
  	 */

  	public static function loadApps($types = null) {

  		// Load the enabled apps here
  		$apps = self::getEnabledApps();
  		// prevent app.php from printing output
  		ob_start();

  		foreach ($apps as $app) {
  			if ((is_null($types) or self::isType($app, $types)) && !in_array($app, self::$loadedApps)) {

  				self::$loadedApps[] = $app;

  				self::loadApp($app);

  			}
  		}
  		ob_end_clean();

  		return true;
  	}
  
  	/**
  	 * load a single app

  	 *

  	 * @param string $app
  	 */
  	public static function loadApp($app) {

  		if (is_file(self::getAppPath($app) . '/appinfo/app.php')) {

  			self::checkUpgrade($app);

  			require_once $app . '/appinfo/app.php';

  		}
  	}
  
  	/**
  	 * check if an app is of a specific type

  	 *

  	 * @param string $app

  	 * @param string|array $types

  	 * @return bool
  	 */
  	public static function isType($app, $types) {

  		if (is_string($types)) {
  			$types = array($types);

  		}

  		$appTypes = self::getAppTypes($app);
  		foreach ($types as $type) {
  			if (array_search($type, $appTypes) !== false) {

  				return true;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * get the types of an app

  	 *

  	 * @param string $app
  	 * @return array
  	 */
  	private static function getAppTypes($app) {
  		//load the cache

  		if (count(self::$appTypes) == 0) {
  			self::$appTypes = OC_Appconfig::getValues(false, 'types');

  		}

  		if (isset(self::$appTypes[$app])) {

  			return explode(',', self::$appTypes[$app]);

  		} else {

  			return array();
  		}
  	}
  
  	/**
  	 * read app types from info.xml and cache them in the database
  	 */
  	public static function setAppTypes($app) {

  		$appData = self::getAppInfo($app);

  		if (isset($appData['types'])) {
  			$appTypes = implode(',', $appData['types']);
  		} else {
  			$appTypes = '';

  		}
  
  		OC_Appconfig::setValue($app, 'types', $appTypes);
  	}
  
  	/**
  	 * check if app is shipped

  	 *
  	 * @param string $appId the id of the app to check

  	 * @return bool
  	 *
  	 * Check if an app that is installed is a shipped app or installed from the appstore.
  	 */

  	public static function isShipped($appId) {
  		$info = self::getAppInfo($appId);
  		if (isset($info['shipped']) && $info['shipped'] == 'true') {

  			return true;
  		} else {
  			return false;
  		}
  	}
  
  	/**
  	 * get all enabled apps
  	 */

  	protected static $enabledAppsCache = array();
  
  	public static function getEnabledApps($forceRefresh = false) {
  		if (!OC_Config::getValue('installed', false)) {

  			return array();
  		}

  		if (!$forceRefresh && !empty(self::$enabledAppsCache)) {

  			return self::$enabledAppsCache;
  		}

  		$appConfig = \OC::$server->getAppConfig();
  		$appStatus = $appConfig->getValues(false, 'enabled');
  		$user = \OC_User::getUser();
  		foreach ($appStatus as $app => $enabled) {
  			if ($app === 'files') {
  				continue;
  			}
  			if ($enabled === 'yes') {
  				$apps[] = $app;
  			} else if ($enabled !== 'no') {
  				$groups = json_decode($enabled);
  				if (is_array($groups)) {
  					foreach ($groups as $group) {
  						if (\OC_Group::inGroup($user, $group)) {
  							$apps[] = $app;
  							break;
  						}
  					}
  				}

  			}
  		}

  		sort($apps);
  		array_unshift($apps, 'files');
  		// Only cache the app list, when the user is logged in.
  		// Otherwise we cache the list with disabled apps, although
  		// the apps are enabled for the user after he logged in.
  		if ($user) {
  			self::$enabledAppsCache = $apps;
  		}

  		return $apps;
  	}
  
  	/**

  	 * checks whether or not an app is enabled

  	 * @param string $app app
  	 * @return bool
  	 *
  	 * This function checks whether or not an app is enabled.
  	 */

  	public static function isEnabled($app) {
  		if ('files' == $app) {

  			return true;
  		}

  		$enabledApps = self::getEnabledApps();
  		return in_array($app, $enabledApps);

  	}
  
  	/**

  	 * enables an app

  	 * @param mixed $app app

  	 * @param array $groups (optional) when set, only these groups will have access to the app

  	 * @throws \Exception
  	 * @return void

  	 *
  	 * This function set an app as enabled in appconfig.
  	 */

  	public static function enable($app, $groups = null) {

  		self::$enabledAppsCache = array(); // flush

  		if (!OC_Installer::isInstalled($app)) {
  			$app = self::installApp($app);

  		}

  
  		if (!is_null($groups)) {
  			OC_Appconfig::setValue($app, 'enabled', json_encode($groups));

  		}else{

  			OC_Appconfig::setValue($app, 'enabled', 'yes');

  		}
  	}
  
  	/**

  	 * @param string $app
  	 * @return int
  	 */
  	public static function downloadApp($app) {
  		$appData=OC_OCSClient::getApplication($app);
  		$download=OC_OCSClient::getApplicationDownload($app, 1);
  		if(isset($download['downloadlink']) and $download['downloadlink']!='') {
  			// Replace spaces in download link without encoding entire URL
  			$download['downloadlink'] = str_replace(' ', '%20', $download['downloadlink']);
  			$info = array('source'=>'http', 'href'=>$download['downloadlink'], 'appdata'=>$appData);
  			$app=OC_Installer::installApp($info);
  		}
  		return $app;
  	}
  
  	/**
  	 * @param string $app

  	 * @return bool

  	 */
  	public static function removeApp($app) {
  		if (self::isShipped($app)) {
  			return false;
  		}
  
  		return OC_Installer::removeApp($app);
  	}
  
  	/**

  	 * This function set an app as disabled in appconfig.

  	 * @param string $app app

  	 */

  	public static function disable($app) {

  		self::$enabledAppsCache = array(); // flush

  		// check if app is a shipped app or not. if not delete
  		\OC_Hook::emit('OC_App', 'pre_disable', array('app' => $app));

  		OC_Appconfig::setValue($app, 'enabled', 'no' );

  	}
  
  	/**

  	 * adds an entry to the navigation

  	 * @param array $data array containing the data

  	 * @return bool
  	 *
  	 * This function adds a new entry to the navigation visible to users. $data
  	 * is an associative array.
  	 * The following keys are required:
  	 *   - id: unique id for this entry ('addressbook_index')
  	 *   - href: link to the page
  	 *   - name: Human readable name ('Addressbook')
  	 *
  	 * The following keys are optional:
  	 *   - icon: path to the icon of the app
  	 *   - order: integer, that influences the position of your application in
  	 *     the navigation. Lower values come first.
  	 */

  	public static function addNavigationEntry($data) {

  		OC::$server->getNavigationManager()->add($data);

  		return true;
  	}
  
  	/**

  	 * marks a navigation entry as active

  	 * @param string $id id of the entry
  	 * @return bool
  	 *
  	 * This function sets a navigation entry as active and removes the 'active'
  	 * property from all other entries. The templates can use this for
  	 * highlighting the current position of the user.
  	 */

  	public static function setActiveNavigationEntry($id) {

  		OC::$server->getNavigationManager()->setActiveEntry($id);

  		return true;
  	}
  
  	/**

  	 * Get the navigation entries for the $app

  	 * @param string $app app

  	 * @return array an array of the $data added with addNavigationEntry

  	 *
  	 * Warning: destroys the existing entries

  	 */
  	public static function getAppNavigationEntries($app) {

  		if (is_file(self::getAppPath($app) . '/appinfo/app.php')) {

  			OC::$server->getNavigationManager()->clear();

  			require $app . '/appinfo/app.php';

  			return OC::$server->getNavigationManager()->getAll();

  		}
  		return array();
  	}
  
  	/**

  	 * gets the active Menu entry

  	 * @return string id or empty string
  	 *
  	 * This function returns the id of the active navigation entry (set by
  	 * setActiveNavigationEntry
  	 */
  	public static function getActiveNavigationEntry() {

  		return OC::$server->getNavigationManager()->getActiveEntry();

  	}
  
  	/**

  	 * Returns the Settings Navigation
  	 * @return string

  	 *
  	 * This function returns an array containing all settings pages added. The
  	 * entries are sorted by the key 'order' ascending.
  	 */
  	public static function getSettingsNavigation() {

  		$l = OC_L10N::get('lib');

  
  		$settings = array();
  		// by default, settings only contain the help menu

  		if (OC_Util::getEditionString() === '' &&
  			OC_Config::getValue('knowledgebaseenabled', true) == true
  		) {

  			$settings = array(
  				array(
  					"id" => "help",
  					"order" => 1000,

  					"href" => OC_Helper::linkToRoute("settings_help"),

  					"name" => $l->t("Help"),

  					"icon" => OC_Helper::imagePath("settings", "help.svg")

  				)
  			);
  		}
  
  		// if the user is logged-in
  		if (OC_User::isLoggedIn()) {
  			// personal menu
  			$settings[] = array(
  				"id" => "personal",
  				"order" => 1,

  				"href" => OC_Helper::linkToRoute("settings_personal"),

  				"name" => $l->t("Personal"),

  				"icon" => OC_Helper::imagePath("settings", "personal.svg")

  			);
  
  			// if there are some settings forms

  			if (!empty(self::$settingsForms)) {

  				// settings menu

  				$settings[] = array(

  					"id" => "settings",
  					"order" => 1000,

  					"href" => OC_Helper::linkToRoute("settings_settings"),

  					"name" => $l->t("Settings"),

  					"icon" => OC_Helper::imagePath("settings", "settings.svg")

  				);
  			}
  
  			//SubAdmins are also allowed to access user management

  			if (OC_SubAdmin::isSubAdmin(OC_User::getUser())) {

  				// admin users menu
  				$settings[] = array(
  					"id" => "core_users",
  					"order" => 2,

  					"href" => OC_Helper::linkToRoute("settings_users"),

  					"name" => $l->t("Users"),

  					"icon" => OC_Helper::imagePath("settings", "users.svg")

  				);
  			}
  
  
  			// if the user is an admin

  			if (OC_User::isAdminUser(OC_User::getUser())) {

  				// admin settings

  				$settings[] = array(

  					"id" => "admin",
  					"order" => 1000,

  					"href" => OC_Helper::linkToRoute("settings_admin"),

  					"name" => $l->t("Admin"),

  					"icon" => OC_Helper::imagePath("settings", "admin.svg")

  				);
  			}
  		}
  
  		$navigation = self::proceedNavigation($settings);
  		return $navigation;
  	}

  	// This is private as well. It simply works, so don't ask for more details

  	private static function proceedNavigation($list) {
  		$activeApp = OC::$server->getNavigationManager()->getActiveEntry();
  		foreach ($list as &$navEntry) {
  			if ($navEntry['id'] == $activeApp) {
  				$navEntry['active'] = true;
  			} else {
  				$navEntry['active'] = false;

  			}

  		}
  		unset($navEntry);

  		usort($list, create_function('$a, $b', 'if( $a["order"] == $b["order"] ) {return 0;}elseif( $a["order"] < $b["order"] ) {return -1;}else{return 1;}'));

  
  		return $list;
  	}
  
  	/**
  	 * Get the path where to install apps

  	 *
  	 * @return string

  	 */
  	public static function getInstallPath() {

  		if (OC_Config::getValue('appstoreenabled', true) == false) {

  			return false;
  		}

  		foreach (OC::$APPSROOTS as $dir) {
  			if (isset($dir['writable']) && $dir['writable'] === true) {

  				return $dir['path'];
  			}
  		}
  
  		OC_Log::write('core', 'No application directories are marked as writable.', OC_Log::ERROR);
  		return null;
  	}

  	/**
  	 * search for an app in all app-directories
  	 * @param $appId
  	 * @return mixed (bool|string)
  	 */
  	protected static function findAppInDirectories($appId) {

  		static $app_dir = array();

  
  		if (isset($app_dir[$appId])) {
  			return $app_dir[$appId];

  		}

  
  		$possibleApps = array();

  		foreach(OC::$APPSROOTS as $dir) {

  			if(file_exists($dir['path'] . '/' . $appId)) {
  				$possibleApps[] = $dir;

  			}
  		}

  
  		if (empty($possibleApps)) {
  			return false;
  		} elseif(count($possibleApps) === 1) {
  			$dir = array_shift($possibleApps);
  			$app_dir[$appId] = $dir;
  			return $dir;
  		} else {
  			$versionToLoad = array();
  			foreach($possibleApps as $possibleApp) {
  				$version = self::getAppVersionByPath($possibleApp['path']);
  				if (empty($versionToLoad) || version_compare($version, $versionToLoad['version'], '>')) {
  					$versionToLoad = array(
  						'dir' => $possibleApp,
  						'version' => $version,
  					);
  				}
  			}
  			$app_dir[$appId] = $versionToLoad['dir'];
  			return $versionToLoad['dir'];
  			//TODO - write test
  		}

  	}

  	/**

  	 * Get the directory for the given app.
  	 * If the app is defined in multiple directories, the first one is taken. (false if not found)
  	 *
  	 * @param string $appId
  	 * @return string|false
  	 */
  	public static function getAppPath($appId) {
  		if ($appId === null || trim($appId) === '') {
  			return false;
  		}
  
  		if (($dir = self::findAppInDirectories($appId)) != false) {
  			return $dir['path'] . '/' . $appId;

  		}
  		return false;
  	}

  
  	/**
  	 * check if an app's directory is writable
  	 *
  	 * @param string $appId
  	 * @return bool
  	 */
  	public static function isAppDirWritable($appId) {
  		$path = self::getAppPath($appId);
  		return ($path !== false) ? is_writable($path) : false;
  	}

  	/**

  	 * Get the path for the given app on the access
  	 * If the app is defined in multiple directories, the first one is taken. (false if not found)
  	 *
  	 * @param string $appId
  	 * @return string|false
  	 */
  	public static function getAppWebPath($appId) {
  		if (($dir = self::findAppInDirectories($appId)) != false) {
  			return OC::$WEBROOT . $dir['url'] . '/' . $appId;

  		}
  		return false;
  	}
  
  	/**
  	 * get the last version of the app, either from appinfo/version or from appinfo/info.xml

  	 *
  	 * @param string $appId
  	 * @return string
  	 */
  	public static function getAppVersion($appId) {
  		$file = self::getAppPath($appId);
  		return ($file !== false) ? self::getAppVersionByPath($file) : '0';
  	}
  
  	/**
  	 * get app's version based on it's path
  	 * @param string $path
  	 * @return string

  	 */

  	public static function getAppVersionByPath($path) {
  		$versionFile = $path . '/appinfo/version';
  		$infoFile = $path . '/appinfo/info.xml';
  		if(is_file($versionFile)) {
  			return trim(file_get_contents($versionFile));

  		}else{

  			$appData = self::getAppInfo($infoFile, true);
  			return isset($appData['version']) ? $appData['version'] : '';

  		}
  	}

  	/**

  	 * Read all app metadata from the info.xml file
  	 *
  	 * @param string $appId id of the app or the path of the info.xml file

  	 * @param boolean $path (optional)

  	 * @return array|null

  	 * @note all data is read from info.xml, not just pre-defined fields

  	 */
  	public static function getAppInfo($appId, $path = false) {
  		if ($path) {
  			$file = $appId;
  		} else {
  			if (isset(self::$appInfo[$appId])) {
  				return self::$appInfo[$appId];

  			}

  			$file = self::getAppPath($appId) . '/appinfo/info.xml';
  		}
  		$data = array();
  		if (!file_exists($file)) {
  			return null;

  		}

  		$content = @file_get_contents($file);
  		if (!$content) {

  			return null;
  		}
  		$xml = new SimpleXMLElement($content);

  		$data['info'] = array();
  		$data['remote'] = array();
  		$data['public'] = array();
  		foreach ($xml->children() as $child) {

  			/**
  			 * @var $child SimpleXMLElement
  			 */

  			if ($child->getName() == 'remote') {
  				foreach ($child->children() as $remote) {

  					/**
  					 * @var $remote SimpleXMLElement
  					 */

  					$data['remote'][$remote->getName()] = (string)$remote;

  				}

  			} elseif ($child->getName() == 'public') {
  				foreach ($child->children() as $public) {

  					/**
  					 * @var $public SimpleXMLElement
  					 */

  					$data['public'][$public->getName()] = (string)$public;

  				}

  			} elseif ($child->getName() == 'types') {
  				$data['types'] = array();
  				foreach ($child->children() as $type) {

  					/**
  					 * @var $type SimpleXMLElement
  					 */

  					$data['types'][] = $type->getName();

  				}

  			} elseif ($child->getName() == 'description') {
  				$xml = (string)$child->asXML();
  				$data[$child->getName()] = substr($xml, 13, -14); //script <description> tags
  			} elseif ($child->getName() == 'documentation') {
  				foreach ($child as $subChild) {
  					$data["documentation"][$subChild->getName()] = (string)$subChild;

  				}

  			} else {
  				$data[$child->getName()] = (string)$child;

  			}
  		}

  		self::$appInfo[$appId] = $data;

  
  		return $data;
  	}
  
  	/**

  	 * Returns the navigation

  	 * @return array
  	 *
  	 * This function returns an array containing all entries added. The
  	 * entries are sorted by the key 'order' ascending. Additional to the keys
  	 * given for each app the following keys exist:
  	 *   - active: boolean, signals if the user is on this navigation entry
  	 */
  	public static function getNavigation() {

  		$entries = OC::$server->getNavigationManager()->getAll();

  		$navigation = self::proceedNavigation($entries);

  		return $navigation;
  	}
  
  	/**
  	 * get the id of loaded app

  	 *

  	 * @return string
  	 */
  	public static function getCurrentApp() {

  		$script = substr(OC_Request::scriptName(), strlen(OC::$WEBROOT) + 1);
  		$topFolder = substr($script, 0, strpos($script, '/'));

  		if (empty($topFolder)) {
  			$path_info = OC_Request::getPathInfo();
  			if ($path_info) {

  				$topFolder = substr($path_info, 1, strpos($path_info, '/', 1) - 1);

  			}
  		}

  		if ($topFolder == 'apps') {
  			$length = strlen($topFolder);
  			return substr($script, $length + 1, strpos($script, '/', $length + 1) - $length - 1);
  		} else {

  			return $topFolder;
  		}
  	}

  	/**
  	 * get the forms for either settings, admin or personal
  	 */
  	public static function getForms($type) {

  		$forms = array();
  		switch ($type) {

  			case 'settings':

  				$source = self::$settingsForms;

  				break;
  			case 'admin':

  				$source = self::$adminForms;

  				break;
  			case 'personal':

  				$source = self::$personalForms;

  				break;
  			default:
  				return array();
  		}

  		foreach ($source as $form) {
  			$forms[] = include $form;

  		}
  		return $forms;
  	}
  
  	/**
  	 * register a settings form to be shown
  	 */
  	public static function registerSettings($app, $page) {

  		self::$settingsForms[] = $app . '/' . $page . '.php';

  	}
  
  	/**
  	 * register an admin form to be shown

  	 *
  	 * @param string $app
  	 * @param string $page

  	 */
  	public static function registerAdmin($app, $page) {

  		self::$adminForms[] = $app . '/' . $page . '.php';

  	}
  
  	/**
  	 * register a personal form to be shown
  	 */
  	public static function registerPersonal($app, $page) {

  		self::$personalForms[] = $app . '/' . $page . '.php';

  	}
  
  	public static function registerLogIn($entry) {
  		self::$altLogin[] = $entry;
  	}
  
  	public static function getAlternativeLogIns() {
  		return self::$altLogin;
  	}
  
  	/**

  	 * get a list of all apps in the apps folder
  	 * @return array an array of app names (string IDs)

  	 * @todo: change the name of this method to getInstalledApps, which is more accurate
  	 */
  	public static function getAllApps() {

  		$apps = array();

  		foreach (OC::$APPSROOTS as $apps_dir) {
  			if (!is_readable($apps_dir['path'])) {
  				OC_Log::write('core', 'unable to read app folder : ' . $apps_dir['path'], OC_Log::WARN);

  				continue;
  			}

  			$dh = opendir($apps_dir['path']);

  			if (is_resource($dh)) {

  				while (($file = readdir($dh)) !== false) {

  					if ($file[0] != '.' and is_file($apps_dir['path'] . '/' . $file . '/appinfo/app.php')) {

  
  						$apps[] = $file;
  
  					}
  
  				}
  			}
  
  		}
  
  		return $apps;
  	}
  
  	/**

  	 * Lists all apps, this is used in apps.php

  	 * @return array
  	 */
  	public static function listAllApps() {
  		$installedApps = OC_App::getAllApps();
  
  		//TODO which apps do we want to blacklist and how do we integrate
  		// blacklisting with the multi apps folder feature?

  		$blacklist = array('files'); //we don't want to show configuration for these

  		$appList = array();

  		foreach ($installedApps as $app) {
  			if (array_search($app, $blacklist) === false) {

  				$info = OC_App::getAppInfo($app);

  
  				if (!isset($info['name'])) {

  					OC_Log::write('core', 'App id "' . $app . '" has no name in appinfo', OC_Log::ERROR);

  					continue;
  				}

  				$enabled = OC_Appconfig::getValue($app, 'enabled', 'no');
  				$info['groups'] = null;
  				if ($enabled === 'yes') {

  					$active = true;

  				} else if($enabled === 'no') {

  					$active = false;

  				} else {
  					$active = true;
  					$info['groups'] = $enabled;

  				}
  
  				$info['active'] = $active;

  				if(isset($info['shipped']) and ($info['shipped'] == 'true')) {
  					$info['internal'] = true;
  					$info['internallabel'] = 'Internal App';
  					$info['internalclass'] = '';
  					$info['removable'] = false;

  				} else {

  					$info['internal'] = false;
  					$info['internallabel'] = '3rd Party';
  					$info['internalclass'] = 'externalapp';
  					$info['removable'] = true;

  				}

  				$info['update'] = OC_Installer::isUpdateAvailable($app);

  				$info['preview'] = OC_Helper::imagePath('settings', 'trans.png');
  				$info['version'] = OC_App::getAppVersion($app);
  				$appList[] = $info;
  			}
  		}
  		$remoteApps = OC_App::getAppstoreApps();

  		if ($remoteApps) {

  			// Remove duplicates

  			foreach ($appList as $app) {
  				foreach ($remoteApps AS $key => $remote) {
  					if ($app['name'] === $remote['name'] ||
  						$app['ocsid'] ===  $remote['id']) {
  						unset($remoteApps[$key]);

  					}
  				}
  			}

  			$combinedApps = array_merge($appList, $remoteApps);

  		} else {
  			$combinedApps = $appList;
  		}

  		// bring the apps into the right order with a custom sort function
  		usort($combinedApps, function ($a, $b) {

  			// priority 1: active
  			if ($a['active'] != $b['active']) {
  				return $b['active'] - $a['active'];
  			}

  			// priority 2: shipped
  			$aShipped = (array_key_exists('shipped', $a) && $a['shipped'] === 'true') ? 1 : 0;
  			$bShipped = (array_key_exists('shipped', $b) && $b['shipped'] === 'true') ? 1 : 0;
  			if ($aShipped !== $bShipped) {
  				return ($bShipped - $aShipped);
  			}

  			// priority 3: recommended
  			if ($a['internalclass'] != $b['internalclass']) {
  				$aTemp = ($a['internalclass'] == 'recommendedapp' ? 1 : 0);
  				$bTemp = ($b['internalclass'] == 'recommendedapp' ? 1 : 0);
  				return ($bTemp - $aTemp);
  			}

  			// priority 4: alphabetical
  			return strcasecmp($a['name'], $b['name']);

  		});

  		return $combinedApps;

  	}
  
  	/**

  	 * get a list of all apps on apps.owncloud.com

  	 * @return array, multi-dimensional array of apps.
  	 *     Keys: id, name, type, typename, personid, license, detailpage, preview, changed, description
  	 */

  	public static function getAppstoreApps($filter = 'approved') {

  		$categoryNames = OC_OCSClient::getCategories();

  		if (is_array($categoryNames)) {

  			// Check that categories of apps were retrieved correctly

  			if (!$categories = array_keys($categoryNames)) {

  				return false;
  			}
  
  			$page = 0;

  			$remoteApps = OC_OCSClient::getApplications($categories, $page, $filter);

  			$app1 = array();
  			$i = 0;

  			foreach ($remoteApps as $app) {

  				$app1[$i] = $app;
  				$app1[$i]['author'] = $app['personid'];
  				$app1[$i]['ocs_id'] = $app['id'];
  				$app1[$i]['internal'] = $app1[$i]['active'] = 0;
  				$app1[$i]['update'] = false;

  				$app1[$i]['groups'] = false;
  				$app1[$i]['removable'] = false;
  				if ($app['label'] == 'recommended') {

  					$app1[$i]['internallabel'] = 'Recommended';
  					$app1[$i]['internalclass'] = 'recommendedapp';

  				} else {

  					$app1[$i]['internallabel'] = '3rd Party';
  					$app1[$i]['internalclass'] = 'externalapp';
  				}
  
  
  				// rating img

  				if ($app['score'] < 5) {
  					$img = OC_Helper::imagePath( "core", "rating/s1.png" );
  				} elseif ($app['score'] < 15) {
  					$img = OC_Helper::imagePath( "core", "rating/s2.png" );
  				} elseif($app['score'] < 25) {
  					$img = OC_Helper::imagePath( "core", "rating/s3.png" );
  				} elseif($app['score'] < 35) {
  					$img = OC_Helper::imagePath( "core", "rating/s4.png" );
  				} elseif($app['score'] < 45) {
  					$img = OC_Helper::imagePath( "core", "rating/s5.png" );
  				} elseif($app['score'] < 55) {
  					$img = OC_Helper::imagePath( "core", "rating/s6.png" );
  				} elseif($app['score'] < 65) {
  					$img = OC_Helper::imagePath( "core", "rating/s7.png" );
  				} elseif($app['score'] < 75) {
  					$img = OC_Helper::imagePath( "core", "rating/s8.png" );
  				} elseif($app['score'] < 85) {
  					$img = OC_Helper::imagePath( "core", "rating/s9.png" );
  				} elseif($app['score'] < 95) {
  					$img = OC_Helper::imagePath( "core", "rating/s10.png" );
  				} elseif($app['score'] < 100) {
  					$img = OC_Helper::imagePath( "core", "rating/s11.png" );
  				}
  
  				$app1[$i]['score'] = '<img src="' . $img . '"> Score: ' . $app['score'] . '%';

  				$i++;
  			}
  		}

  		if (empty($app1)) {

  			return false;
  		} else {
  			return $app1;
  		}
  	}

  	public static function shouldUpgrade($app) {
  		$versions = self::getAppVersions();
  		$currentVersion = OC_App::getAppVersion($app);
  		if ($currentVersion) {
  			$installedVersion = $versions[$app];
  			if (version_compare($currentVersion, $installedVersion, '>')) {
  				return true;
  			}
  		}
  		return false;
  	}

  	/**

  	 * check if the app needs updating and update when needed

  	 *
  	 * @param string $app

  	 */
  	public static function checkUpgrade($app) {
  		if (in_array($app, self::$checkedApps)) {
  			return;
  		}
  		self::$checkedApps[] = $app;

  		if (!self::shouldUpgrade($app)) {
  			return;
  		}

  		$versions = self::getAppVersions();

  		$installedVersion = $versions[$app];
  		$currentVersion = OC_App::getAppVersion($app);
  		OC_Log::write(
  			$app,
  			'starting app upgrade from ' . $installedVersion . ' to ' . $currentVersion,
  			OC_Log::DEBUG
  		);
  		$info = self::getAppInfo($app);
  		try {
  			OC_App::updateApp($app);
  			OC_Hook::emit('update', 'success', 'Updated ' . $info['name'] . ' app');
  		} catch (Exception $e) {
  			OC_Hook::emit('update', 'failure', 'Failed to update ' . $info['name'] . ' app: ' . $e->getMessage());
  			$l = OC_L10N::get('lib');
  			throw new RuntimeException($l->t('Failed to upgrade "%s".', array($app)), 0, $e);

  		}

  		OC_Appconfig::setValue($app, 'installed_version', OC_App::getAppVersion($app));

  	}
  
  	/**
  	 * check if the current enabled apps are compatible with the current
  	 * ownCloud version. disable them if not.
  	 * This is important if you upgrade ownCloud and have non ported 3rd
  	 * party apps installed.

  	 *
  	 * @param array $apps optional app id list to check, uses all enabled apps
  	 * when not specified
  	 *
  	 * @return array containing the list of ids of the disabled apps

  	 */
  	public static function checkAppsRequirements($apps = array()) {

  		$disabledApps = array();

  		if (empty($apps)) {
  			$apps = OC_App::getEnabledApps();
  		}
  		$version = OC_Util::getVersion();

  		foreach ($apps as $app) {

  			// check if the app is compatible with this version of ownCloud
  			$info = OC_App::getAppInfo($app);

  			if(!self::isAppCompatible($version, $info)) {

  				OC_Log::write('core',

  					'App "' . $info['name'] . '" (' . $app . ') can\'t be used because it is'
  					. ' not compatible with this version of ownCloud',

  					OC_Log::ERROR);

  				OC_App::disable($app);
  				OC_Hook::emit('update', 'success', 'Disabled ' . $info['name'] . ' app because it is not compatible');
  				$disabledApps[] = $app;

  			}
  		}

  		return $disabledApps;

  	}

  	/**
  	 * Adjust the number of version parts of $version1 to match
  	 * the number of version parts of $version2.
  	 *
  	 * @param string $version1 version to adjust
  	 * @param string $version2 version to take the number of parts from
  	 * @return string shortened $version1
  	 */
  	private static function adjustVersionParts($version1, $version2) {
  		$version1 = explode('.', $version1);
  		$version2 = explode('.', $version2);
  		// reduce $version1 to match the number of parts in $version2
  		while (count($version1) > count($version2)) {
  			array_pop($version1);
  		}
  		// if $version1 does not have enough parts, add some
  		while (count($version1) < count($version2)) {
  			$version1[] = '0';
  		}
  		return implode('.', $version1);
  	}

  
  	/**

  	 * Check whether the current ownCloud version matches the given
  	 * application's version requirements.
  	 *
  	 * The comparison is made based on the number of parts that the
  	 * app info version has. For example for ownCloud 6.0.3 if the
  	 * app info version is expecting version 6.0, the comparison is
  	 * made on the first two parts of the ownCloud version.
  	 * This means that it's possible to specify "requiremin" => 6
  	 * and "requiremax" => 6 and it will still match ownCloud 6.0.3.
  	 *
  	 * @param string $ocVersion ownCloud version to check against
  	 * @param array  $appInfo app info (from xml)
  	 *

  	 * @return boolean true if compatible, otherwise false
  	 */

  	public static function isAppCompatible($ocVersion, $appInfo){
  		$requireMin = '';
  		$requireMax = '';
  		if (isset($appInfo['requiremin'])) {
  			$requireMin = $appInfo['requiremin'];
  		} else if (isset($appInfo['require'])) {
  			$requireMin = $appInfo['require'];
  		}

  		if (isset($appInfo['requiremax'])) {
  			$requireMax = $appInfo['requiremax'];
  		}

  		if (is_array($ocVersion)) {
  			$ocVersion = implode('.', $ocVersion);
  		}

  		if (!empty($requireMin)
  			&& version_compare(self::adjustVersionParts($ocVersion, $requireMin), $requireMin, '<')
  		) {
  
  			return false;
  		}
  
  		if (!empty($requireMax)
  			&& version_compare(self::adjustVersionParts($ocVersion, $requireMax), $requireMax, '>')
  		) {
  
  			return false;

  		}
  
  		return true;
  	}

  	/**
  	 * get the installed version of all apps
  	 */
  	public static function getAppVersions() {
  		static $versions;

  		if (isset($versions)) { // simple cache, needs to be fixed

  			return $versions; // when function is used besides in checkUpgrade
  		}

  		$versions = array();
  		$query = OC_DB::prepare('SELECT `appid`, `configvalue` FROM `*PREFIX*appconfig`'
  			. ' WHERE `configkey` = \'installed_version\'');

  		$result = $query->execute();

  		while ($row = $result->fetchRow()) {
  			$versions[$row['appid']] = $row['configvalue'];

  		}
  		return $versions;
  	}

  
  	/**
  	 * @param mixed $app
  	 * @return bool
  	 * @throws Exception if app is not compatible with this version of ownCloud
  	 * @throws Exception if no app-name was specified
  	 */
  	public static function installApp($app) {
  		$l = OC_L10N::get('core');
  		$appData=OC_OCSClient::getApplication($app);
  
  		// check if app is a shipped app or not. OCS apps have an integer as id, shipped apps use a string
  		if(!is_numeric($app)) {
  			$shippedVersion=self::getAppVersion($app);
  			if($appData && version_compare($shippedVersion, $appData['version'], '<')) {
  				$app = self::downloadApp($app);
  			} else {
  				$app = OC_Installer::installShippedApp($app);
  			}
  		}else{
  			$app = self::downloadApp($app);
  		}
  
  		if($app!==false) {
  			// check if the app is compatible with this version of ownCloud
  			$info = self::getAppInfo($app);
  			$version=OC_Util::getVersion();
  			if(!self::isAppCompatible($version, $info)) {
  				throw new \Exception(
  					$l->t('App \"%s\" can\'t be installed because it is not compatible with this version of ownCloud.',
  						array($info['name'])
  					)
  				);
  			}else{
  				OC_Appconfig::setValue( $app, 'enabled', 'yes' );
  				if(isset($appData['id'])) {
  					OC_Appconfig::setValue( $app, 'ocsid', $appData['id'] );
  				}
  				\OC_Hook::emit('OC_App', 'post_enable', array('app' => $app));
  			}
  		}else{
  			throw new \Exception($l->t("No app name specified"));
  		}
  
  		return $app;
  	}

  	/**
  	 * update the database for the app and call the update script

  	 *
  	 * @param string $appId
  	 * @return bool

  	 */

  	public static function updateApp($appId) {
  		if (file_exists(self::getAppPath($appId) . '/appinfo/preupdate.php')) {
  			self::loadApp($appId);
  			include self::getAppPath($appId) . '/appinfo/preupdate.php';

  		}

  		if (file_exists(self::getAppPath($appId) . '/appinfo/database.xml')) {
  			OC_DB::updateDbFromStructure(self::getAppPath($appId) . '/appinfo/database.xml');

  		}

  		if (!self::isEnabled($appId)) {
  			return false;

  		}

  		if (file_exists(self::getAppPath($appId) . '/appinfo/update.php')) {
  			self::loadApp($appId);
  			include self::getAppPath($appId) . '/appinfo/update.php';

  		}
  
  		//set remote/public handlers

  		$appData = self::getAppInfo($appId);
  		if (array_key_exists('ocsid', $appData)) {
  			OC_Appconfig::setValue($appId, 'ocsid', $appData['ocsid']);

  		}

  		foreach ($appData['remote'] as $name => $path) {
  			OCP\CONFIG::setAppValue('core', 'remote_' . $name, $appId . '/' . $path);

  		}

  		foreach ($appData['public'] as $name => $path) {
  			OCP\CONFIG::setAppValue('core', 'public_' . $name, $appId . '/' . $path);
  		}
  
  		self::setAppTypes($appId);

  		return true;

  	}
  
  	/**

  	 * @param string $appId

  	 * @return \OC\Files\View
  	 */

  	public static function getStorage($appId) {
  		if (OC_App::isEnabled($appId)) { //sanity check
  			if (OC_User::isLoggedIn()) {
  				$view = new \OC\Files\View('/' . OC_User::getUser());
  				if (!$view->file_exists($appId)) {
  					$view->mkdir($appId);

  				}

  				return new \OC\Files\View('/' . OC_User::getUser() . '/' . $appId);
  			} else {
  				OC_Log::write('core', 'Can\'t get app storage, app ' . $appId . ', user not logged in', OC_Log::ERROR);

  				return false;
  			}

  		} else {
  			OC_Log::write('core', 'Can\'t get app storage, app ' . $appId . ' not enabled', OC_Log::ERROR);

  			return false;
  		}
  	}
  }