<?php
  
  /**
   * ownCloud
   *
   * @author Artuhr Schiwon
   * @copyright 2013 Arthur Schiwon blizzz@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/>.
   *
   */
  
  namespace OCA\user_ldap;
  
  class Group_Proxy extends lib\Proxy implements \OCP\GroupInterface {
  	private $backends = array();
  	private $refBackend = null;
  
  	/**
  	 * @brief Constructor
  	 * @param $serverConfigPrefixes array containing the config Prefixes
  	 */
  	public function __construct($serverConfigPrefixes) {
  		parent::__construct();
  		foreach($serverConfigPrefixes as $configPrefix) {
  		    $this->backends[$configPrefix] = new \OCA\user_ldap\GROUP_LDAP();
  		    $connector = $this->getConnector($configPrefix);
  			$this->backends[$configPrefix]->setConnector($connector);
  			if(is_null($this->refBackend)) {
  				$this->refBackend = &$this->backends[$configPrefix];
  			}
  		}
  	}
  
  	/**
  	 * @brief Tries the backends one after the other until a positive result is returned from the specified method
  	 * @param $gid string, the gid connected to the request
  	 * @param $method string, the method of the group backend that shall be called
  	 * @param $parameters an array of parameters to be passed
  	 * @return mixed, the result of the method or false
  	 */
  	protected function walkBackends($gid, $method, $parameters) {
  		$cacheKey = $this->getGroupCacheKey($gid);
  		foreach($this->backends as $configPrefix => $backend) {
  		    if($result = call_user_func_array(array($backend, $method), $parameters)) {
  				$this->writeToCache($cacheKey, $configPrefix);
  				return $result;
  		    }
  		}
  		return false;
  	}
  
  	/**
  	 * @brief Asks the backend connected to the server that supposely takes care of the gid from the request.
  	 * @param $gid string, the gid connected to the request
  	 * @param $method string, the method of the group backend that shall be called
  	 * @param $parameters an array of parameters to be passed
  	 * @return mixed, the result of the method or false
  	 */
  	protected function callOnLastSeenOn($gid, $method, $parameters) {
  		$cacheKey = $this->getGroupCacheKey($gid);;
  		$prefix = $this->getFromCache($cacheKey);
  		//in case the uid has been found in the past, try this stored connection first
  		if(!is_null($prefix)) {
  			if(isset($this->backends[$prefix])) {
  				$result = call_user_func_array(array($this->backends[$prefix], $method), $parameters);
  				if(!$result) {
  					//not found here, reset cache to null if group vanished
  					//because sometimes methods return false with a reason
  					$groupExists = call_user_func_array(
  						array($this->backends[$prefix], 'groupExists'),
  						array($gid)
  					);
  					if(!$groupExists) {
  						$this->writeToCache($cacheKey, null);
  					}
  				}
  				return $result;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * @brief is user in group?
  	 * @param $uid uid of the user
  	 * @param $gid gid of the group
  	 * @returns true/false
  	 *
  	 * Checks whether the user is member of a group or not.
  	 */
  	public function inGroup($uid, $gid) {
  		return $this->handleRequest($gid, 'inGroup', array($uid, $gid));
  	}
  
  	/**
  	 * @brief Get all groups a user belongs to
  	 * @param $uid Name of the user
  	 * @returns array with group names
  	 *
  	 * This function fetches all groups a user belongs to. It does not check
  	 * if the user exists at all.
  	 */
  	public function getUserGroups($uid) {
  		$groups = array();
  
  		foreach($this->backends as $backend) {
  		    $backendGroups = $backend->getUserGroups($uid);
  			if (is_array($backendGroups)) {
  				$groups = array_merge($groups, $backendGroups);
  			}
  		}
  
  		return $groups;
  	}
  
  	/**
  	 * @brief get a list of all users in a group
  	 * @returns array with user ids
  	 */
  	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
  		$users = array();
  
  		foreach($this->backends as $backend) {
  		    $backendUsers = $backend->usersInGroup($gid, $search, $limit, $offset);
  			if (is_array($backendUsers)) {
  				$users = array_merge($users, $backendUsers);
  			}
  		}
  
  		return $users;
  	}
  
  	/**
  	 * @brief get a list of all display names in a group
  	 * @returns array with display names (value) and user ids(key)
  	 */
  	public function displayNamesInGroup($gid, $search, $limit, $offset) {
  		$displayNames = array();
  
  		foreach($this->backends as $backend) {
  			$backendUsers = $backend->displayNamesInGroup($gid, $search, $limit, $offset);
  			if (is_array($backendUsers)) {
  				$displayNames = array_merge($displayNames, $backendUsers);
  			}
  		}
  		return $displayNames;
  	}
  
  	/**
  	 * @brief get a list of all groups
  	 * @returns array with group names
  	 *
  	 * Returns a list with all groups
  	 */
  	public function getGroups($search = '', $limit = -1, $offset = 0) {
  		$groups = array();
  
  		foreach($this->backends as $backend) {
  		    $backendGroups = $backend->getGroups($search, $limit, $offset);
  			if (is_array($backendGroups)) {
  				$groups = array_merge($groups, $backendGroups);
  			}
  		}
  
  		return $groups;
  	}
  
  	/**
  	 * check if a group exists
  	 * @param string $gid
  	 * @return bool
  	 */
  	public function groupExists($gid) {
  		return $this->handleRequest($gid, 'groupExists', array($gid));
  	}
  
  	/**
  	 * @brief Check if backend implements actions
  	 * @param $actions bitwise-or'ed actions
  	 * @returns boolean
  	 *
  	 * Returns the supported actions as int to be
  	 * compared with OC_USER_BACKEND_CREATE_USER etc.
  	 */
  	public function implementsActions($actions) {
  		//it's the same across all our user backends obviously
  		return $this->refBackend->implementsActions($actions);
  	}
  }