<?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;

  use OCA\user_ldap\lib\ILDAPWrapper;

  class User_Proxy extends lib\Proxy implements \OCP\UserInterface {
  	private $backends = array();
  	private $refBackend = null;
  
  	/**
  	 * @brief Constructor
  	 * @param $serverConfigPrefixes array containing the config Prefixes
  	 */

  	public function __construct($serverConfigPrefixes, ILDAPWrapper $ldap) {
  		parent::__construct($ldap);

  		foreach($serverConfigPrefixes as $configPrefix) {

  		    $this->backends[$configPrefix] =
  				new \OCA\user_ldap\USER_LDAP($this->getAccess($configPrefix));

  			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 $uid string, the uid connected to the request
  	 * @param $method string, the method of the user backend that shall be called
  	 * @param $parameters an array of parameters to be passed
  	 * @return mixed, the result of the method or false
  	 */
  	protected  function walkBackends($uid, $method, $parameters) {
  		$cacheKey = $this->getUserCacheKey($uid);
  		foreach($this->backends as $configPrefix => $backend) {

  			$instance = $backend;
  			if(!method_exists($instance, $method)
  				&& method_exists($this->getAccess($configPrefix), $method)) {
  				$instance = $this->getAccess($configPrefix);
  			}
  			if($result = call_user_func_array(array($instance, $method), $parameters)) {

  				$this->writeToCache($cacheKey, $configPrefix);
  				return $result;

  			}

  		}
  		return false;
  	}
  
  	/**
  	 * @brief Asks the backend connected to the server that supposely takes care of the uid from the request.
  	 * @param $uid string, the uid connected to the request
  	 * @param $method string, the method of the user backend that shall be called
  	 * @param $parameters an array of parameters to be passed

  	 * @param $passOnWhen the result matches this variable

  	 * @return mixed, the result of the method or false
  	 */

  	protected  function callOnLastSeenOn($uid, $method, $parameters, $passOnWhen) {

  		$cacheKey = $this->getUserCacheKey($uid);
  		$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])) {

  				$instance = $this->backends[$prefix];
  				if(!method_exists($instance, $method)
  					&& method_exists($this->getAccess($prefix), $method)) {
  					$instance = $this->getAccess($prefix);
  				}
  				$result = call_user_func_array(array($instance, $method), $parameters);

  				if($result === $passOnWhen) {

  					//not found here, reset cache to null if user vanished
  					//because sometimes methods return false with a reason
  					$userExists = call_user_func_array(
  						array($this->backends[$prefix], 'userExists'),
  						array($uid)
  					);
  					if(!$userExists) {
  						$this->writeToCache($cacheKey, null);
  					}
  				}
  				return $result;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * @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);
  	}
  
  	/**
  	 * @brief Get a list of all users
  	 * @returns array with all uids
  	 *
  	 * Get a list of all users.
  	 */
  	public function getUsers($search = '', $limit = 10, $offset = 0) {
  		//we do it just as the /OC_User implementation: do not play around with limit and offset but ask all backends
  		$users = array();
  		foreach($this->backends as $backend) {
  			$backendUsers = $backend->getUsers($search, $limit, $offset);
  			if (is_array($backendUsers)) {
  				$users = array_merge($users, $backendUsers);
  			}
  		}
  		return $users;
  	}
  
  	/**
  	 * @brief check if a user exists
  	 * @param string $uid the username
  	 * @return boolean
  	 */
  	public function userExists($uid) {
  		return $this->handleRequest($uid, 'userExists', array($uid));
  	}
  
  	/**
  	 * @brief Check if the password is correct
  	 * @param $uid The username
  	 * @param $password The password
  	 * @returns true/false
  	 *
  	 * Check if the password is correct without logging in the user
  	 */
  	public function checkPassword($uid, $password) {
  		return $this->handleRequest($uid, 'checkPassword', array($uid, $password));
  	}
  
  	/**
  	 * @brief get the user's home directory
  	 * @param string $uid the username
  	 * @return boolean
  	 */
  	public function getHome($uid) {
  		return $this->handleRequest($uid, 'getHome', array($uid));
  	}
  
  	/**
  	 * @brief get display name of the user
  	 * @param $uid user ID of the user
  	 * @return display name
  	 */
  	public function getDisplayName($uid) {
  		return $this->handleRequest($uid, 'getDisplayName', array($uid));
  	}
  
  	/**

  	 * @brief checks whether the user is allowed to change his avatar in ownCloud
  	 * @param $uid string the ownCloud user name
  	 * @return boolean either the user can or cannot
  	 */
  	public function canChangeAvatar($uid) {
  		return $this->handleRequest($uid, 'canChangeAvatar', array($uid), true);
  	}
  
  	/**

  	 * @brief Get a list of all display names
  	 * @returns array with  all displayNames (value) and the corresponding uids (key)
  	 *
  	 * Get a list of all display names and user ids.
  	 */
  	public function getDisplayNames($search = '', $limit = null, $offset = null) {
  		//we do it just as the /OC_User implementation: do not play around with limit and offset but ask all backends
  		$users = array();
  		foreach($this->backends as $backend) {
  			$backendUsers = $backend->getDisplayNames($search, $limit, $offset);
  			if (is_array($backendUsers)) {
  				$users = $users + $backendUsers;
  			}
  		}
  		return $users;
  	}
  
  	/**
  	 * @brief delete a user
  	 * @param $uid The username of the user to delete
  	 * @returns true/false
  	 *
  	 * Deletes a user
  	 */
  	public function deleteUser($uid) {
  		return false;
  	}
  
  	/**
  	 * @return bool
  	 */
  	public function hasUserListings() {
  		return $this->refBackend->hasUserListings();
  	}

  	/**
  	 * @brief Count the number of users
  	 * @returns int | bool
  	 */
  	public function countUsers() {
  		$users = false;
  		foreach($this->backends as $backend) {
  			$backendUsers = $backend->countUsers();
  			if ($backendUsers !== false) {
  				$users += $backendUsers;
  			}
  		}
  		return $users;
  	}

  }