<?php
  
  /**
  * ownCloud
  *
  * @author Frank Karlitschek
  * @copyright 2012 Frank Karlitschek frank@owncloud.org
  *
  * 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/>.
  *
  */
  
  /**
   * error code for functions not provided by the group backend
   */
  define('OC_GROUP_BACKEND_NOT_IMPLEMENTED',   -501);
  
  /**
   * actions that user backends can define
   */
  define('OC_GROUP_BACKEND_CREATE_GROUP',      0x00000001);
  define('OC_GROUP_BACKEND_DELETE_GROUP',      0x00000010);
  define('OC_GROUP_BACKEND_ADD_TO_GROUP',      0x00000100);
  define('OC_GROUP_BACKEND_REMOVE_FROM_GOUP',  0x00001000);

  define('OC_GROUP_BACKEND_GET_DISPLAYNAME',   0x00010000); //OBSOLETE

  define('OC_GROUP_BACKEND_COUNT_USERS',       0x00100000);

  
  /**
   * Abstract base class for user management
   */
  abstract class OC_Group_Backend implements OC_Group_Interface {
  	protected $possibleActions = array(
  		OC_GROUP_BACKEND_CREATE_GROUP => 'createGroup',
  		OC_GROUP_BACKEND_DELETE_GROUP => 'deleteGroup',
  		OC_GROUP_BACKEND_ADD_TO_GROUP => 'addToGroup',
  		OC_GROUP_BACKEND_REMOVE_FROM_GOUP => 'removeFromGroup',

  		OC_GROUP_BACKEND_COUNT_USERS => 'countUsersInGroup',

  	);
  
  	/**

  	* Get all supported actions

  	* @return int bitwise-or'ed actions
  	*
  	* Returns the supported actions as int to be
  	* compared with OC_USER_BACKEND_CREATE_USER etc.
  	*/
  	public function getSupportedActions() {
  		$actions = 0;
  		foreach($this->possibleActions AS $action => $methodName) {
  			if(method_exists($this, $methodName)) {
  				$actions |= $action;
  			}
  		}
  
  		return $actions;
  	}
  
  	/**

  	* Check if backend implements actions

  	* @param int $actions bitwise-or'ed actions

  	* @return bool

  	*
  	* Returns the supported actions as int to be
  	* compared with OC_GROUP_BACKEND_CREATE_GROUP etc.
  	*/
  	public function implementsActions($actions) {
  		return (bool)($this->getSupportedActions() & $actions);
  	}
  
  	/**

  	 * is user in group?

  	 * @param string $uid uid of the user
  	 * @param string $gid gid of the group
  	 * @return bool
  	 *
  	 * Checks whether the user is member of a group or not.
  	 */
  	public function inGroup($uid, $gid) {
  		return in_array($gid, $this->getUserGroups($uid));
  	}
  
  	/**

  	 * Get all groups a user belongs to

  	 * @param string $uid Name of the user

  	 * @return array an array of 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) {
  		return array();
  	}
  
  	/**

  	 * get a list of all groups

  	 * @param string $search
  	 * @param int $limit
  	 * @param int $offset

  	 * @return array an array of group names

  	 *
  	 * Returns a list with all groups
  	 */
  
  	public function getGroups($search = '', $limit = -1, $offset = 0) {
  		return array();
  	}
  
  	/**
  	 * check if a group exists
  	 * @param string $gid
  	 * @return bool
  	 */
  	public function groupExists($gid) {
  		return in_array($gid, $this->getGroups($gid, 1));
  	}
  
  	/**

  	 * get a list of all users in a group

  	 * @param string $gid
  	 * @param string $search
  	 * @param int $limit
  	 * @param int $offset

  	 * @return array an array of user ids

  	 */
  	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
  		return array();
  	}

  }