<?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/>.
   *
   */
  
  /**
   * This class provides all methods needed for managing groups.
   *
   * Hooks provided:
   *   pre_createGroup(&run, gid)
   *   post_createGroup(gid)
   *   pre_deleteGroup(&run, gid)
   *   post_deleteGroup(gid)
   *   pre_addToGroup(&run, uid, gid)
   *   post_addToGroup(uid, gid)
   *   pre_removeFromGroup(&run, uid, gid)
   *   post_removeFromGroup(uid, gid)
   */
  class OC_Group {

  	/**

  	 * @var \OC\Group\Manager $manager

  	 */

  	private static $manager;
  
  	/**
  	 * @var \OC\User\Manager
  	 */
  	private static $userManager;
  
  	/**
  	 * @return \OC\Group\Manager
  	 */
  	public static function getManager() {
  		if (self::$manager) {
  			return self::$manager;
  		}
  		self::$userManager = \OC_User::getManager();
  		self::$manager = new \OC\Group\Manager(self::$userManager);
  		return self::$manager;
  	}

  
  	/**

  	 * set the group backend
  	 * @param \OC_Group_Backend $backend  The backend to use for user managment

  	 * @return bool
  	 */

  	public static function useBackend($backend) {
  		self::getManager()->addBackend($backend);
  		return true;

  	}
  
  	/**
  	 * remove all used backends
  	 */
  	public static function clearBackends() {

  		self::getManager()->clearBackends();

  	}
  
  	/**

  	 * Try to create a new group

  	 * @param string $gid The name of the group to create
  	 * @return bool
  	 *
  	 * Tries to create a new group. If the group name already exists, false will
  	 * be returned. Basic checking of Group name
  	 */

  	public static function createGroup($gid) {
  		OC_Hook::emit("OC_Group", "pre_createGroup", array("run" => true, "gid" => $gid));

  		if (self::getManager()->createGroup($gid)) {
  			OC_Hook::emit("OC_User", "post_createGroup", array("gid" => $gid));
  			return true;
  		} else {

  			return false;
  		}
  	}
  
  	/**

  	 * delete a group

  	 * @param string $gid gid of the group to delete
  	 * @return bool
  	 *
  	 * Deletes a group and removes it from the group_user-table
  	 */

  	public static function deleteGroup($gid) {

  		// Prevent users from deleting group admin

  		if ($gid == "admin") {

  			return false;
  		}

  		OC_Hook::emit("OC_Group", "pre_deleteGroup", array("run" => true, "gid" => $gid));

  		$group = self::getManager()->get($gid);
  		if ($group) {
  			if ($group->delete()) {
  				OC_Hook::emit("OC_User", "post_deleteGroup", array("gid" => $gid));

  				return true;
  			}

  		}

  		return false;

  	}
  
  	/**

  	 * 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 static function inGroup($uid, $gid) {
  		$group = self::getManager()->get($gid);
  		$user = self::$userManager->get($uid);
  		if ($group and $user) {
  			return $group->inGroup($user);

  		}
  		return false;
  	}
  
  	/**

  	 * Add a user to a group

  	 * @param string $uid Name of the user to add to group
  	 * @param string $gid Name of the group in which add the user
  	 * @return bool
  	 *
  	 * Adds a user to a group.
  	 */

  	public static function addToGroup($uid, $gid) {
  		$group = self::getManager()->get($gid);
  		$user = self::$userManager->get($uid);
  		if ($group and $user) {
  			OC_Hook::emit("OC_Group", "pre_addToGroup", array("run" => true, "uid" => $uid, "gid" => $gid));
  			$group->addUser($user);
  			OC_Hook::emit("OC_User", "post_addToGroup", array("uid" => $uid, "gid" => $gid));
  			return true;
  		} else {

  			return false;
  		}
  	}
  
  	/**

  	 * Removes a user from a group

  	 * @param string $uid Name of the user to remove from group
  	 * @param string $gid Name of the group from which remove the user
  	 * @return bool
  	 *
  	 * removes the user from a group.
  	 */

  	public static function removeFromGroup($uid, $gid) {
  		$group = self::getManager()->get($gid);
  		$user = self::$userManager->get($uid);
  		if ($group and $user) {
  			OC_Hook::emit("OC_Group", "pre_removeFromGroup", array("run" => true, "uid" => $uid, "gid" => $gid));
  			$group->removeUser($user);
  			OC_Hook::emit("OC_User", "post_removeFromGroup", array("uid" => $uid, "gid" => $gid));

  			return true;

  		} else {

  			return false;
  		}
  	}
  
  	/**

  	 * 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 static function getUserGroups($uid) {
  		$user = self::$userManager->get($uid);
  		if ($user) {

  			return self::getManager()->getUserGroupIds($user);

  		} else {
  			return array();

  		}

  	}
  
  	/**

  	 * get a list of all groups
  	 * @param string $search
  	 * @param int|null $limit
  	 * @param int|null $offset
  	 * @return array an array of group names

  	 *
  	 * Returns a list with all groups
  	 */

  	public static function getGroups($search = '', $limit = null, $offset = null) {
  		$groups = self::getManager()->search($search, $limit, $offset);
  		$groupIds = array();
  		foreach ($groups as $group) {
  			$groupIds[] = $group->getGID();

  		}

  		return $groupIds;

  	}
  
  	/**
  	 * check if a group exists

  	 *

  	 * @param string $gid
  	 * @return bool
  	 */
  	public static function groupExists($gid) {

  		return self::getManager()->groupExists($gid);

  	}
  
  	/**

  	 * 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 static function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {

  		$group = self::getManager()->get($gid);
  		if ($group) {
  			$users = $group->searchUsers($search, $limit, $offset);
  			$userIds = array();
  			foreach ($users as $user) {
  				$userIds[] = $user->getUID();
  			}
  			return $userIds;
  		} else {
  			return array();

  		}

  	}
  
  	/**

  	 * get a list of all users in several groups
  	 * @param string[] $gids

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

  	 * @return array an array of user ids

  	 */
  	public static function usersInGroups($gids, $search = '', $limit = -1, $offset = 0) {
  		$users = array();
  		foreach ($gids as $gid) {
  			// TODO Need to apply limits to groups as total
  			$users = array_merge(array_diff(self::usersInGroup($gid, $search, $limit, $offset), $users), $users);
  		}
  		return $users;
  	}
  
  	/**

  	 * get a list of all display names in a group
  	 * @param string $gid
  	 * @param string $search
  	 * @param int $limit
  	 * @param int $offset
  	 * @return array an array of display names (value) and user ids(key)

  	 */
  	public static function displayNamesInGroup($gid, $search = '', $limit = -1, $offset = 0) {

  		return self::getManager()->displayNamesInGroup($gid, $search, $limit, $offset);

  	}
  
  	/**

  	 * get a list of all display names in several groups

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

  	 * @return array an array of display names (Key) user ids (value)

  	 */
  	public static function displayNamesInGroups($gids, $search = '', $limit = -1, $offset = 0) {
  		$displayNames = array();
  		foreach ($gids as $gid) {
  			// TODO Need to apply limits to groups as total
  			$diff = array_diff(
  				self::displayNamesInGroup($gid, $search, $limit, $offset),
  				$displayNames
  			);
  			if ($diff) {
  				$displayNames = array_merge($diff, $displayNames);
  			}
  		}
  		return $displayNames;
  	}
  }