<?php
  
  /**
   * Copyright (c) 2013 Robin Appelman <icewind@owncloud.com>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC\Group;
  
  use OC\Hooks\PublicEmitter;
  
  /**
   * Class Manager
   *
   * Hooks available in scope \OC\Group:
   * - preAddUser(\OC\Group\Group $group, \OC\User\User $user)
   * - postAddUser(\OC\Group\Group $group, \OC\User\User $user)
   * - preRemoveUser(\OC\Group\Group $group, \OC\User\User $user)
   * - postRemoveUser(\OC\Group\Group $group, \OC\User\User $user)
   * - preDelete(\OC\Group\Group $group)
   * - postDelete(\OC\Group\Group $group)
   * - preCreate(string $groupId)
   * - postCreate(\OC\Group\Group $group)
   *
   * @package OC\Group
   */
  class Manager extends PublicEmitter {
  	/**
  	 * @var \OC_Group_Backend[] | \OC_Group_Database[] $backends
  	 */
  	private $backends = array();
  
  	/**
  	 * @var \OC\User\Manager $userManager
  	 */
  	private $userManager;
  
  	/**
  	 * @var \OC\Group\Group[]
  	 */
  	private $cachedGroups;
  
  	/**
  	 * @param \OC\User\Manager $userManager
  	 */
  	public function __construct($userManager) {
  		$this->userManager = $userManager;
  		$cache = & $this->cachedGroups;
  		$this->listen('\OC\Group', 'postDelete', function ($group) use (&$cache) {
  			/**
  			 * @var \OC\Group\Group $group
  			 */
  			unset($cache[$group->getGID()]);
  		});
  	}
  
  	/**
  	 * @param \OC_Group_Backend $backend
  	 */
  	public function addBackend($backend) {
  		$this->backends[] = $backend;
  	}
  
  	public function clearBackends() {
  		$this->backends = array();
  		$this->cachedGroups = array();
  	}
  
  	/**
  	 * @param string $gid
  	 * @return \OC\Group\Group
  	 */
  	public function get($gid) {
  		if (isset($this->cachedGroups[$gid])) {
  			return $this->cachedGroups[$gid];
  		}
  		foreach ($this->backends as $backend) {
  			if ($backend->groupExists($gid)) {
  				return $this->getGroupObject($gid);
  			}
  		}
  		return null;
  	}
  
  	protected function getGroupObject($gid) {
  		$backends = array();
  		foreach ($this->backends as $backend) {
  			if ($backend->groupExists($gid)) {
  				$backends[] = $backend;
  			}
  		}
  		$this->cachedGroups[$gid] = new Group($gid, $backends, $this->userManager, $this);
  		return $this->cachedGroups[$gid];
  	}
  
  	/**
  	 * @param string $gid
  	 * @return bool
  	 */
  	public function groupExists($gid) {
  		return !is_null($this->get($gid));
  	}
  
  	/**
  	 * @param string $gid
  	 * @return \OC\Group\Group
  	 */
  	public function createGroup($gid) {
  		if (!$gid) {
  			return false;
  		} else if ($this->groupExists($gid)) {
  			return $this->get($gid);
  		} else {
  			$this->emit('\OC\Group', 'preCreate', array($gid));
  			foreach ($this->backends as $backend) {
  				if ($backend->implementsActions(OC_GROUP_BACKEND_CREATE_GROUP)) {
  					$backend->createGroup($gid);
  					$group = $this->getGroupObject($gid);
  					$this->emit('\OC\Group', 'postCreate', array($group));
  					return $group;
  				}
  			}
  			return null;
  		}
  	}
  
  	/**
  	 * @param string $search
  	 * @param int $limit
  	 * @param int $offset
  	 * @return \OC\Group\Group[]
  	 */
  	public function search($search, $limit = null, $offset = null) {
  		$groups = array();
  		foreach ($this->backends as $backend) {
  			$groupIds = $backend->getGroups($search, $limit, $offset);

  			foreach ($groupIds as $groupId) {
  				$groups[$groupId] = $this->getGroupObject($groupId);
  			}
  			if (!is_null($limit) and $limit <= 0) {
  				return array_values($groups);
  			}
  		}
  		return array_values($groups);
  	}
  
  	/**
  	 * @param \OC\User\User $user
  	 * @return \OC\Group\Group[]
  	 */
  	public function getUserGroups($user) {
  		$groups = array();
  		foreach ($this->backends as $backend) {
  			$groupIds = $backend->getUserGroups($user->getUID());
  			foreach ($groupIds as $groupId) {
  				$groups[$groupId] = $this->getGroupObject($groupId);
  			}
  		}
  		return array_values($groups);
  	}

  
  	/**
  	 * @brief get a list of all display names in a group
  	 * @param string $gid
  	 * @param string $search
  	 * @param int $limit
  	 * @param int $offset
  	 * @return array with display names (value) and user ids (key)
  	 */
  	public function displayNamesInGroup($gid, $search = '', $limit = -1, $offset = 0) {
  		$group = $this->get($gid);
  		if(is_null($group)) {
  			return array();
  		}
  		// only user backends have the capability to do a complex search for users
  		$groupUsers  = $group->searchUsers('', $limit, $offset);
  		$search = trim($search);
  		if(!empty($search)) {
  			//TODO: for OC 7 earliest: user backend should get a method to check selected users against a pattern
  			$filteredUsers = $this->userManager->search($search);
  			$testUsers = true;
  		} else {
  			$filteredUsers = array();
  			$testUsers = false;
  		}
  
  		$matchingUsers = array();
  		foreach($groupUsers as $user) {
  			if(!$testUsers || isset($filteredUsers[$user->getUID()])) {
  				$matchingUsers[$user->getUID()] = $user->getDisplayName();
  			}
  		}
  		return $matchingUsers;
  	}

  }