<?php
  
  /**
   * ownCloud – LDAP group backend
   *
   * @author Arthur Schiwon
   * @copyright 2012 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\Access;
  use OCA\user_ldap\lib\BackendUtility;
  
  class GROUP_LDAP extends BackendUtility implements \OCP\GroupInterface {

  	protected $enabled = false;

  	public function __construct(Access $access) {
  		parent::__construct($access);
  		$filter = $this->access->connection->ldapGroupFilter;
  		$gassoc = $this->access->connection->ldapGroupMemberAssocAttr;

  		if(!empty($filter) && !empty($gassoc)) {
  			$this->enabled = true;
  		}
  	}
  
  	/**
  	 * @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, $gid) {
  		if(!$this->enabled) {
  			return false;
  		}

  		if($this->access->connection->isCached('inGroup'.$uid.':'.$gid)) {
  			return $this->access->connection->getFromCache('inGroup'.$uid.':'.$gid);

  		}

  		$dn_user = $this->access->username2dn($uid);
  		$dn_group = $this->access->groupname2dn($gid);

  		// just in case
  		if(!$dn_group || !$dn_user) {

  			$this->access->connection->writeToCache('inGroup'.$uid.':'.$gid, false);

  			return false;
  		}
  		//usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.

  		$members = $this->access->readAttribute($dn_group,
  						$this->access->connection->ldapGroupMemberAssocAttr);

  		if(!$members) {

  			$this->access->connection->writeToCache('inGroup'.$uid.':'.$gid, false);

  			return false;
  		}
  
  		//extra work if we don't get back user DNs
  		//TODO: this can be done with one LDAP query

  		if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {

  			$dns = array();
  			foreach($members as $mid) {

  				$filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
  				$ldap_users = $this->access->fetchListOfUsers($filter, 'dn');

  				if(count($ldap_users) < 1) {
  					continue;
  				}
  				$dns[] = $ldap_users[0];
  			}
  			$members = $dns;
  		}
  
  		$isInGroup = in_array($dn_user, $members);

  		$this->access->connection->writeToCache('inGroup'.$uid.':'.$gid, $isInGroup);

  
  		return $isInGroup;
  	}
  
  	/**
  	 * @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) {
  		if(!$this->enabled) {
  			return array();
  		}
  		$cacheKey = 'getUserGroups'.$uid;

  		if($this->access->connection->isCached($cacheKey)) {
  			return $this->access->connection->getFromCache($cacheKey);

  		}

  		$userDN = $this->access->username2dn($uid);

  		if(!$userDN) {

  			$this->access->connection->writeToCache($cacheKey, array());

  			return array();
  		}
  
  		//uniqueMember takes DN, memberuid the uid, so we need to distinguish

  		if((strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'uniquemember')
  			|| (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'member')

  		) {
  			$uid = $userDN;

  		} else if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
  			$result = $this->access->readAttribute($userDN, 'uid');

  			$uid = $result[0];
  		} else {
  			// just in case
  			$uid = $userDN;
  		}

  		$filter = $this->access->combineFilterWithAnd(array(
  			$this->access->connection->ldapGroupFilter,
  			$this->access->connection->ldapGroupMemberAssocAttr.'='.$uid

  		));

  		$groups = $this->access->fetchListOfGroups($filter,
  				array($this->access->connection->ldapGroupDisplayName, 'dn'));
  		$groups = array_unique($this->access->ownCloudGroupNames($groups), SORT_LOCALE_STRING);
  		$this->access->connection->writeToCache($cacheKey, $groups);

  
  		return $groups;
  	}
  
  	/**
  	 * @brief get a list of all users in a group
  	 * @returns array with user ids
  	 */
  	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
  		if(!$this->enabled) {
  			return array();
  		}
  		if(!$this->groupExists($gid)) {
  			return array();
  		}
  		$cachekey = 'usersInGroup-'.$gid.'-'.$search.'-'.$limit.'-'.$offset;
  		// check for cache of the exact query

  		$groupUsers = $this->access->connection->getFromCache($cachekey);

  		if(!is_null($groupUsers)) {
  			return $groupUsers;
  		}
  
  		// check for cache of the query without limit and offset

  		$groupUsers = $this->access->connection->getFromCache('usersInGroup-'.$gid.'-'.$search);

  		if(!is_null($groupUsers)) {
  			$groupUsers = array_slice($groupUsers, $offset, $limit);

  			$this->access->connection->writeToCache($cachekey, $groupUsers);

  			return $groupUsers;
  		}

  		if($limit === -1) {

  			$limit = null;
  		}

  		$groupDN = $this->access->groupname2dn($gid);

  		if(!$groupDN) {
  			// group couldn't be found, return empty resultset

  			$this->access->connection->writeToCache($cachekey, array());

  			return array();
  		}

  		$members = $this->access->readAttribute($groupDN,
  						$this->access->connection->ldapGroupMemberAssocAttr);

  		if(!$members) {
  			//in case users could not be retrieved, return empty resultset

  			$this->access->connection->writeToCache($cachekey, array());

  			return array();
  		}
  
  		$groupUsers = array();

  		$isMemberUid = (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid');

  		foreach($members as $member) {
  			if($isMemberUid) {
  				//we got uids, need to get their DNs to 'tranlsate' them to usernames

  				$filter = $this->access->combineFilterWithAnd(array(

  					\OCP\Util::mb_str_replace('%uid', $member,

  						$this->access->connection->ldapLoginFilter, 'UTF-8'),
  					$this->access->getFilterPartForUserSearch($search)

  				));

  				$ldap_users = $this->access->fetchListOfUsers($filter, 'dn');

  				if(count($ldap_users) < 1) {
  					continue;
  				}

  				$groupUsers[] = $this->access->dn2username($ldap_users[0]);

  			} else {
  				//we got DNs, check if we need to filter by search or we can give back all of them
  				if(!empty($search)) {

  					if(!$this->access->readAttribute($member,
  						$this->access->connection->ldapUserDisplayName,
  						$this->access->getFilterPartForUserSearch($search))) {

  						continue;
  					}
  				}
  				// dn2username will also check if the users belong to the allowed base

  				if($ocname = $this->access->dn2username($member)) {

  					$groupUsers[] = $ocname;
  				}
  			}
  		}
  		natsort($groupUsers);

  		$this->access->connection->writeToCache('usersInGroup-'.$gid.'-'.$search, $groupUsers);

  		$groupUsers = array_slice($groupUsers, $offset, $limit);

  		$this->access->connection->writeToCache($cachekey, $groupUsers);

  
  		return $groupUsers;
  	}
  
  	/**

  	 * @brief get a list of all groups
  	 * @returns array with group names
  	 *
  	 * Returns a list with all groups
  	 */
  	public function getGroups($search = '', $limit = -1, $offset = 0) {
  		if(!$this->enabled) {
  			return array();
  		}
  		$cachekey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
  
  		//Check cache before driving unnecessary searches
  		\OCP\Util::writeLog('user_ldap', 'getGroups '.$cachekey, \OCP\Util::DEBUG);

  		$ldap_groups = $this->access->connection->getFromCache($cachekey);

  		if(!is_null($ldap_groups)) {
  			return $ldap_groups;
  		}
  
  		// if we'd pass -1 to LDAP search, we'd end up in a Protocol
  		// error. With a limit of 0, we get 0 results. So we pass null.
  		if($limit <= 0) {
  			$limit = null;
  		}

  		$filter = $this->access->combineFilterWithAnd(array(
  			$this->access->connection->ldapGroupFilter,
  			$this->access->getFilterPartForGroupSearch($search)

  		));
  		\OCP\Util::writeLog('user_ldap', 'getGroups Filter '.$filter, \OCP\Util::DEBUG);

  		$ldap_groups = $this->access->fetchListOfGroups($filter,
  				array($this->access->connection->ldapGroupDisplayName, 'dn'),
  				$limit,
  				$offset);
  		$ldap_groups = $this->access->ownCloudGroupNames($ldap_groups);

  		$this->access->connection->writeToCache($cachekey, $ldap_groups);

  		return $ldap_groups;
  	}
  
  	public function groupMatchesFilter($group) {
  		return (strripos($group, $this->groupSearch) !== false);
  	}
  
  	/**
  	 * check if a group exists
  	 * @param string $gid
  	 * @return bool
  	 */
  	public function groupExists($gid) {

  		if($this->access->connection->isCached('groupExists'.$gid)) {
  			return $this->access->connection->getFromCache('groupExists'.$gid);

  		}

  		//getting dn, if false the group does not exist. If dn, it may be mapped
  		//only, requires more checking.
  		$dn = $this->access->groupname2dn($gid);

  		if(!$dn) {

  			$this->access->connection->writeToCache('groupExists'.$gid, false);

  			return false;
  		}
  
  		//if group really still exists, we will be able to read its objectclass

  		$objcs = $this->access->readAttribute($dn, 'objectclass');

  		if(!$objcs || empty($objcs)) {

  			$this->access->connection->writeToCache('groupExists'.$gid, false);

  			return false;
  		}

  		$this->access->connection->writeToCache('groupExists'.$gid, true);

  		return true;
  	}
  
  	/**
  	* @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) {

  		return false;

  	}
  }