<?php
  
  /**
   * ownCloud – LDAP Helper
   *
   * @author Arthur 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\lib;
  
  class Helper {
  
  	/**
  	 * @brief returns prefixes for each saved LDAP/AD server configuration.
  	 * @param bool optional, whether only active configuration shall be
  	 * retrieved, defaults to false
  	 * @return array with a list of the available prefixes
  	 *
  	 * Configuration prefixes are used to set up configurations for n LDAP or
  	 * AD servers. Since configuration is stored in the database, table
  	 * appconfig under appid user_ldap, the common identifiers in column
  	 * 'configkey' have a prefix. The prefix for the very first server
  	 * configuration is empty.
  	 * Configkey Examples:
  	 * Server 1: ldap_login_filter
  	 * Server 2: s1_ldap_login_filter
  	 * Server 3: s2_ldap_login_filter
  	 *
  	 * The prefix needs to be passed to the constructor of Connection class,
  	 * except the default (first) server shall be connected to.
  	 *
  	 */
  	static public function getServerConfigurationPrefixes($activeConfigurations = false) {
  		$referenceConfigkey = 'ldap_configuration_active';
  
  		$query = '
  			SELECT DISTINCT `configkey`
  			FROM `*PREFIX*appconfig`
  			WHERE `appid` = \'user_ldap\'
  				AND `configkey` LIKE ?
  		';
  		if($activeConfigurations) {
  			if(\OC_Config::getValue( 'dbtype', 'sqlite' ) === 'oci') {
  				//FIXME oracle hack: need to explicitly cast CLOB to CHAR for comparison
  				$query .= ' AND to_char(`configvalue`) = \'1\'';
  			} else {
  				$query .= ' AND `configvalue` = \'1\'';
  			}
  		}
  		$query = \OCP\DB::prepare($query);
  
  		$serverConfigs = $query->execute(array('%'.$referenceConfigkey))->fetchAll();
  		$prefixes = array();
  
  		foreach($serverConfigs as $serverConfig) {
  			$len = strlen($serverConfig['configkey']) - strlen($referenceConfigkey);
  			$prefixes[] = substr($serverConfig['configkey'], 0, $len);
  		}
  
  		return $prefixes;
  	}
  
  	/**
  	 * @brief deletes a given saved LDAP/AD server configuration.
  	 * @param string the configuration prefix of the config to delete
  	 * @return bool true on success, false otherwise
  	 */
  	static public function deleteServerConfiguration($prefix) {
  		//just to be on the safe side
  		\OCP\User::checkAdminUser();
  
  		if(!in_array($prefix, self::getServerConfigurationPrefixes())) {
  			return false;
  		}
  
  		$query = \OCP\DB::prepare('
  			DELETE
  			FROM `*PREFIX*appconfig`
  			WHERE `configkey` LIKE ?
  				AND `appid` = \'user_ldap\'
  				AND `configkey` NOT IN (\'enabled\', \'installed_version\', \'types\', \'bgjUpdateGroupsLastRun\')
  		');
  		$delRows = $query->execute(array($prefix.'%'));
  
  		if(\OCP\DB::isError($delRows)) {
  			return false;
  		}
  
  		if($delRows == 0) {
  			return false;
  		}
  
  		return true;
  	}
  
  	/**
  	 * Truncate's the given mapping table
  	 *
  	 * @param string $mapping either 'user' or 'group'
  	 * @return boolean true on success, false otherwise
  	 */
  	static public function clearMapping($mapping) {
  		if($mapping === 'user') {
  			$table = '`*PREFIX*ldap_user_mapping`';
  		} else if ($mapping === 'group') {
  			$table = '`*PREFIX*ldap_group_mapping`';
  		} else {
  			return false;
  		}
  
  		$dbtype = \OCP\Config::getSystemValue('dbtype');
  		if(strpos($dbtype, 'sqlite') !== false
  			|| $dbtype === 'oci') {
  			$query = \OCP\DB::prepare('DELETE FROM '.$table);
  		} else {
  			$query = \OCP\DB::prepare('TRUNCATE '.$table);
  		}
  
  
  		$res = $query->execute();
  
  		if(\OCP\DB::isError($res)) {
  			return false;
  		}
  
  		return true;
  	}
  }