<?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/>.
   *
   */
  /*
   *
   * The following SQL statement is just a help for developers and will not be
   * executed!
   *
   * CREATE TABLE `users` (
   *   `uid` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
   *   `password` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
   *   PRIMARY KEY (`uid`)
   * ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
   *
   */
  
  require_once 'phpass/PasswordHash.php';
  
  /**
   * Class for user management in a SQL Database (e.g. MySQL, SQLite)
   */
  class OC_User_Database extends OC_User_Backend {
  	/**
  	 * @var PasswordHash
  	 */
  	static private $hasher=null;
  
  	private function getHasher() {
  		if(!self::$hasher) {
  			//we don't want to use DES based crypt(), since it doesn't return a has with a recognisable prefix
  			$forcePortable=(CRYPT_BLOWFISH!=1);
  			self::$hasher=new PasswordHash(8, $forcePortable);
  		}
  		return self::$hasher;
  
  	}
  
  	/**
  	 * @brief Create a new user
  	 * @param $uid The username of the user to create
  	 * @param $password The password of the new user
  	 * @returns true/false
  	 *
  	 * Creates a new user. Basic checking of username is done in OC_User
  	 * itself, not in its subclasses.
  	 */
  	public function createUser( $uid, $password ) {
  		if( $this->userExists($uid) ) {
  			return false;
  		}else{
  			$hasher=$this->getHasher();
  			$hash = $hasher->HashPassword($password.OC_Config::getValue('passwordsalt', ''));
  			$query = OC_DB::prepare( 'INSERT INTO `*PREFIX*users` ( `uid`, `password` ) VALUES( ?, ? )' );
  			$result = $query->execute( array( $uid, $hash));
  
  			return $result ? true : false;
  		}
  	}
  
  	/**
  	 * @brief delete a user
  	 * @param $uid The username of the user to delete
  	 * @returns true/false
  	 *
  	 * Deletes a user
  	 */
  	public function deleteUser( $uid ) {
  		// Delete user-group-relation
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*users` WHERE `uid` = ?' );
  		$query->execute( array( $uid ));
  		return true;
  	}
  
  	/**
  	 * @brief Set password
  	 * @param $uid The username
  	 * @param $password The new password
  	 * @returns true/false
  	 *
  	 * Change the password of a user
  	 */
  	public function setPassword( $uid, $password ) {
  		if( $this->userExists($uid) ) {
  			$hasher=$this->getHasher();
  			$hash = $hasher->HashPassword($password.OC_Config::getValue('passwordsalt', ''));
  			$query = OC_DB::prepare( 'UPDATE `*PREFIX*users` SET `password` = ? WHERE `uid` = ?' );
  			$query->execute( array( $hash, $uid ));
  
  			return true;
  		}else{
  			return false;
  		}
  	}
  
  	/**
  	 * @brief Set display name
  	 * @param $uid The username
  	 * @param $displayName The new display name
  	 * @returns true/false
  	 *
  	 * Change the display name of a user
  	 */
  	public function setDisplayName( $uid, $displayName ) {
  		if( $this->userExists($uid) ) {
  			$query = OC_DB::prepare( 'UPDATE `*PREFIX*users` SET `displayname` = ? WHERE `uid` = ?' );
  			$query->execute( array( $displayName, $uid ));
  			return true;
  		}else{
  			return false;
  		}
  	}
  
  	/**
  	 * @brief get display name of the user
  	 * @param $uid user ID of the user
  	 * @return display name
  	 */
  	public function getDisplayName($uid) {
  		if( $this->userExists($uid) ) {
  			$query = OC_DB::prepare( 'SELECT `displayname` FROM `*PREFIX*users` WHERE `uid` = ?' );
  			$result = $query->execute( array( $uid ))->fetchAll();
  			$displayName = trim($result[0]['displayname'], ' ');
  			if ( !empty($displayName) ) {
  				return $displayName;
  			} else {
  				return $uid;
  			}
  		}
  	}
  
  	/**
  	 * @brief Get a list of all display names
  	 * @returns array with  all displayNames (value) and the correspondig uids (key)
  	 *
  	 * Get a list of all display names and user ids.
  	 */
  	public function getDisplayNames($search = '', $limit = null, $offset = null) {
  		$displayNames = array();
  		$query = OC_DB::prepare('SELECT `uid`, `displayname` FROM `*PREFIX*users`'
  			.' WHERE LOWER(`displayname`) LIKE LOWER(?)', $limit, $offset);
  		$result = $query->execute(array($search.'%'));
  		$users = array();
  		while ($row = $result->fetchRow()) {
  			$displayNames[$row['uid']] = $row['displayname'];
  		}
  
  		// let's see if we can also find some users who don't have a display name yet
  		$query = OC_DB::prepare('SELECT `uid`, `displayname` FROM `*PREFIX*users`'
  			.' WHERE LOWER(`uid`) LIKE LOWER(?)', $limit, $offset);
  		$result = $query->execute(array($search.'%'));
  		while ($row = $result->fetchRow()) {
  			$displayName =  trim($row['displayname'], ' ');
  			if ( empty($displayName) ) {
  				$displayNames[$row['uid']] = $row['uid'];
  			}
  		}
  
  
  		return $displayNames;
  	}
  
  	/**
  	 * @brief Check if the password is correct
  	 * @param $uid The username
  	 * @param $password The password
  	 * @returns string
  	 *
  	 * Check if the password is correct without logging in the user
  	 * returns the user id or false
  	 */
  	public function checkPassword( $uid, $password ) {
  		$query = OC_DB::prepare( 'SELECT `uid`, `password` FROM `*PREFIX*users` WHERE LOWER(`uid`) = LOWER(?)' );
  		$result = $query->execute( array( $uid));
  
  		$row=$result->fetchRow();
  		if($row) {
  			$storedHash=$row['password'];
  			if ($storedHash[0]=='$') {//the new phpass based hashing
  				$hasher=$this->getHasher();
  				if($hasher->CheckPassword($password.OC_Config::getValue('passwordsalt', ''), $storedHash)) {
  					return $row['uid'];
  				}else{
  					return false;
  				}
  			}else{//old sha1 based hashing
  				if(sha1($password)==$storedHash) {
  					//upgrade to new hashing
  					$this->setPassword($row['uid'], $password);
  					return $row['uid'];
  				}else{
  					return false;
  				}
  			}
  		}else{
  			return false;
  		}
  	}
  
  	/**
  	 * @brief Get a list of all users
  	 * @returns array with all uids
  	 *
  	 * Get a list of all users.
  	 */
  	public function getUsers($search = '', $limit = null, $offset = null) {
  		$query = OC_DB::prepare('SELECT `uid` FROM `*PREFIX*users` WHERE LOWER(`uid`) LIKE LOWER(?)', $limit, $offset);
  		$result = $query->execute(array($search.'%'));
  		$users = array();
  		while ($row = $result->fetchRow()) {
  			$users[] = $row['uid'];
  		}
  		return $users;
  	}
  
  	/**
  	 * @brief check if a user exists
  	 * @param string $uid the username
  	 * @return boolean
  	 */
  	public function userExists($uid) {
  		$query = OC_DB::prepare( 'SELECT * FROM `*PREFIX*users` WHERE LOWER(`uid`) = LOWER(?)' );
  		$result = $query->execute( array( $uid ));
  		if (OC_DB::isError($result)) {
  			OC_Log::write('core', OC_DB::getErrorMessage($result), OC_Log::ERROR);
  			return false;
  		}
  		return $result->numRows() > 0;
  	}
  
  	/**
  	* @brief get the user's home directory
  	* @param string $uid the username
  	* @return boolean
  	*/
  	public function getHome($uid) {
  		if($this->userExists($uid)) {
  			return OC_Config::getValue( "datadirectory", OC::$SERVERROOT."/data" ) . '/' . $uid;
  		}else{
  			return false;
  		}
  	}
  
  	/**
  	 * @return bool
  	 */
  	public function hasUserListings() {
  		return true;
  	}
  
  }