<?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 hash 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 LOWER(`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 string display name

  	 */
  	public function getDisplayName($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(?) OR '
  			. 'LOWER(`uid`) LIKE LOWER(?)', $limit, $offset);
  		$result = $query->execute(array($search . '%', $search . '%'));

  		$users = array();
  		while ($row = $result->fetchRow()) {
  			$displayNames[$row['uid']] = $row['displayname'];
  		}

  		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 COUNT(*) 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->fetchOne() > 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;
  	}

  	/**
  	 * counts the users in the database
  	 *
  	 * @return int | bool
  	 */
  	public function countUsers() {
  		$query = OC_DB::prepare('SELECT COUNT(*) FROM `*PREFIX*users`');
  		$result = $query->execute();
  		if (OC_DB::isError($result)) {
  			OC_Log::write('core', OC_DB::getErrorMessage($result), OC_Log::ERROR);
  			return false;
  		}
  		return $result->fetchOne();
  	}

  }