<?php
  /**
   * ownCloud
   *
   * @author Frank Karlitschek
   * @author Jakob Sack
   * @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  `preferences` (
   * `userid` VARCHAR( 255 ) NOT NULL ,
   * `appid` VARCHAR( 255 ) NOT NULL ,
   * `configkey` VARCHAR( 255 ) NOT NULL ,
   * `configvalue` VARCHAR( 255 ) NOT NULL
   * )
   *
   */
  
  /**
   * This class provides an easy way for storing user preferences.
   */
  class OC_Preferences{
  	/**
  	 * @brief Get all users using the preferences
  	 * @return array with user ids
  	 *
  	 * This function returns a list of all users that have at least one entry
  	 * in the preferences table.
  	 */
  	public static function getUsers() {
  		// No need for more comments
  		$query = OC_DB::prepare( 'SELECT DISTINCT( `userid` ) FROM `*PREFIX*preferences`' );
  		$result = $query->execute();
  
  		$users = array();
  		while( $row = $result->fetchRow()) {
  			$users[] = $row["userid"];
  		}
  
  		return $users;
  	}
  
  	/**
  	 * @brief Get all apps of a user
  	 * @param string $user user
  	 * @return array with app ids
  	 *
  	 * This function returns a list of all apps of the user that have at least
  	 * one entry in the preferences table.
  	 */
  	public static function getApps( $user ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'SELECT DISTINCT( `appid` ) FROM `*PREFIX*preferences` WHERE `userid` = ?' );
  		$result = $query->execute( array( $user ));
  
  		$apps = array();
  		while( $row = $result->fetchRow()) {
  			$apps[] = $row["appid"];
  		}
  
  		return $apps;
  	}
  
  	/**
  	 * @brief Get the available keys for an app
  	 * @param string $user user
  	 * @param string $app the app we are looking for
  	 * @return array with key names
  	 *
  	 * This function gets all keys of an app of an user. Please note that the
  	 * values are not returned.
  	 */
  	public static function getKeys( $user, $app ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'SELECT `configkey` FROM `*PREFIX*preferences` WHERE `userid` = ? AND `appid` = ?' );
  		$result = $query->execute( array( $user, $app ));
  
  		$keys = array();
  		while( $row = $result->fetchRow()) {
  			$keys[] = $row["configkey"];
  		}
  
  		return $keys;
  	}
  
  	/**
  	 * @brief Gets the preference
  	 * @param string $user user
  	 * @param string $app app
  	 * @param string $key key
  	 * @param string $default = null, default value if the key does not exist
  	 * @return string the value or $default
  	 *
  	 * This function gets a value from the preferences table. If the key does
  	 * not exist the default value will be returned
  	 */
  	public static function getValue( $user, $app, $key, $default = null ) {
  		// Try to fetch the value, return default if not exists.
  		$query = OC_DB::prepare( 'SELECT `configvalue` FROM `*PREFIX*preferences`'
  			.' WHERE `userid` = ? AND `appid` = ? AND `configkey` = ?' );
  		$result = $query->execute( array( $user, $app, $key ));
  
  		$row = $result->fetchRow();
  		if($row) {
  			return $row["configvalue"];
  		}else{
  			return $default;
  		}
  	}
  
  	/**
  	 * @brief sets a value in the preferences
  	 * @param string $user user
  	 * @param string $app app
  	 * @param string $key key
  	 * @param string $value value
  	 * @return bool
  	 *
  	 * Adds a value to the preferences. If the key did not exist before, it
  	 * will be added automagically.
  	 */
  	public static function setValue( $user, $app, $key, $value ) {
  		// Check if the key does exist
  		$query = OC_DB::prepare( 'SELECT `configvalue` FROM `*PREFIX*preferences`'
  			.' WHERE `userid` = ? AND `appid` = ? AND `configkey` = ?' );
  		$values=$query->execute(array($user, $app, $key))->fetchAll();
  		$exists=(count($values)>0);
  
  		if( !$exists ) {
  			$query = OC_DB::prepare( 'INSERT INTO `*PREFIX*preferences`'
  				.' ( `userid`, `appid`, `configkey`, `configvalue` ) VALUES( ?, ?, ?, ? )' );
  			$query->execute( array( $user, $app, $key, $value ));
  		}
  		else{
  			$query = OC_DB::prepare( 'UPDATE `*PREFIX*preferences` SET `configvalue` = ?'
  				.' WHERE `userid` = ? AND `appid` = ? AND `configkey` = ?' );
  			$query->execute( array( $value, $user, $app, $key ));
  		}
  		return true;
  	}
  
  	/**
  	 * @brief Deletes a key
  	 * @param string $user user
  	 * @param string $app app
  	 * @param string $key key
  	 * @return bool
  	 *
  	 * Deletes a key.
  	 */
  	public static function deleteKey( $user, $app, $key ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*preferences`'
  			.' WHERE `userid` = ? AND `appid` = ? AND `configkey` = ?' );
  		$query->execute( array( $user, $app, $key ));
  
  		return true;
  	}
  
  	/**
  	 * @brief Remove app of user from preferences
  	 * @param string $user user
  	 * @param string $app app
  	 * @return bool
  	 *
  	 * Removes all keys in appconfig belonging to the app and the user.
  	 */
  	public static function deleteApp( $user, $app ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*preferences` WHERE `userid` = ? AND `appid` = ?' );
  		$query->execute( array( $user, $app ));
  
  		return true;
  	}
  
  	/**
  	 * @brief Remove user from preferences
  	 * @param string $user user
  	 * @return bool
  	 *
  	 * Removes all keys in appconfig belonging to the user.
  	 */
  	public static function deleteUser( $user ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*preferences` WHERE `userid` = ?' );
  		$query->execute( array( $user ));
  
  		return true;
  	}
  
  	/**
  	 * @brief Remove app from all users
  	 * @param string $app app
  	 * @return bool
  	 *
  	 * Removes all keys in preferences belonging to the app.
  	 */
  	public static function deleteAppFromAllUsers( $app ) {
  		// No need for more comments
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*preferences` WHERE `appid` = ?' );
  		$query->execute( array( $app ));
  
  		return true;
  	}
  }