<?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  `appconfig` (
   * `appid` VARCHAR( 255 ) NOT NULL ,
   * `configkey` VARCHAR( 255 ) NOT NULL ,
   * `configvalue` VARCHAR( 255 ) NOT NULL
   * )
   *
   */
  
  /**
   * This class provides an easy way for apps to store config values in the
   * database.
   */
  class OC_Appconfig{
  	/**
  	 * @brief Get all apps using the config
  	 * @return array with app ids
  	 *
  	 * This function returns a list of all apps that have at least one
  	 * entry in the appconfig table.
  	 */
  	public static function getApps() {
  		// No magic in here!
  		$query = OC_DB::prepare( 'SELECT DISTINCT `appid` FROM `*PREFIX*appconfig`' );
  		$result = $query->execute();
  
  		$apps = array();
  		while( $row = $result->fetchRow()) {
  			$apps[] = $row["appid"];
  		}
  
  		return $apps;
  	}
  
  	/**
  	 * @brief Get the available keys for an app
  	 * @param string $app the app we are looking for
  	 * @return array with key names
  	 *
  	 * This function gets all keys of an app. Please note that the values are
  	 * not returned.
  	 */
  	public static function getKeys( $app ) {
  		// No magic in here as well
  		$query = OC_DB::prepare( 'SELECT `configkey` FROM `*PREFIX*appconfig` WHERE `appid` = ?' );
  		$result = $query->execute( array( $app ));
  
  		$keys = array();
  		while( $row = $result->fetchRow()) {
  			$keys[] = $row["configkey"];
  		}
  
  		return $keys;
  	}
  
  	/**
  	 * @brief Gets the config value
  	 * @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 appconfig table. If the key does
  	 * not exist the default value will be returned
  	 */
  	public static function getValue( $app, $key, $default = null ) {
  		// At least some magic in here :-)
  		$query = OC_DB::prepare( 'SELECT `configvalue` FROM `*PREFIX*appconfig`'
  			.' WHERE `appid` = ? AND `configkey` = ?' );
  		$result = $query->execute( array( $app, $key ));
  		$row = $result->fetchRow();
  		if($row) {
  			return $row["configvalue"];
  		}else{
  			return $default;
  		}
  	}
  
  	/**
  	 * @brief check if a key is set in the appconfig
  	 * @param string $app
  	 * @param string $key
  	 * @return bool
  	 */
  	public static function hasKey($app, $key) {
  		$exists = self::getKeys( $app );
  		return in_array( $key, $exists );
  	}
  
  	/**
  	 * @brief sets a value in the appconfig
  	 * @param string $app app
  	 * @param string $key key
  	 * @param string $value value
  	 * @return bool
  	 *
  	 * Sets a value. If the key did not exist before it will be created.
  	 */
  	public static function setValue( $app, $key, $value ) {
  		// Does the key exist? yes: update. No: insert
  		if(! self::hasKey($app, $key)) {

  			$query = OC_DB::prepare( 'INSERT INTO `*PREFIX*appconfig` ( `appid`, `configkey`, `configvalue` )'
  				.' VALUES( ?, ?, ? )' );
  			$query->execute( array( $app, $key, $value ));

  		}
  		else{

  			$query = OC_DB::prepare( 'UPDATE `*PREFIX*appconfig` SET `configvalue` = ?'
  				.' WHERE `appid` = ? AND `configkey` = ?' );
  			$query->execute( array( $value, $app, $key ));

  		}

  		// TODO where should this be documented?
  		\OC_Hook::emit('OC_Appconfig', 'post_set_value', array(
  			'app' => $app,
  			'key' => $key,
  			'value' => $value
  		));

  	}
  
  	/**
  	 * @brief Deletes a key
  	 * @param string $app app
  	 * @param string $key key
  	 * @return bool
  	 *
  	 * Deletes a key.
  	 */
  	public static function deleteKey( $app, $key ) {
  		// Boring!
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*appconfig` WHERE `appid` = ? AND `configkey` = ?' );
  		$query->execute( array( $app, $key ));
  
  		return true;
  	}
  
  	/**
  	 * @brief Remove app from appconfig
  	 * @param string $app app
  	 * @return bool
  	 *
  	 * Removes all keys in appconfig belonging to the app.
  	 */
  	public static function deleteApp( $app ) {
  		// Nothing special
  		$query = OC_DB::prepare( 'DELETE FROM `*PREFIX*appconfig` WHERE `appid` = ?' );
  		$query->execute( array( $app ));
  
  		return true;
  	}
  
  	/**
  	 * get multiply values, either the app or key can be used as wildcard by setting it to false
  	 * @param app
  	 * @param key
  	 * @return array
  	 */
  	public static function getValues($app, $key) {
  		if($app!==false and $key!==false) {
  			return false;
  		}
  		$fields='`configvalue`';
  		$where='WHERE';
  		$params=array();
  		if($app!==false) {
  			$fields.=', `configkey`';
  			$where.=' `appid` = ?';
  			$params[]=$app;
  			$key='configkey';
  		}else{
  			$fields.=', `appid`';
  			$where.=' `configkey` = ?';
  			$params[]=$key;
  			$key='appid';
  		}
  		$queryString='SELECT '.$fields.' FROM `*PREFIX*appconfig` '.$where;
  		$query=OC_DB::prepare($queryString);
  		$result=$query->execute($params);
  		$values=array();
  		while($row=$result->fetchRow()) {
  			$values[$row[$key]]=$row['configvalue'];
  		}
  		return $values;
  	}
  }