<?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
   * )
   *
   */

  namespace OC;
  
  use \OC\DB\Connection;

  /**
   * This class provides an easy way for apps to store config values in the
   * database.
   */

  class AppConfig implements \OCP\IAppConfig {
  	/**
  	 * @var \OC\DB\Connection $conn
  	 */
  	protected $conn;
  
  	private $cache = array();
  
  	private $appsLoaded = array();
  
  	/**
  	 * @var string[]
  	 */
  	private $apps = null;
  
  	/**
  	 * @param \OC\DB\Connection $conn
  	 */
  	public function __construct(Connection $conn) {
  		$this->conn = $conn;
  	}
  
  	/**
  	 * @param string $app
  	 * @return string[]
  	 */
  	private function getAppCache($app) {
  		if (!isset($this->cache[$app])) {
  			$this->cache[$app] = array();
  		}
  		return $this->cache[$app];
  	}
  
  	/**
  	 * @param string $app
  	 * @return \string[]
  	 */
  	private function getAppValues($app) {
  		$appCache = $this->getAppCache($app);
  		if (array_search($app, $this->appsLoaded) === false) {
  			$query = 'SELECT `configvalue`, `configkey` FROM `*PREFIX*appconfig`'
  				. ' WHERE `appid` = ?';
  			$result = $this->conn->executeQuery($query, array($app));
  			while ($row = $result->fetch()) {
  				$appCache[$row['configkey']] = $row['configvalue'];
  			}
  			$this->appsLoaded[] = $app;
  		}
  		$this->cache[$app] = $appCache;
  		return $appCache;
  	}

  	/**

  	 * Get all apps using the config
  	 *
  	 * @return array an array of app ids

  	 *
  	 * This function returns a list of all apps that have at least one
  	 * entry in the appconfig table.
  	 */

  	public function getApps() {
  		if (is_array($this->apps)) {
  			return $this->apps;
  		}
  		$query = 'SELECT DISTINCT `appid` FROM `*PREFIX*appconfig` ORDER BY `appid`';
  		$result = $this->conn->executeQuery($query);

  
  		$apps = array();

  		while ($appid = $result->fetchColumn()) {
  			$apps[] = $appid;

  		}

  		$this->apps = $apps;

  		return $apps;
  	}
  
  	/**

  	 * Get the available keys for an app
  	 *

  	 * @param string $app the app we are looking for

  	 * @return array an array of key names

  	 *
  	 * This function gets all keys of an app. Please note that the values are
  	 * not returned.
  	 */

  	public function getKeys($app) {
  		$values = $this->getAppValues($app);
  		$keys = array_keys($values);
  		sort($keys);

  		return $keys;
  	}
  
  	/**

  	 * 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 function getValue($app, $key, $default = null) {
  		$values = $this->getAppValues($app);
  		if (isset($values[$key])) {
  			return $values[$key];
  		} else {

  			return $default;
  		}
  	}
  
  	/**

  	 * check if a key is set in the appconfig
  	 *

  	 * @param string $app
  	 * @param string $key
  	 * @return bool
  	 */

  	public function hasKey($app, $key) {
  		$values = $this->getAppValues($app);
  		return array_key_exists($key, $values);

  	}
  
  	/**

  	 * sets a value in the appconfig
  	 *

  	 * @param string $app app
  	 * @param string $key key
  	 * @param string $value value

  	 *
  	 * Sets a value. If the key did not exist before it will be created.
  	 */

  	public function setValue($app, $key, $value) {
  		// Does the key exist? no: insert, yes: update.
  		if (!$this->hasKey($app, $key)) {
  			$data = array(
  				'appid' => $app,
  				'configkey' => $key,
  				'configvalue' => $value,
  			);
  			$this->conn->insert('*PREFIX*appconfig', $data);
  		} else {
  			$oldValue = $this->getValue($app, $key);
  			if($oldValue === strval($value)) {
  				return true;
  			}
  			$data = array(
  				'configvalue' => $value,
  			);
  			$where = array(
  				'appid' => $app,
  				'configkey' => $key,
  			);
  			$this->conn->update('*PREFIX*appconfig', $data, $where);
  		}
  		if (!isset($this->cache[$app])) {
  			$this->cache[$app] = array();

  		}

  		if (is_array($this->apps) and array_search($app, $this->apps) === false) {
  			$this->apps[$app] = $app;

  		}

  		$this->cache[$app][$key] = $value;

  	}
  
  	/**

  	 * Deletes a key
  	 *

  	 * @param string $app app
  	 * @param string $key key

  	 * @return boolean|null

  	 */

  	public function deleteKey($app, $key) {
  		$where = array(
  			'appid' => $app,
  			'configkey' => $key,
  		);
  		$this->conn->delete('*PREFIX*appconfig', $where);
  		if (isset($this->cache[$app]) and isset($this->cache[$app][$key])) {
  			unset($this->cache[$app][$key]);
  		}

  	}
  
  	/**

  	 * Remove app from appconfig
  	 *

  	 * @param string $app app

  	 * @return boolean|null

  	 *
  	 * Removes all keys in appconfig belonging to the app.
  	 */

  	public function deleteApp($app) {
  		$where = array(
  			'appid' => $app,
  		);
  		$this->conn->delete('*PREFIX*appconfig', $where);
  		unset($this->cache[$app]);
  		unset($this->apps[$app]);

  	}
  
  	/**
  	 * get multiply values, either the app or key can be used as wildcard by setting it to false

  	 *
  	 * @param string|false $app
  	 * @param string|false $key

  	 * @return array
  	 */

  	public function getValues($app, $key) {
  		if (($app !== false) == ($key !== false)) {

  			return false;
  		}

  
  		if ($app !== false) {
  			return $this->getAppValues($app);
  		} else {
  			$query = 'SELECT `configvalue`, `appid` FROM `*PREFIX*appconfig` WHERE `configkey` = ?';
  			$result = $this->conn->executeQuery($query, array($key));
  
  			$values = array();
  			while ($row = $result->fetch((\PDO::FETCH_ASSOC))) {
  				$values[$row['appid']] = $row['configvalue'];
  			}
  
  			return $values;

  		}

  	}
  }