<?php
namespace Friendica\Core;

use dba;
use dbm;

/**
 * @file include/Core/PConfig.php
 * @brief contains the class with methods for the management
 * of the user configuration
 */

/**
 * @brief Management of user configuration storage
 * Note:
 * Please do not store booleans - convert to 0/1 integer values
 * The PConfig::get() functions return boolean false for keys that are unset,
 * and this could lead to subtle bugs.
 */
class PConfig {

	private static $in_db;

	/**
	 * @brief Loads all configuration values of a user's config family into a cached storage.
	 *
	 * All configuration values of the given user are stored in global cache
	 * which is available under the global variable $a->config[$uid].
	 *
	 * @param string $uid
	 *  The user_id
	 * @param string $family
	 *  The category of the configuration value
	 * @return void
	 */
	public static function load($uid, $family) {
		$a = get_app();

		$r = dba::select('pconfig', array('v', 'k'), array('cat' => $family, 'uid' => $uid));
		if (dbm::is_result($r)) {
			while ($rr = dba::fetch($r)) {
				$k = $rr['k'];
				$a->config[$uid][$family][$k] = $rr['v'];
				self::$in_db[$uid][$family][$k] = true;
			}
		} else if ($family != 'config') {
			// Negative caching
			$a->config[$uid][$family] = "!<unset>!";
		}
		dba::close($r);
	}

	/**
	 * @brief Get a particular user's config variable given the category name
	 * ($family) and a key.
	 *
	 * Get a particular user's config value from the given category ($family)
	 * and the $key from a cached storage in $a->config[$uid].
	 *
	 * @param string $uid
	 *  The user_id
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to query
	 * @param mixed $default_value optional
	 *  The value to return if key is not set (default: null)
	 * @param boolean $refresh optional
	 *  If true the config is loaded from the db and not from the cache (default: false)
	 * @return mixed Stored value or null if it does not exist
	 */
	public static function get($uid, $family, $key, $default_value = null, $refresh = false) {

		$a = get_app();

		if (!$refresh) {
			// Looking if the whole family isn't set
			if (isset($a->config[$uid][$family])) {
				if ($a->config[$uid][$family] === '!<unset>!') {
					return $default_value;
				}
			}

			if (isset($a->config[$uid][$family][$key])) {
				if ($a->config[$uid][$family][$key] === '!<unset>!') {
					return $default_value;
				}
				return $a->config[$uid][$family][$key];
			}
		}

		$ret = dba::select('pconfig', array('v'), array('uid' => $uid, 'cat' => $family, 'k' => $key), array('limit' => 1));
		if (dbm::is_result($ret)) {
			$val = (preg_match("|^a:[0-9]+:{.*}$|s", $ret['v']) ? unserialize($ret['v']) : $ret['v']);
			$a->config[$uid][$family][$key] = $val;
			self::$in_db[$uid][$family][$key] = true;

			return $val;
		} else {
			$a->config[$uid][$family][$key] = '!<unset>!';
			self::$in_db[$uid][$family][$key] = false;

			return $default_value;
		}
	}

	/**
	 * @brief Sets a configuration value for a user
	 *
	 * Stores a config value ($value) in the category ($family) under the key ($key)
	 * for the user_id $uid.
	 *
	 * @note Please do not store booleans - convert to 0/1 integer values!
	 *
	 * @param string $uid
	 *  The user_id
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to set
	 * @param string $value
	 *  The value to store
	 * @return mixed Stored $value or false
	 */
	public static function set($uid, $family, $key, $value) {

		$a = get_app();

		// We store our setting values in a string variable.
		// So we have to do the conversion here so that the compare below works.
		// The exception are array values.
		$dbvalue = (!is_array($value) ? (string)$value : $value);

		$stored = self::get($uid, $family, $key, null, true);

		if (($stored === $dbvalue) && self::$in_db[$uid][$family][$key]) {
			return true;
		}

		$a->config[$uid][$family][$key] = $dbvalue;

		// manage array value
		$dbvalue = (is_array($value) ? serialize($value) : $dbvalue);

		dba::update('pconfig', array('v' => $dbvalue), array('uid' => $uid, 'cat' => $family, 'k' => $key), true);

		if ($ret) {
			self::$in_db[$uid][$family][$key] = true;
			return $value;
		}
		return $ret;
	}

	/**
	 * @brief Deletes the given key from the users's configuration.
	 *
	 * Removes the configured value from the stored cache in $a->config[$uid]
	 * and removes it from the database.
	 *
	 * @param string $uid The user_id
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to delete
	 * @return mixed
	 */
	public static function delete($uid,$family,$key) {

		$a = get_app();

		if (x($a->config[$uid][$family], $key)) {
			unset($a->config[$uid][$family][$key]);
			unset(self::$in_db[$uid][$family][$key]);
		}

		$ret = dba::delete('pconfig', array('uid' => $uid, 'cat' => $family, 'k' => $key));

		return $ret;
	}
}
