<?php

namespace Zotlabs\Lib;

use App;

class Config {

	/**
	 * @brief Loads the hub's configuration from database to a cached storage.
	 *
	 * Retrieve a category ($family) of config variables from database to a cached
	 * storage in the global App::$config[$family].
	 *
	 * @param string $family
	 *  The category of the configuration value
	 */
	public static function Load($family, $recursionCounter = 0) {
		if (! array_key_exists($family, App::$config)) {
			App::$config[$family] = [];
		}

		// We typically continue when presented with minor DB issues,
		// but loading the site configuration is more important.

		// Check for query returning false and give it approx 30 seconds
		// to recover if there's a problem. This is intended to fix a
		// rare issue on Galera where temporary sync issues were causing
		// the site encryption keys to be regenerated, which was causing
		// communication issues for members.

		// This code probably belongs at the database layer, but we don't
		// necessarily want to shut the site down for problematic queries
		// caused by bad data. That could be used in a denial of service
		// attack. Those do need to be (and they are) logged.

		if (! array_key_exists('config_loaded', App::$config[$family])) {
			$r = q("SELECT * FROM config WHERE cat = '%s'", dbesc($family));
			if ($r === false && !App::$install) {
				sleep(3);
				$recursionCounter ++;
				if ($recursionCounter > 10) {
					system_unavailable();
				}
				self::Load($family, $recursionCounter);
			}
			elseif (is_array($r)) {
				foreach ($r as $rr) {
					$k = $rr['k'];
					App::$config[$family][$k] = $rr['v'];
				}
				App::$config[$family]['config_loaded'] = true;
			}
		}
	}

	/**
	 * @brief Sets a configuration value for the hub.
	 *
	 * Stores a config value ($value) in the category ($family) under the key ($key).
	 *
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to set
	 * @param mixed $value
	 *  The value to store in the configuration
	 * @return mixed
	 *  Return the set value, or false if the database update failed
	 */
	public static function Set($family, $key, $value) {
		// manage array value
		$dbvalue = ((is_array($value))  ? 'json:' . json_encode($value) : $value);
		$dbvalue = ((is_bool($dbvalue)) ? intval($dbvalue)  : $dbvalue);

		if (self::Get($family, $key) === false || (! self::get_from_storage($family, $key))) {
			$ret = q("INSERT INTO config ( cat, k, v ) VALUES ( '%s', '%s', '%s' ) ",
				dbesc($family),
				dbesc($key),
				dbesc($dbvalue)
			);
			if ($ret) {
				App::$config[$family][$key] = $value;
				$ret = $value;
			}
			return $ret;
		}

		$ret = q("UPDATE config SET v = '%s' WHERE cat = '%s' AND k = '%s'",
			dbesc($dbvalue),
			dbesc($family),
			dbesc($key)
		);

		if ($ret) {
			App::$config[$family][$key] = $value;
			$ret = $value;
		}

		return $ret;
	}

	/**
	 * @brief Get a particular config variable given the category name ($family)
	 * and a key.
	 *
	 * Get a particular config variable from the given category ($family) and the
	 * $key from a cached storage in App::$config[$family]. If a key is found in the
	 * DB but does not exist in local config cache, pull it into the cache so we
	 * do not have to hit the DB again for this item.
	 *
	 * Returns false if not set.
	 *
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to query
	 * @param mixed $default (optional) default false
	 * @return mixed Return value or false on error or if not set
	 */
	public static function Get($family, $key, $default = false) {

		if ((! array_key_exists($family, App::$config)) || (! array_key_exists('config_loaded', App::$config[$family]))) {
			self::Load($family);
		}

		if (array_key_exists('config_loaded', App::$config[$family])) {
			if (! array_key_exists($key, App::$config[$family])) {
				return $default;
			}

			$value = App::$config[$family][$key];

			if (! is_array($value)) {
				if (substr($value, 0, 5) == 'json:') {
					return json_decode(substr($value, 5), true);
				} else if (preg_match('|^a:[0-9]+:{.*}$|s', $value)) {
					// Unserialize in inherently unsafe. Try to mitigate by not
					// allowing unserializing objects. Only kept for backwards
					// compatibility. JSON serialization should be prefered.
					return unserialize($value, array('allowed_classes' => false));
				} else {
					return $value;
				}
			}
			else {
				return $value;
			}
		}

		return $default;
	}

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

		$ret = false;

		if (array_key_exists($family, App::$config) && array_key_exists($key, App::$config[$family])) {
			unset(App::$config[$family][$key]);
		}

		$ret = q("DELETE FROM config WHERE cat = '%s' AND k = '%s'",
			dbesc($family),
			dbesc($key)
		);

		return $ret;
	}


	/**
	 * @brief Returns a record directly from the database configuration storage.
	 *
	 * This function queries directly the database and bypasses the cached storage
	 * from get_config($family, $key).
	 *
	 * @param string $family
	 *  The category of the configuration value
	 * @param string $key
	 *  The configuration key to query
	 * @return mixed
	 */
	private static function get_from_storage($family, $key) {
		$ret = q("SELECT * FROM config WHERE cat = '%s' AND k = '%s' LIMIT 1",
			dbesc($family),
			dbesc($key)
		);

		return $ret;
	}
}