<?php

namespace Code\Lib;

use App;

/**
 * @brief Class for handling observer's config.
 *
 * <b>XConfig</b> is comparable to <i>PConfig</i>, except that it uses <i>xchan</i>
 * (an observer hash) as an identifier.
 *
 * <b>XConfig</b> is used for observer specific configurations and takes a
 * <i>xchan</i> as identifier.
 * The storage is of size MEDIUMTEXT.
 *
 * @code{.php}$var = Code\Lib\XConfig::Get('xchan', 'category', 'key');
 * // with default value for non existent key
 * $var = Code\Lib\XConfig::Get('xchan', 'category', 'unsetkey', 'defaultvalue');@endcode
 *
 * The old (deprecated?) way to access a XConfig value is:
 * @code{.php}$observer = App::get_observer_hash();
 * if ($observer) {
 *     $var = get_xconfig($observer, 'category', 'key');
 * }@endcode
 */
class XConfig
{

    /**
     * @brief Loads a full xchan's configuration into a cached storage.
     *
     * All configuration values of the given observer hash are stored in global
     * cache which is available under the global variable App::$config[$xchan].
     *
     * @param string $xchan
     *  The observer's hash
     * @return bool Returns false if xchan is not set
     */
    public static function Load($xchan): bool
    {

        if (! $xchan) {
            return false;
        }

        if (! array_key_exists($xchan, App::$config)) {
            App::$config[$xchan] = [];
        }

        $r = q(
            "SELECT * FROM xconfig WHERE xchan = '%s'",
            dbesc($xchan)
        );

        if ($r) {
            foreach ($r as $rr) {
                $k = $rr['k'];
                $c = $rr['cat'];
                if (! array_key_exists($c, App::$config[$xchan])) {
                    App::$config[$xchan][$c] = [];
                    App::$config[$xchan][$c]['config_loaded'] = true;
                }
                App::$config[$xchan][$c][$k] = $rr['v'];
            }
            return true;
        }
        return false;
    }

    /**
     * @brief Get a particular observer's config variable given the category
     * name ($family) and a key.
     *
     * Get a particular observer's config value from the given category ($family)
     * and the $key from a cached storage in App::$config[$xchan].
     *
     * Returns false if not set.
     *
     * @param string $xchan
     *  The observer's hash
     * @param string $family
     *  The category of the configuration value
     * @param string $key
     *  The configuration key to query
     * @param bool $default (optional) default false
     * @return mixed Stored $value or false if it does not exist
     */
    public static function Get($xchan, $family, $key, $default = false)
    {

        if (! $xchan) {
            return $default;
        }

        if (! array_key_exists($xchan, App::$config)) {
            load_xconfig($xchan);
        }

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

        return unserialise(App::$config[$xchan][$family][$key]);
    }

    /**
     * @brief Sets a configuration value for an observer.
     *
     * Stores a config value ($value) in the category ($family) under the key ($key)
     * for the observer's $xchan hash.
     *
     * @param string $xchan
     *  The observer's hash
     * @param string $family
     *  The category of the configuration value
     * @param string $key
     *  The configuration key to set
     * @param mixed $value
     *  The value to store
     * @return mixed Stored $value or false
     */
    public static function Set($xchan, $family, $key, $value)
    {

        // manage array value
        $dbvalue = ((is_array($value))  ? serialise($value) : $value);
        $dbvalue = ((is_bool($dbvalue)) ? intval($dbvalue)  : $dbvalue);

        if (self::Get($xchan, $family, $key) === false) {
            if (! array_key_exists($xchan, App::$config)) {
                App::$config[$xchan] = [];
            }
            if (! array_key_exists($family, App::$config[$xchan])) {
                App::$config[$xchan][$family] = [];
            }

            $ret = q(
                "INSERT INTO xconfig ( xchan, cat, k, v ) VALUES ( '%s', '%s', '%s', '%s' )",
                dbesc($xchan),
                dbesc($family),
                dbesc($key),
                dbesc($dbvalue)
            );
        } else {
            $ret = q(
                "UPDATE xconfig SET v = '%s' WHERE xchan = '%s' and cat = '%s' AND k = '%s'",
                dbesc($dbvalue),
                dbesc($xchan),
                dbesc($family),
                dbesc($key)
            );
        }

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

        if ($ret) {
            return $value;
        }

        return $ret;
    }

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

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

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

        return $ret;
    }
}