<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace mod_adaptivequiz\local\report\users_attempts\user_preferences;

/**
 * Provides methods for storing and fetching of the report user preferences from the storage.
 *
 * Operates on user session as well to avoid unnecessary database queries.
 *
 * @package    mod_adaptivequiz
 * @copyright  2022 Vitaly Potenko <potenkov@gmail.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
final class user_preferences_repository {

    /**
     * @var string Name of the preference.
     */
    private const PREFERENCE_NAME = 'adaptivequiz_users_attempts_report';

    /**
     * Stores the given preferences object in available storages.
     *
     * @param user_preferences $prefs
     */
    public static function save(user_preferences $prefs): void {
        global $SESSION;

        $prefsarr = $prefs->as_array();

        $SESSION->flextableextra[self::PREFERENCE_NAME] = $prefsarr;
        set_user_preference(self::PREFERENCE_NAME, json_encode($prefsarr));
    }

    /**
     * Instantiates user preferences from available storages or default.
     *
     * @return user_preferences
     */
    public static function get(): user_preferences {
        global $SESSION;

        if (!empty($SESSION->flextableextra[self::PREFERENCE_NAME])) {
            return user_preferences::from_array($SESSION->flextableextra[self::PREFERENCE_NAME]);
        }

        if (!$json = get_user_preferences(self::PREFERENCE_NAME)) {
            return user_preferences::defaults();
        }

        return user_preferences::from_array(json_decode($json, true));
    }
}