<?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 qbank_comment\privacy;

use core_privacy\local\metadata\collection;
use core_privacy\local\request\approved_contextlist;
use core_privacy\local\request\contextlist;
use core_privacy\local\request\userlist;
use core_privacy\local\request\approved_userlist;

/**
 * Privacy Subsystem for qbank_comment.
 *
 * @package    qbank_comment
 * @copyright  2021 Catalyst IT Australia Pty Ltd
 * @author     Safat Shahin <safatshahin@catalyst-au.net>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class provider implements
        // The qbank_comment stores user provided data.
        \core_privacy\local\metadata\provider,
        \core_privacy\local\request\core_userlist_provider,
        // The qbank_comment provides data directly to core.
        \core_privacy\local\request\plugin\provider {

    /**
     * Returns meta data about this system.
     *
     * @param collection $collection
     * @return collection
     */
    public static function get_metadata(collection $collection): collection {
        return $collection->add_subsystem_link('core_comment', [], 'privacy:metadata:core_comment');
    }

    /**
     * Get the list of contexts that contain user information for the specified user.
     *
     * @param int $userid
     * @return contextlist
     */
    public static function get_contexts_for_userid(int $userid): contextlist {
        $contextlist = new contextlist();

        $sql = "SELECT contextid
                  FROM {comments}
                 WHERE component = :component
                       AND userid = :userid";
        $params = [
                'area' => 'question',
                'component' => 'qbank_comment',
                'userid' => $userid
        ];

        $contextlist->add_from_sql($sql, $params);
        return $contextlist;
    }

    /**
     * Get the list of users within a specific context.
     *
     * @param userlist $userlist The userlist containing the list of users who have data in this context/plugin combination.
     */
    public static function get_users_in_context(userlist $userlist) {
        $context = $userlist->get_context();

        $params = [
                'contextid' => $context->id,
                'area' => 'question',
                'component' => 'qbank_comment'
        ];

        $sql = "SELECT userid as userid
                  FROM {comments}
                 WHERE component = :component
                       AND contextid = :contextid";

        $userlist->add_from_sql('userid', $sql, $params);
    }

    /**
     * Export all user data for the specified user, in the specified contexts.
     *
     * @param approved_contextlist $contextlist
     */
    public static function export_user_data(approved_contextlist $contextlist) {
        $contexts = $contextlist->get_contexts();
        foreach ($contexts as $context) {
            \core_comment\privacy\provider::export_comments(
                    $context,
                    'qbank_comment',
                    'question',
                    0,
                    []
            );
        }
    }

    /**
     * Delete all data for all users in the specified context.
     *
     * @param \context $context
     */
    public static function delete_data_for_all_users_in_context(\context $context) {
        \core_comment\privacy\provider::delete_comments_for_all_users($context, 'qbank_comment');
    }

    /**
     * Delete multiple users within a single context.
     *
     * @param approved_userlist $userlist The approved context and user information to delete information for.
     */
    public static function delete_data_for_users(approved_userlist $userlist) {
        \core_comment\privacy\provider::delete_comments_for_users($userlist, 'qbank_comment');
    }

    /**
     * Delete all user data for the specified user, in the specified contexts.
     *
     * @param approved_contextlist $contextlist
     */
    public static function delete_data_for_user(approved_contextlist $contextlist) {
        \core_comment\privacy\provider::delete_comments_for_user($contextlist, 'qbank_comment');
    }

}
