moodle-local_course_completion_checker/classes/observer.php

<?php

namespace local_course_completion_checker;

defined('MOODLE_INTERNAL') || die();

class observer
{
    public static function check_course_completion(\mod_quiz\event\attempt_submitted $event)
    {
        global $DB;

        $userid = $event->relateduserid;
        $courseid = $event->courseid;

        $completion = new \completion_info($event->get_course());

        if (!$completion->is_enabled()) {
            return;
        }

        $completion->update_state();
        \core\notification::add("Course completion status updated for user $userid in course $courseid.", \core\output\notification::NOTIFY_SUCCESS);
    }
}