public function get_next_stage() {
        if ($this->oneclickbackup) {
            // Its a one click backup.
            // The default filename is backup.mbz, this normally gets set to something useful in the confirmation stage.
            // because we skipped that stage we must manually set this to a useful value.
            $tasks = $this->ui->get_tasks();
            foreach ($tasks as $task) {
                if ($task instanceof backup_root_task) {
                    // Find the filename setting.
                    $setting = $task->get_setting('filename');
                    if ($setting) {
                        // Use the helper objects to get a useful name.
                        $filename = backup_plan_dbops::get_default_backup_filename(
                            $this->ui->get_format(),
                            $this->ui->get_type(),
                            $this->ui->get_controller_id(),
                            $this->ui->get_setting_value('users'),
                            $this->ui->get_setting_value('anonymize')
                        );
                        $setting->set_value($filename);
                    }
                }
            }
            return backup_ui::STAGE_FINAL;
        }
        return parent::get_next_stage();
    }