discourse/app/jobs/regular/delete_topic.rb

module Jobs
  class DeleteTopic < Jobs::Base

    def execute(args)
      topic_timer = TopicTimer.find_by(id: args[:topic_timer_id] || args[:topic_status_update_id])

      topic = topic_timer&.topic

      if topic_timer.blank? || topic.blank? || topic_timer.execute_at > Time.zone.now
        return
      end

      if Guardian.new(topic_timer.user).can_delete?(topic)
        first_post = topic.ordered_posts.first
        PostDestroyer.new(topic_timer.user, first_post, { context: I18n.t("topic_statuses.auto_deleted_by_timer") }).destroy
        topic_timer.trash!(Discourse.system_user)
      end
    end

  end
end