discourse/app/jobs/scheduled/pending_flags_reminder.rb

require_dependency 'flag_query'

module Jobs

  class PendingFlagsReminder < Jobs::Scheduled

    every 1.hour

    def execute(args)
      if SiteSetting.notify_about_flags_after > 0 &&
          PostAction.flagged_posts_count > 0 &&
          flag_ids.size > 0 && last_notified_id.to_i < flag_ids.max

        mentions = active_moderator_usernames.size > 0 ?
          "@#{active_moderator_usernames.join(', @')} " : ""

        PostCreator.create(
          Discourse.system_user,
          target_group_names: Group[:staff].name,
          archetype: Archetype.private_message,
          subtype: TopicSubtype.system_message,
          title: I18n.t('flags_reminder.subject_template', { count: PostAction.flagged_posts_count }),
          raw: mentions + I18n.t('flags_reminder.flags_were_submitted', { count: SiteSetting.notify_about_flags_after })
        )

        self.last_notified_id = flag_ids.max
      end

      true
    end

    def flag_ids
      @_flag_ids ||= FlagQuery.flagged_post_actions('active')
        .where('post_actions.created_at < ?', SiteSetting.notify_about_flags_after.to_i.hours.ago)
        .pluck(:id)
    end

    def last_notified_id
      $redis.get(self.class.last_notified_key)&.to_i
    end

    def last_notified_id=(arg)
      $redis.set(self.class.last_notified_key, arg)
    end

    def self.last_notified_key
      "last_notified_pending_flag_id"
    end

    def active_moderator_usernames
      @_active_moderator_usernames ||=
        User.where(moderator: true)
          .human_users
          .order('last_seen_at DESC')
          .limit(3)
          .pluck(:username)
    end

  end

end