class CheckGatewayHealthJob < ApplicationJob
  queue_as :default

  def perform
    # Capture stale gateway details BEFORE update_all (update_all bypasses callbacks
    # and would change the scope, so we snapshot the rows first)
    stale_gateway_details = Gateway.where("last_heartbeat_at < ?", 2.minutes.ago)
                                   .where.not(status: "offline")
                                   .pluck(:id, :name, :device_id)

    offline_count = Gateway.where(id: stale_gateway_details.map(&:first)).update_all(status: "offline")

    if offline_count > 0
      Rails.logger.warn("Marked #{offline_count} gateways as offline due to missing heartbeat")

      stale_gateway_details.each do |_id, name, device_id|
        Gateway.dispatch_ntfy("gateway_offline",
          title: "Gateway offline",
          message: "#{name} (#{device_id}) went offline — no heartbeat for 2+ minutes",
          priority: 4,
          tags: [ "rotating_light" ])
      end
    end
  end
end