defmodule BACnet.Protocol.Services.GetAlarmSummary do
  @moduledoc """
  This module represents the BACnet Get Alarm Summary service.

  The Get Alarm Summary service is used to get a list of active alarms from a device.
  Active alarm refers to all abnormal events.

  Service Description (ASHRAE 135):
  > The GetAlarmSummary service is used by a client BACnet-user to obtain a summary of "active alarms." The term "active
  > alarm" refers to BACnet standard objects that have an Event_State property whose value is not equal to NORMAL and a
  > Notify_Type property whose value is ALARM. The GetEnrollmentSummary service provides a more sophisticated approach
  > with various kinds of filters.
  """

  alias BACnet.Protocol
  alias BACnet.Protocol.Constants

  require Constants

  @behaviour Protocol.Services.Behaviour

  # TODO: Docs
  # TODO: Add Service Procedure to docs

  @type t :: %__MODULE__{}

  @fields []
  @enforce_keys @fields
  defstruct @fields

  @service_name Constants.macro_assert_name(
                  :confirmed_service_choice,
                  :get_alarm_summary
                )

  @doc """
  Get the service name atom.
  """
  @spec get_name() :: atom()
  def get_name(), do: @service_name

  @doc """
  Whether the service is of type confirmed or unconfirmed.
  """
  @spec is_confirmed() :: true
  def is_confirmed(), do: true

  @doc """
  Converts the given Confirmed Service Request into a Get Alarm Summary Service.
  """
  @spec from_apdu(Protocol.APDU.ConfirmedServiceRequest.t()) ::
          {:ok, t()} | {:error, term()}
  def from_apdu(
        %Protocol.APDU.ConfirmedServiceRequest{
          service: @service_name
        } = _request
      ) do
    ack = %__MODULE__{}
    {:ok, ack}
  end

  def from_apdu(%Protocol.APDU.ConfirmedServiceRequest{} = _request) do
    {:error, :invalid_request}
  end

  @doc """
  Get the Confirmed Service request for the given Get Alarm Summary Service.

  See the `BACnet.Protocol.Services.Protocol` function documentation for more information.
  """
  @spec to_apdu(t(), Keyword.t()) ::
          {:ok, Protocol.APDU.ConfirmedServiceRequest.t()}
          | {:error, term()}
  def to_apdu(%__MODULE__{} = _service, request_data) do
    req = %Protocol.APDU.ConfirmedServiceRequest{
      segmented_response_accepted: request_data[:segmented_response_accepted] || true,
      max_segments: request_data[:max_segments] || :more_than_64,
      max_apdu:
        request_data[:max_apdu] ||
          Constants.macro_by_name(:max_apdu_length_accepted_value, :octets_1476),
      invoke_id: request_data[:invoke_id] || 0,
      sequence_number: nil,
      proposed_window_size: nil,
      service: @service_name,
      parameters: []
    }

    {:ok, req}
  end

  defimpl Protocol.Services.Protocol do
    alias BACnet.Protocol
    alias BACnet.Protocol.Constants
    require Constants

    @spec get_name(@for.t()) :: atom()
    def get_name(%@for{} = _service), do: @for.get_name()

    @spec is_confirmed(@for.t()) :: boolean()
    def is_confirmed(%@for{} = _service), do: @for.is_confirmed()

    @spec to_apdu(@for.t(), Keyword.t()) ::
            {:ok, Protocol.APDU.ConfirmedServiceRequest.t()}
            | {:error, term()}
    def to_apdu(%@for{} = service, request_data), do: @for.to_apdu(service, request_data)
  end
end