singyeong

defmodule Singyeong.Consumer do
  use ConsumerSupervisor

  @type event() ::
      {:send, String.t() | nil, term()}
      | {:broadcast, String.t() | nil, term()}
      | {:queue, String.t(), String.t() | nil, term()}
      | {:queue_confirm, String.t()}

  @callback handle_event(event()) :: term()

  def start_link(mod) do
    ConsumerSupervisor.start_link __MODULE__, mod
  end

  def init(mod) do
    children =
      [
        %{
          id: mod,
          start: {mod, :start_link, []},
          restart: :transient,
        },
      ]
    opts =
      [
        strategy: :one_for_one,
        subscribe_to: [Singyeong.Producer],
      ]

    ConsumerSupervisor.init children, opts
  end

  def handle_events(_events, _from, state) do
    {:noreply, [], state}
  end

  defmacro __using__(_) do
    quote do
      @behaviour Singyeong.Consumer

      alias Singyeong.Consumer
      require Logger

      def start_link(event) do
        __MODULE__.handle_event event
      end

      def child_spec(_) do
        spec =
          %{
            id: __MODULE__,
            start: {__MODULE__, :start_link, []},
          }

        Supervisor.child_spec spec, []
      end

      def handle_event(_), do: :ok

      defoverridable handle_event: 1, child_spec: 1
    end
  end
end