defmodule PotionIngredients.CQRS.Handler do
  alias Plug.Conn

  def handle(output, presenter, conn) do
    output
    |> case do
      {:ok, status, body} ->
        handle_success(conn, presenter, status, body)

      {:error, status, reason} ->
        handle_error(conn, presenter, status, reason)
    end
  end

  defp handle_success(conn, presenter, status, body)
       when is_atom(status) and (is_map(body) or is_list(body)) do
    conn
    |> Conn.put_resp_header("Content-Type", "application/json")
    |> Conn.resp(
      status,
      Poison.encode!(presenter.render("index.json", Casefy.camel_case(body)))
    )
    |> Conn.halt()
  end

  defp handle_error(conn, presenter, status, reason) when is_atom(status) and is_map(reason) do
    conn
    |> Conn.put_resp_header("Content-Type", "application/json")
    |> Conn.resp(
      status,
      Poison.encode!(presenter.render("error.json", Casefy.camel_case(reason)))
    )
    |> Conn.halt()
  end
end