snapex7

defmodule CliLowLevelTest do
  use ExUnit.Case, async: false
  doctest Snapex7

  @s7_msg <<0x32, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x0E, 0x00, 0x00, 0x04, 0x01, 0x12, 0x0A,
            0x10, 0x02, 0x00, 0x04, 0x00, 0x01, 0x84, 0x00, 0x00, 0x10>>
  @s7_response <<0x32, 0x03, 0x00, 0x00, 0x01, 0x00, 0x00, 0x02, 0x00, 0x08, 0x00, 0x00, 0x04,
                 0x01, 0xFF, 0x04, 0x00, 0x20, 0x42, 0xCA, 0x00, 0x00, 0x00, 0x10>>

  setup do
    snap7_dir = :code.priv_dir(:snapex7) |> List.to_string()
    System.put_env("LD_LIBRARY_PATH", snap7_dir)
    System.put_env("DYLD_LIBRARY_PATH", snap7_dir)
    executable = :code.priv_dir(:snapex7) ++ ~c"/s7_client.o"

    port =
      Port.open({:spawn_executable, executable}, [
        {:args, []},
        {:packet, 2},
        :use_stdio,
        :binary,
        :exit_status
      ])

    msg = {:connect_to, {"192.168.0.1", 0, 1}}
    send(port, {self(), {:command, :erlang.term_to_binary(msg)}})

    status =
      receive do
        {_, {:data, <<?r, response::binary>>}} ->
          :erlang.binary_to_term(response)
      after
        10000 ->
          :error
      end

    %{port: port, status: status}
  end

  test "handle_iso_exchange_buffer", state do
    case state.status do
      :ok ->
        # {size, S7 pdu}
        msg = {:iso_exchange_buffer, {String.length(@s7_msg), @s7_msg}}
        send(state.port, {self(), {:command, :erlang.term_to_binary(msg)}})

        c_response =
          receive do
            {_, {:data, <<?r, response::binary>>}} ->
              :erlang.binary_to_term(response)

            x ->
              IO.inspect(x)
              :error
          after
            1000 ->
              # Not sure how this can be recovered
              exit(:port_timed_out)
          end

        assert {:ok, @s7_response} == c_response

      _ ->
        IO.puts("(#{__MODULE__}) Not connected")
    end
  end
end