working_uart.ex

defmodule UartListener do
  use GenServer

  @serial_port "/dev/cu.usbserial-2210" # e.g., "/dev/ttyUSB0"
  @baud_rate 115200
  # @ic7300_address "94" # Hexadecimal address of IC-7300
  # @controller_address "E0" # Hexadecimal address of the controller (PC)

  # Client
  def start_link(args) do
    GenServer.start_link(__MODULE__, args, name: __MODULE__)
  end

  def send_data(pid, data) do
    GenServer.call(pid, {:send_data, data})
  end

  def init(%{} = _state) do
    {:ok, pid} = Circuits.UART.start_link()
    case Circuits.UART.open(pid, @serial_port, speed: @baud_rate) do 
      :ok -> 
        {:ok, %{pid: pid}}
      {:error, reason} -> {:stop, reason}
    end
  end

  def handle_info({:circuits_uart, _port, data}, state) do 
    process_uart_data(data)
    {:noreply, state}
  end

  defp process_uart_data(data) do 
    data
      |> :erlang.binary_to_list()
      |> Enum.map(&Integer.to_string(&1, 16))
      |> control_command()
  end

  # listen for frequency change
  def control_command(["FE", "FE", "0", "94", "0" | rest]) do
    IO.puts("FREQUENCY")
    info = List.delete_at(rest, length(rest) - 1) |> Enum.reverse |> Enum.join
    IO.puts("ORIGINAL: #{info} | NEW: #{format_frequency(info)}")
  end

  # listen for mode / filter change
  def control_command(["FE", "FE", "0", "94", "1" | rest]) do
    IO.puts("MODE")
    IO.inspect(rest)
  end

  def parse_uart_data(data) do 
    [command | rest] = data
    IO.puts("COMMAND #{command}")
    IO.inspect(rest)
  end

  def handle_info(data, state) do
    {:noreply, state}
  end

  def format_frequency(number) do
    number
    |> String.reverse()
    |> String.graphemes()
    |> Enum.chunk_every(3, 3, :discard)
    |> Enum.map(&Enum.join(&1, ""))
    |> Enum.join(".")
    |> String.reverse()
  end
end