defmodule Ffmpeg do
  @moduledoc false
  def audio_stream!(stream) do
    # read from stdin and write to stdout
    proc_stream = Exile.stream!(~w(ffmpeg -i - -f mp3 -))

    spawn_link(fn ->
      Stream.into(stream, proc_stream)
      |> Stream.run()
    end)

    proc_stream
  end

  def run do
    # :observer.start()
    # :timer.sleep(10000)

    IO.puts("Starting")

    {time, _} =
      :timer.tc(fn ->
        Exile.stream!(~w(ffmpeg -i - -f mp3 -), input: File.stream!("music_video.mkv", [], 65535))
        |> Stream.into(File.stream!("music.mp3"))
        |> Stream.run()
      end)

    IO.puts("=============== TIME: #{time / 1000}")
  end

  def test_stderr do
    Exile.stream!(~w(ffmpeg -y -i pipe:0 -f mp3 pipe:1),
      input: File.stream!("danse.mkv", [], 65535),
      use_stderr: true
    )
    |> Stream.transform(
      fn ->
        File.open!("music.mp3", [:write, :binary])
      end,
      fn elem, file ->
        case elem do
          {:stdout, data} ->
            :ok = IO.binwrite(file, data)

          {:stderr, msg} ->
            :ok = IO.write(msg)
        end

        {[], file}
      end,
      fn file ->
        :ok = File.close(file)
      end
    )
    |> Stream.run()
  end

  def test do
    script = """
    for i in {1..10}; do
      echo "foo ${i}"
      echo "bar ${i}" >&2
    done
    """

    Exile.stream!(["sh", "-c", script], use_stderr: true)
    |> Enum.each(fn {stream, lines} ->
      String.split(lines, "\n", trim: true)
      |> Enum.each(fn line -> IO.puts("#{stream}: #{line}") end)
    end)
  end

  def random do
    cmd = ["sh", "-c", "head -c 1000000000 < /dev/urandom"]
    IO.inspect(cmd)
    {:ok, s} = Exile.Process.start_link(cmd)
    :ok = loop(s)
    Exile.Process.stop(s)
  end

  defp loop(s) do
    case Exile.Process.read(s) do
      {:ok, data} ->
        IO.inspect(IO.iodata_length(data), label: :read)
        loop(s)

      {:eof, _} ->
        :ok
    end
  end
end