mio

defmodule Mio do
  def prompt(text) do
    IO.gets(text) |> String.trim()
  end

  def prompt_list(text), do: prompt_list(text, " ")

  def prompt_list(text, delimiter) do
    prompt(text) |> String.trim() |> String.split(delimiter)
  end

  def choice(text, options), do: choice(text, "Make your choice", options)

  def choice(text, prompt_text, options) do
    IO.puts(IO.ANSI.clear_line() <> IO.ANSI.cursor_left(500) <> text)
    size = render_options(options)
    prepare_input_region()

    get_selection(prompt_text <> " (between 1-#{size})", size, options)
  end

  defp render_options(options) do
    size = length(options)

    1..size
    |> Stream.zip(options)
    |> Stream.map(fn {index, option} ->
      case index do
        1 -> IO.ANSI.clear_line() <> format_option(index, option)
        _ -> format_option(index, option)
      end
    end)
    |> Enum.join("   ")
    |> IO.puts()

    size
  end

  defp format_option(index, option) do
    "#{index}) #{option}"
  end

  defp prepare_input_region do
    IO.puts("")
    IO.write(IO.ANSI.cursor_up(1))
  end

  defp get_selection(prompt, size, options), do: get_selection(prompt, size, options, "")

  defp get_selection(prompt, size, options, prefix) do
    output =
      case request_answer(prefix <> prompt) do
        i when 0 <= i and i <= size - 1 ->
          Enum.at(options, i)

        _ ->
          get_selection(
            prompt,
            size,
            options,
            IO.ANSI.cursor_up(1) <> IO.ANSI.clear_line() <> IO.ANSI.cursor_left(500)
          )
      end

    # something here to highlight selection, require 'enter' to fully submit?
    output
  end

  defp request_answer(prompt) do
    case IO.gets(prompt <> ": ") |> Integer.parse() do
      {choice, _} -> choice - 1
      :error -> :error
    end
  end
end