minipeg

defmodule Minipeg.Formatter do
  use Minipeg.Types

  alias Minipeg.{Failure, Input, Success}

  @moduledoc ~S"""
  Utility for using with the function form of the `debug` combinator.

  """

  @typep format_t :: :short | :medium | :long
  @typep subject_t :: result_t() | Input.t | {Input.t, result_t()}

  @spec fmt(format_t(), subject_t(), name_t?()) :: binary()
  def fmt(type, subject, label \\ nil)
  def fmt(type, {input, result}, label) do
    prefix = if label, do: [label], else: []
    prefix ++ [
      fmt(type, input, nil), fmt(type, result, nil)
    ] |> Enum.join("\n")
  end
  def fmt(type, %Failure{} = failure, label), do: _fmt_failure(type, failure, label)
  def fmt(type, %Input{} = input, label), do: _fmt_input(type, input, label)
  def fmt(type, %Success{} = success, label), do: _fmt_success(type, success, label)

  def format(type, label \\ nil) do
    &fmt(type, {&1, &2}, label)
  end

  @spec _fmt_failure(format_t(), Failure.t, name_t?()) :: binary()
  defp _fmt_failure(type, failure, label)
  defp _fmt_failure(:short, %Failure{reason: reason}, label) do
    [_labelled("Failure", label), reason] |> Enum.join
  end
  # defp _fmt_failure(:medium, failure, label) do
  #   raise "Not yet implemented"
  # end
  # defp _fmt_failure(:long, failure, label) do
  #   raise "Not yet implemented"
  # end

  @spec _fmt_input(format_t(), Input.t, name_t?()) :: binary()
  defp _fmt_input(type, input, label)
  defp _fmt_input(:short, %Input{} = input, label) do
    [_labelled("Input", label), input.col, ",", input.lnb, ">", input.input] |> Enum.join
  end
  # defp _fmt_input(:medium, input, label) do
  #   raise "Not yet implemented"
  # end
  # defp _fmt_input(:long, input, label) do
  #   raise "Not yet implemented"
  # end

  @spec _fmt_success(format_t(), Success.t, name_t?()) :: binary()
  defp _fmt_success(type, success, label)
  defp _fmt_success(:short, %Success{ast: ast}, label) do
    [_labelled("Success", label), inspect(ast)] |> Enum.join
  end
  # defp _fmt_success(:medium, success, label) do
  #   raise "Not yet implemented"
  # end
  # defp _fmt_success(:long, success, label) do
  #   raise "Not yet implemented"
  # end

  @spec _labelled(binary(), name_t?()) :: binary()
  defp _labelled(origin, label)
  defp _labelled(origin, nil), do: "#{origin}: "
  defp _labelled(origin, label), do: "#{origin}(#{label}): "
end
# SPDX-License-Identifier: Apache-2.0