defmodule EditorConfig.Properties do
  @moduledoc "Optional typed helpers for resolved EditorConfig property maps."

  @doc """
  Reads `indent_size` as a positive integer or `:tab`.

  ## Examples

      iex> EditorConfig.Properties.indent_size(%{"indent_size" => "2"})
      {:ok, 2}
      iex> EditorConfig.Properties.indent_size(%{"indent_size" => "tab"})
      {:ok, :tab}
  """
  @spec indent_size(map()) :: {:ok, pos_integer() | :tab} | :error
  def indent_size(%{"indent_size" => "tab"}), do: {:ok, :tab}

  def indent_size(%{"indent_size" => value}) do
    case Integer.parse(value) do
      {int, ""} when int > 0 -> {:ok, int}
      _invalid -> :error
    end
  end

  def indent_size(_props), do: :error

  @doc """
  Reads a case-insensitive boolean property.

  ## Examples

      iex> EditorConfig.Properties.boolean(
      ...>   %{"trim_trailing_whitespace" => "TRUE"},
      ...>   "trim_trailing_whitespace"
      ...> )
      {:ok, true}
  """
  @spec boolean(map(), String.t()) :: {:ok, boolean()} | :error
  def boolean(props, key) do
    case Map.fetch(props, key) do
      {:ok, value} -> parse_boolean(String.downcase(value))
      :error -> :error
    end
  end

  defp parse_boolean("true"), do: {:ok, true}
  defp parse_boolean("false"), do: {:ok, false}
  defp parse_boolean(_value), do: :error
end