area.ex

defmodule Helper.Area do
  @moduledoc false
  defmacro __using__(_) do
    quote do
      import Helper.Area
      @moduledoc false
    end
  end

  defmacro field(name, value) do
    quote do
      defp unquote(name)(), do: unquote(value)
    end
  end

  defmacro builder do
    quote do
      def match?(number) do
        Regex.match?(regex(), number)
      end

      def builder(number) do
        [_ | country] =
          __MODULE__
          |> Module.split
          |> Enum.reverse
        country =
          country
          |> Enum.reverse
          |> Module.concat

        [[_, code, area, number]] = Regex.scan(regex(), number)

        %{
          country: country.country(),
          a2: country.a2(),
          a3: country.a3(),
          international_code: code,
          number: number,
          area_code: area,
          area_name: area_name(),
          area_type: area_type(),
          area_abbreviation: area_abbreviation()
        }
      end

      def build(number) do
        if match?(number) do
          {:ok, builder(number)}
        else
          {:error, "Not a valid phone number."}
        end
      end

      def build!(number) do
        if match?(number) do
          builder(number)
        else
          raise ArgumentError, message: "Not a valid phone number."
        end
      end
    end
  end
end