bran

defmodule BRAN.Banks.Util do
  @moduledoc """
  Documentation for `BRAN.Banks.Util`.
  """
  def is_valid_agency_number?(agency_number), do: length(agency_number) == 4

  @spec is_valid_numeric_digit?(String.t() | Integer.t()) ::
          {:not_valid, :non_numeric_digit} | {:ok, integer}
  def is_valid_numeric_digit?(digit) when is_integer(digit), do: {:ok, digit}

  def is_valid_numeric_digit?(digit) do
    case Integer.parse(digit) do
      {parsed_digit, _rest} ->
        {:ok, parsed_digit}

      _ ->
        {:not_valid, :non_numeric_digit}
    end
  end
end