defmodule Saxon.Parsers.INTEGER do
  defstruct buffer: [], attributes: %{}

  def new(attributes \\ %{}), do: %__MODULE__{attributes: attributes}

  def update(%__MODULE__{buffer: buffer} = parser, chunk) do
    %{parser | buffer: [buffer, chunk]}
  end

  def parse(%__MODULE__{buffer: buffer, attributes: attributes}) do
    buffer = buffer |> IO.iodata_to_binary() |> String.trim()
    parse(buffer, attributes)
  end

  defp parse("", attributes) do
    {:ok, nil, attributes}
  end

  defp parse(buffer, attributes) do
    try do
      result = buffer |> String.to_integer()
      {:ok, result, attributes}
    rescue
      _ -> {:error, :invalid_format, buffer}
    end
  end
end