ex_ihdl_units

defmodule ExIhdlUnits.KilowattHours do
  @behaviour Ecto.Type

  @watts_per_kilowatt 1000

  def type, do: :integer

  def cast(value)
      when is_number(value) do
    {:ok, value}
  end

  def cast(_), do: :error

  def load(data) do
    data_in_kwh = data / @watts_per_kilowatt
    data_in_kwh_int = data_in_kwh |> Kernel.trunc()

    cond do
      data_in_kwh == data_in_kwh_int ->
        {:ok, data_in_kwh_int}

      true ->
        {:ok, data_in_kwh}
    end
  end

  def dump(value) when is_number(value),
    do: {:ok, (value * @watts_per_kilowatt) |> Kernel.trunc()}

  def dump(_), do: :error
end