if Code.ensure_loaded?(Ecto) do
  defmodule MobileNumberFormat.SegmentedMobileNumber do
    use Ecto.Schema
    import Ecto.Changeset

    @primary_key false

    embedded_schema do
      field :iso_country_code, :string
      field :country_calling_code, :string
      field :national_number, :string
      field :trimmed_national_number_input, :string
      field :international_number, :string
    end

    @fields ~w(iso_country_code country_calling_code national_number international_number)a

    def changeset(mobile, attrs) do
      mobile
      |> cast(attrs, @fields)
      |> validate_and_clean_mobile()
    end

    defp validate_and_clean_mobile(%Ecto.Changeset{changes: %{iso_country_code: _}} = changeset), do:
      do_validate_and_clean_mobile(changeset)

    defp validate_and_clean_mobile(%Ecto.Changeset{changes: %{country_calling_code: _}} = changeset), do:
      do_validate_and_clean_mobile(changeset)

    defp validate_and_clean_mobile(%Ecto.Changeset{changes: %{national_number_user_input: _}} = changeset), do:
      do_validate_and_clean_mobile(changeset)

    defp validate_and_clean_mobile(changeset), do: changeset

    defp do_validate_and_clean_mobile(changeset) do
      parsed_data =
        MobileNumberFormat.parse(%{
          iso_country_code: fetch_field!(changeset, :iso_country_code),
          country_calling_code: fetch_field!(changeset, :country_calling_code),
          national_number: fetch_field!(changeset, :national_number_user_input)
        })

      case parsed_data do
        :invalid_iso_country_code ->
          add_error(changeset, :invalid_iso_country_code, "country is not valid")

        :invalid_country_calling_code ->
          add_error(changeset, :invalid_country_calling_code, "country calling code is not valid")

        :invalid_number ->
          add_error(changeset, :invalid_number, "mobile number is not valid")

        :insufficient_data ->
          raise "unexpected error"

        parsed_data ->
          {:ok, %{
            iso_country_code: iso_country_code,
            country_calling_code: country_calling_code,
            national_number: national_number,
            trimmed_national_number_input: trimmed_national_number_input
          }} = parsed_data

          change(changeset, %{
            iso_country_code: iso_country_code,
            country_calling_code: country_calling_code,
            national_number: national_number,
            national_number_user_input: trimmed_national_number_input
          })
      end
    end
  end
end