defimpl Altstd.Compact, for: MapSet do
  @moduledoc since: "0.1.0"

  @doc since: "0.1.0"
  @spec resolve(MapSet.t(), keyword) :: Altstd.Compact.resolution_t()
  def resolve(object, opts \\ []) do
    case MapSet.size(object) do
      0 ->
        {:reject, object}

      _any ->
        compact_mapset =
          object
          |> Enum.reduce(MapSet.new([]), fn value, acc ->
            resolution =
              value
              |> Altstd.Compact.resolve(opts)

            case resolution do
              {:resolve, resolved_value} ->
                acc
                |> MapSet.put(resolved_value)

              {:reject, _any} ->
                acc

              :reject ->
                acc

              resolved_value ->
                acc
                |> MapSet.put(resolved_value)
            end
          end)

        case MapSet.size(compact_mapset) do
          0 ->
            {:reject, object}

          _any ->
            {:resolve, compact_mapset}
        end
    end
  end

  @doc since: "0.1.0"
  @spec cast(MapSet.t(), keyword) :: Altstd.Compact.t()
  def cast(object, opts \\ []) do
    resolution =
      object
      |> Altstd.Compact.resolve(opts)

    case resolution do
      {:resolve, resolved_value} ->
        resolved_value
        |> List.wrap()

      {:reject, _any} ->
        []

      :reject ->
        []

      resolved_value ->
        resolved_value
        |> List.wrap()
    end
  end
end