lib/responses/void_payment.ex

defmodule Responses.VoidPayment do
  @derive Jason.Encoder

  defstruct [:links, :action_id]

  def build(%{"_links" => links, "action_id" => action_id}) do
    %__MODULE__{
      links: build_link(links),
      action_id: action_id
    }
  end

  defp build_link(%{"payment" => %{"href" => href}}) do
    %{payment: %{href: href}}
  end
end