defmodule ArcadiaCloud.Provisioning.Steps.Echo do
  @moduledoc """
  Trivial proof-of-concept step. Reads `:echo_value` from saga inputs and
  copies it to context under a step-specific key so subsequent steps can
  see it. Used by engine smoke tests only — not for real workloads.
  """

  @behaviour ArcadiaCloud.Provisioning.Step

  alias ArcadiaCloud.Provisioning.SagaState

  @impl true
  def name, do: "echo"

  @impl true
  def execute(state) do
    value = SagaState.get_input(state, :echo_value) || "default"
    {:ok, SagaState.put_output(state, "echoed_at_step_#{state.step_idx}", value)}
  end

  @impl true
  def compensate(state) do
    # Echo is reversible: we can simply forget what we wrote. No real
    # side-effects to undo.
    _ = state
    :ok
  end
end