defmodule Dexcord.FakeGateway.TestHandler do
  @moduledoc false
  # A `Dexcord.Handler` that relays every dispatched event to a subscribed test
  # process as `{:handler_event, {name, data}}`. The sink pid lives in
  # `:persistent_term` so the stateless handler module can find it; each test calls
  # `subscribe/1` in setup.

  @behaviour Dexcord.Handler

  @key {__MODULE__, :sink}

  def subscribe(pid), do: :persistent_term.put(@key, pid)

  @impl true
  def handle_event(event) do
    case :persistent_term.get(@key, nil) do
      nil -> :ok
      pid -> send(pid, {:handler_event, event})
    end
  end
end