defmodule AudioBuffer do
  use GenServer

  def start_link(_opts) do
    GenServer.start_link(__MODULE__, %{}, name: __MODULE__)
  end

  def append(ref, chunk) do
    GenServer.cast(__MODULE__, {:append, ref, chunk})
  end

  def get_and_clear(ref) do
    GenServer.call(__MODULE__, {:get_and_clear, ref})
  end

  def flush_all() do
    GenServer.call(__MODULE__, :flush_all)
  end

  def init(state), do: {:ok, state}

  def handle_cast({:append, ref, chunk}, state) do
    updated = Map.update(state, ref, [chunk], fn chunks -> chunks ++ [chunk] end)
    {:noreply, updated}
  end

  def handle_call({:get_and_clear, ref}, _from, state) do
    {chunks, new_state} = Map.pop(state, ref, [])
    {:reply, chunks, new_state}
  end

  def handle_call(:flush_all, _from, state) do
    {:reply, state, %{}}
  end
end