ecto_foundationdb

defmodule EctoFoundationDB.Sandbox.Sandboxer do
  @moduledoc false
  use GenServer

  defstruct [:db]

  def start_link(init_arg) do
    GenServer.start_link(__MODULE__, init_arg)
  end

  def get_or_create_test_db(pid, subdir) do
    GenServer.call(pid, {:get_or_create_test_db, subdir}, 60_000)
  end

  @impl true
  def init(_init_arg) do
    {:ok, %__MODULE__{}}
  end

  @impl true
  def handle_call({:get_or_create_test_db, subdir}, _from, state = %__MODULE__{db: nil}) do
    # :erlfdb_sandbox.open/0 has a wide-open receive block, so we have to insulate
    # it from the GenServer
    task = Task.async(fn -> :erlfdb_sandbox.open(subdir) end)
    db = Task.await(task)

    {:reply, db, %__MODULE__{state | db: db}}
  end

  def handle_call({:get_or_create_test_db, _}, _from, state = %__MODULE__{db: db}) do
    {:reply, db, state}
  end
end