defmodule Rsh26pool.RoomCloser do
  @moduledoc """
  Periodically closes rooms whose `closes_at` deadline has passed (the "auto
  end" feature). Closing broadcasts to any connected LiveViews so open pages
  transition to the results/grouping view without a manual refresh.
  """
  use GenServer

  require Logger

  alias Rsh26pool.Voting

  @interval :timer.seconds(10)

  def start_link(opts) do
    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
  end

  @impl true
  def init(_opts) do
    schedule()
    {:ok, %{}}
  end

  @impl true
  def handle_info(:sweep, state) do
    sweep()
    schedule()
    {:noreply, state}
  end

  defp sweep do
    for room <- Voting.list_rooms_to_auto_close() do
      case Voting.close_room(room) do
        {:ok, _} ->
          :ok

        other ->
          Logger.warning("RoomCloser failed to close room #{room.id}: #{inspect(other)}")
      end
    end
  end

  defp schedule, do: Process.send_after(self(), :sweep, @interval)
end