defmodule Tz.UpdatePeriodically do
  use GenServer
  require Logger
  alias Tz.HTTP
  alias Tz.Updater

  defp maybe_recompile() do
    Logger.debug("Tz is checking for IANA time zone database updates")

    Updater.maybe_recompile()
  end

  def start_link(_) do
    HTTP.get_http_client!()

    GenServer.start_link(__MODULE__, %{})
  end

  def init(state) do
    maybe_recompile()

    {:ok, state}
  end

  def handle_info(:work, state) do
    maybe_recompile()

    schedule_work()
    {:noreply, state}
  end

  defp schedule_work() do
    Process.send_after(self(), :work, 24 * 60 * 60 * 1000) # In 24 hours
  end
end