defmodule Nola.Token do
  use GenServer

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

  def lookup(id) do
    with [{_, cred, date}] <- :ets.lookup(__MODULE__.ETS, id),
         IO.inspect(
           "cred: #{inspect(cred)} valid for #{inspect(date)} now #{inspect(DateTime.utc_now())}"
         ),
         d when d > 0 <- DateTime.diff(date, DateTime.utc_now()) do
      {:ok, cred}
    else
      err -> {:error, err}
    end
  end

  def new(cred) do
    GenServer.call(__MODULE__, {:new, cred})
  end

  def init(_) do
    ets =
      :ets.new(__MODULE__.ETS, [:ordered_set, :named_table, :protected, {:read_concurrency, true}])

    {:ok, ets}
  end

  def handle_call({:new, cred}, _, ets) do
    id = Nola.UserTrack.Id.large_id()

    expire =
      DateTime.utc_now()
      |> DateTime.add(15 * 60, :second)

    obj = {id, cred, expire}
    :ets.insert(ets, obj)
    {:reply, {:ok, id}, ets}
  end
end