defmodule Microwaveprop.Application do
  # See https://hexdocs.pm/elixir/Application.html
  # for more information on OTP Applications
  @moduledoc false

  use Application

  require Logger

  @impl true
  def start(_type, _args) do
    migrate()

    children = [
      MicrowavepropWeb.Telemetry,
      Microwaveprop.Repo,
      {DNSCluster, query: Application.get_env(:microwaveprop, :dns_cluster_query) || :ignore},
      {Phoenix.PubSub, name: Microwaveprop.PubSub},
      {Oban, Application.fetch_env!(:microwaveprop, Oban)},
      # Start to serve requests, typically the last entry
      MicrowavepropWeb.Endpoint,
      {Task, &ensure_fresh_scores/0}
    ]

    # See https://hexdocs.pm/elixir/Supervisor.html
    # for other strategies and supported options
    opts = [strategy: :one_for_one, name: Microwaveprop.Supervisor]
    Supervisor.start_link(children, opts)
  end

  # Tell Phoenix to update the endpoint configuration
  # whenever the application is updated.
  defp migrate do
    Microwaveprop.Release.migrate()
  end

  # If propagation scores are older than 2 hours, enqueue a grid worker immediately.
  # Covers app restarts, deploys, and missed cron ticks.
  defp ensure_fresh_scores do
    case Microwaveprop.Propagation.latest_valid_time() do
      nil ->
        Logger.info("No propagation scores found, enqueuing grid worker")
        Oban.insert(Microwaveprop.Workers.PropagationGridWorker.new(%{}))

      latest ->
        age_minutes = DateTime.diff(DateTime.utc_now(), latest, :minute)

        if age_minutes > 120 do
          Logger.info("Propagation scores are #{age_minutes}m old, enqueuing grid worker")
          Oban.insert(Microwaveprop.Workers.PropagationGridWorker.new(%{}))
        else
          Logger.info("Propagation scores are #{age_minutes}m old, fresh enough")
        end
    end
  end

  @impl true
  def config_change(changed, _new, removed) do
    MicrowavepropWeb.Endpoint.config_change(changed, removed)
    :ok
  end
end