defmodule Microwaveprop.Workers.QsoWeatherEnqueueWorker do
  @moduledoc false
  use Oban.Worker, queue: :enqueue, max_attempts: 3

  alias Microwaveprop.Radio
  alias Microwaveprop.Weather
  alias Microwaveprop.Weather.HrrrClient
  alias Microwaveprop.Workers.HrrrFetchWorker
  alias Microwaveprop.Workers.IemreFetchWorker
  alias Microwaveprop.Workers.TerrainProfileWorker
  alias Microwaveprop.Workers.WeatherFetchWorker

  @asos_radius_km 150
  @sounding_radius_km 300
  # Oban jobs have ~149 params each; PG limit is 65535 params per query
  @insert_batch_size 400

  @impl Oban.Worker
  def perform(%Oban.Job{}) do
    enqueue_weather_jobs()
    enqueue_hrrr_jobs()
    enqueue_terrain_jobs()
    enqueue_iemre_jobs()

    :ok
  end

  defp enqueue_weather_jobs do
    case Radio.unprocessed_qsos() do
      [] ->
        :ok

      qsos ->
        Radio.backfill_distances(qsos)

        jobs = build_weather_jobs(qsos)

        if jobs != [] do
          insert_all_chunked(jobs)
        end

        qso_ids = Enum.map(qsos, & &1.id)
        Radio.mark_weather_queued!(qso_ids)

        enqueue_weather_jobs()
    end
  end

  defp enqueue_hrrr_jobs do
    case Radio.unprocessed_hrrr_qsos() do
      [] ->
        :ok

      qsos ->
        jobs = build_hrrr_jobs(qsos)

        if jobs != [] do
          insert_all_chunked(jobs)
        end

        qso_ids = Enum.map(qsos, & &1.id)
        Radio.mark_hrrr_queued!(qso_ids)

        enqueue_hrrr_jobs()
    end
  end

  defp enqueue_terrain_jobs do
    case Radio.unprocessed_terrain_qsos() do
      [] ->
        :ok

      qsos ->
        jobs = build_terrain_jobs(qsos)

        if jobs != [] do
          insert_all_chunked(jobs)
        end

        qso_ids = Enum.map(qsos, & &1.id)
        Radio.mark_terrain_queued!(qso_ids)

        # Continue until all QSOs are enqueued
        enqueue_terrain_jobs()
    end
  end

  def build_terrain_jobs(qsos) do
    qsos
    |> Enum.map(fn qso ->
      TerrainProfileWorker.new(%{"qso_id" => qso.id})
    end)
    |> Enum.uniq_by(fn changeset -> changeset.changes.args end)
  end

  def build_weather_jobs(qsos) do
    qsos
    |> Enum.flat_map(&jobs_for_qso/1)
    |> Enum.uniq_by(fn changeset -> changeset.changes.args end)
  end

  def build_hrrr_jobs(qsos) do
    # Group all QSO points by HRRR hour, then create one batch job per hour
    # instead of one job per point. This deduplicates GRIB2 downloads.
    qsos
    |> Enum.flat_map(&hrrr_points_for_qso/1)
    |> Enum.group_by(fn {_point, hour} -> hour end, fn {point, _hour} -> point end)
    |> Enum.map(fn {hour, points} ->
      unique_points =
        points
        |> Enum.uniq()
        |> Enum.map(fn {lat, lon} -> %{"lat" => lat, "lon" => lon} end)

      HrrrFetchWorker.new(%{
        "points" => unique_points,
        "valid_time" => DateTime.to_iso8601(hour)
      })
    end)
  end

  def build_iemre_jobs(qsos) do
    qsos
    |> Enum.flat_map(&iemre_job_for_qso/1)
    |> Enum.uniq_by(fn changeset -> changeset.changes.args end)
  end

  defp jobs_for_qso(qso) do
    qso
    |> Radio.qso_path_points()
    |> Enum.flat_map(fn {lat, lon} ->
      build_asos_jobs(lat, lon, qso.qso_timestamp) ++
        build_raob_jobs(lat, lon, qso.qso_timestamp)
    end)
  end

  defp enqueue_iemre_jobs do
    case Radio.unprocessed_iemre_qsos() do
      [] ->
        :ok

      qsos ->
        jobs = build_iemre_jobs(qsos)

        if jobs != [] do
          insert_all_chunked(jobs)
        end

        qso_ids = Enum.map(qsos, & &1.id)
        Radio.mark_iemre_queued!(qso_ids)

        enqueue_iemre_jobs()
    end
  end

  defp hrrr_points_for_qso(%{pos1: nil}), do: []

  defp hrrr_points_for_qso(qso) do
    rounded_time = HrrrClient.nearest_hrrr_hour(qso.qso_timestamp)

    qso
    |> Radio.qso_path_points()
    |> Enum.flat_map(fn {lat, lon} ->
      {rlat, rlon} = Weather.round_to_hrrr_grid(lat, lon)

      if Weather.has_hrrr_profile?(rlat, rlon, rounded_time) do
        []
      else
        [{{rlat, rlon}, rounded_time}]
      end
    end)
  end

  defp build_asos_jobs(lat, lon, timestamp) do
    start_dt = DateTime.add(timestamp, -2 * 3600, :second)
    end_dt = DateTime.add(timestamp, 2 * 3600, :second)

    lat
    |> Weather.nearby_stations(lon, "asos", @asos_radius_km)
    |> Enum.reject(fn station ->
      Weather.has_surface_observations?(station.id, start_dt, end_dt)
    end)
    |> Enum.map(fn station ->
      WeatherFetchWorker.new(%{
        "fetch_type" => "asos",
        "station_id" => station.id,
        "station_code" => station.station_code,
        "start_dt" => DateTime.to_iso8601(start_dt),
        "end_dt" => DateTime.to_iso8601(end_dt)
      })
    end)
  end

  defp iemre_job_for_qso(%{pos1: nil}), do: []

  defp iemre_job_for_qso(qso) do
    date = DateTime.to_date(qso.qso_timestamp)

    qso
    |> Radio.qso_path_points()
    |> Enum.flat_map(fn {lat, lon} ->
      {rlat, rlon} = Weather.round_to_iemre_grid(lat, lon)

      if Weather.has_iemre_observation?(rlat, rlon, date) do
        []
      else
        [
          IemreFetchWorker.new(%{
            "lat" => rlat,
            "lon" => rlon,
            "date" => Date.to_iso8601(date)
          })
        ]
      end
    end)
  end

  defp build_raob_jobs(lat, lon, timestamp) do
    sounding_times = Weather.sounding_times_around(timestamp)

    stations = Weather.nearby_stations(lat, lon, "sounding", @sounding_radius_km)

    for station <- stations,
        sounding_time <- sounding_times,
        not Weather.has_sounding?(station.id, sounding_time) do
      WeatherFetchWorker.new(%{
        "fetch_type" => "raob",
        "station_id" => station.id,
        "station_code" => station.station_code,
        "sounding_time" => DateTime.to_iso8601(sounding_time)
      })
    end
  end

  defp insert_all_chunked(jobs) do
    jobs
    |> Enum.chunk_every(@insert_batch_size)
    |> Enum.each(&Oban.insert_all/1)
  end
end