defmodule Microwaveprop.Weather do
  @moduledoc false

  import Ecto.Query

  alias Microwaveprop.Repo
  alias Microwaveprop.Weather.HrrrProfile
  alias Microwaveprop.Weather.IemClient
  alias Microwaveprop.Weather.IemreObservation
  alias Microwaveprop.Weather.SolarIndex
  alias Microwaveprop.Weather.Sounding
  alias Microwaveprop.Weather.Station
  alias Microwaveprop.Weather.SurfaceObservation
  alias Microwaveprop.Weather.WeatherLayers

  require Logger

  # Approximate km per degree latitude
  @km_per_deg_lat 111.0

  def find_or_create_station(attrs) do
    code = attrs[:station_code] || attrs["station_code"]
    type = attrs[:station_type] || attrs["station_type"]

    if code && type do
      case Repo.get_by(Station, station_code: code, station_type: type) do
        nil ->
          %Station{}
          |> Station.changeset(attrs)
          |> Repo.insert()

        station ->
          {:ok, station}
      end
    else
      %Station{}
      |> Station.changeset(attrs)
      |> Repo.insert()
    end
  end

  def upsert_surface_observation(%Station{} = station, attrs) do
    attrs = Map.put(attrs, :station_id, station.id)

    %SurfaceObservation{}
    |> SurfaceObservation.changeset(attrs)
    |> Repo.insert(
      on_conflict:
        from(s in SurfaceObservation,
          update: [
            set: [
              temp_f: fragment("EXCLUDED.temp_f"),
              dewpoint_f: fragment("EXCLUDED.dewpoint_f"),
              relative_humidity: fragment("EXCLUDED.relative_humidity"),
              wind_speed_kts: fragment("EXCLUDED.wind_speed_kts"),
              sea_level_pressure_mb: fragment("EXCLUDED.sea_level_pressure_mb"),
              sky_condition: fragment("EXCLUDED.sky_condition"),
              precip_1h_in: fragment("EXCLUDED.precip_1h_in"),
              wx_codes: fragment("EXCLUDED.wx_codes"),
              updated_at: fragment("EXCLUDED.updated_at")
            ]
          ],
          where:
            s.temp_f != fragment("EXCLUDED.temp_f") or
              s.dewpoint_f != fragment("EXCLUDED.dewpoint_f") or
              s.relative_humidity != fragment("EXCLUDED.relative_humidity") or
              s.wind_speed_kts != fragment("EXCLUDED.wind_speed_kts") or
              s.sea_level_pressure_mb != fragment("EXCLUDED.sea_level_pressure_mb")
        ),
      conflict_target: [:station_id, :observed_at],
      returning: true,
      stale_error_field: :id
    )
  end

  def upsert_sounding(%Station{} = station, attrs) do
    attrs = Map.put(attrs, :station_id, station.id)

    %Sounding{}
    |> Sounding.changeset(attrs)
    |> Repo.insert(
      on_conflict:
        from(s in Sounding,
          update: [
            set: [
              profile: fragment("EXCLUDED.profile"),
              level_count: fragment("EXCLUDED.level_count"),
              surface_pressure_mb: fragment("EXCLUDED.surface_pressure_mb"),
              surface_temp_c: fragment("EXCLUDED.surface_temp_c"),
              surface_dewpoint_c: fragment("EXCLUDED.surface_dewpoint_c"),
              surface_refractivity: fragment("EXCLUDED.surface_refractivity"),
              min_refractivity_gradient: fragment("EXCLUDED.min_refractivity_gradient"),
              boundary_layer_depth_m: fragment("EXCLUDED.boundary_layer_depth_m"),
              precipitable_water_mm: fragment("EXCLUDED.precipitable_water_mm"),
              k_index: fragment("EXCLUDED.k_index"),
              lifted_index: fragment("EXCLUDED.lifted_index"),
              ducting_detected: fragment("EXCLUDED.ducting_detected"),
              duct_characteristics: fragment("EXCLUDED.duct_characteristics"),
              updated_at: fragment("EXCLUDED.updated_at")
            ]
          ],
          where:
            s.level_count != fragment("EXCLUDED.level_count") or
              s.surface_temp_c != fragment("EXCLUDED.surface_temp_c") or
              s.surface_refractivity != fragment("EXCLUDED.surface_refractivity")
        ),
      conflict_target: [:station_id, :observed_at],
      returning: true,
      stale_error_field: :id
    )
  end

  def upsert_solar_index(attrs) do
    %SolarIndex{}
    |> SolarIndex.changeset(attrs)
    |> Repo.insert(
      on_conflict:
        from(s in SolarIndex,
          update: [
            set: [
              sfi: fragment("EXCLUDED.sfi"),
              sfi_adjusted: fragment("EXCLUDED.sfi_adjusted"),
              sunspot_number: fragment("EXCLUDED.sunspot_number"),
              ap_index: fragment("EXCLUDED.ap_index"),
              kp_values: fragment("EXCLUDED.kp_values"),
              updated_at: fragment("EXCLUDED.updated_at")
            ]
          ],
          where:
            s.sfi != fragment("EXCLUDED.sfi") or
              s.ap_index != fragment("EXCLUDED.ap_index")
        ),
      conflict_target: [:date],
      returning: true,
      stale_error_field: :id
    )
  end

  def has_surface_observations?(station_id, start_dt, end_dt) do
    SurfaceObservation
    |> where([o], o.station_id == ^station_id)
    |> where([o], o.observed_at >= ^start_dt and o.observed_at <= ^end_dt)
    |> Repo.exists?()
  end

  @doc "Returns a MapSet of station_ids that have surface observations in the time window."
  def station_ids_with_surface_observations(station_ids, start_dt, end_dt) do
    SurfaceObservation
    |> where([o], o.station_id in ^station_ids)
    |> where([o], o.observed_at >= ^start_dt and o.observed_at <= ^end_dt)
    |> select([o], o.station_id)
    |> distinct(true)
    |> Repo.all()
    |> MapSet.new()
  end

  def has_sounding?(station_id, observed_at) do
    Sounding
    |> where([s], s.station_id == ^station_id and s.observed_at == ^observed_at)
    |> Repo.exists?()
  end

  @doc "Returns a MapSet of {station_id, observed_at} tuples that have soundings."
  def station_ids_with_soundings(station_ids, sounding_times) do
    Sounding
    |> where([s], s.station_id in ^station_ids and s.observed_at in ^sounding_times)
    |> select([s], {s.station_id, s.observed_at})
    |> distinct(true)
    |> Repo.all()
    |> MapSet.new()
  end

  @doc "Batch upsert solar indices using insert_all in chunks of 500."
  def upsert_solar_indices_batch(records) do
    now = DateTime.truncate(DateTime.utc_now(), :second)

    records
    |> Enum.chunk_every(500)
    |> Enum.reduce(0, fn chunk, acc ->
      entries =
        Enum.map(chunk, fn attrs ->
          %{
            id: Ecto.UUID.generate(),
            date: attrs[:date] || attrs.date,
            sfi: attrs[:sfi],
            sfi_adjusted: attrs[:sfi_adjusted],
            sunspot_number: attrs[:sunspot_number],
            ap_index: attrs[:ap_index],
            kp_values: attrs[:kp_values],
            inserted_at: now,
            updated_at: now
          }
        end)

      {count, _} =
        Repo.insert_all(SolarIndex, entries,
          on_conflict:
            from(s in SolarIndex,
              update: [
                set: [
                  sfi: fragment("EXCLUDED.sfi"),
                  sfi_adjusted: fragment("EXCLUDED.sfi_adjusted"),
                  sunspot_number: fragment("EXCLUDED.sunspot_number"),
                  ap_index: fragment("EXCLUDED.ap_index"),
                  kp_values: fragment("EXCLUDED.kp_values"),
                  updated_at: fragment("EXCLUDED.updated_at")
                ]
              ],
              where:
                s.sfi != fragment("EXCLUDED.sfi") or
                  s.ap_index != fragment("EXCLUDED.ap_index")
            ),
          conflict_target: [:date]
        )

      acc + count
    end)
  end

  def get_solar_index(date) do
    Repo.get_by(SolarIndex, date: date)
  end

  def existing_solar_dates do
    SolarIndex
    |> select([s], s.date)
    |> Repo.all()
    |> MapSet.new()
  end

  def sync_stations! do
    asos =
      for s <-
            ~w(AK AL AR AZ CA CO CT DE FL GA HI IA ID IL IN KS KY LA MA MD ME MI MN MO MS MT NC ND NE NH NJ NM NV NY OH OK OR PA RI SC SD TN TX UT VA VT WA WI WV WY),
          do: "#{s}_ASOS"

    for network <- asos ++ ["RAOB"] do
      type = if String.contains?(network, "ASOS"), do: "asos", else: "sounding"

      case IemClient.fetch_network(network) do
        {:ok, stations} ->
          for s <- stations do
            %Station{}
            |> Station.changeset(Map.put(s, :station_type, type))
            |> Repo.insert(on_conflict: :nothing, conflict_target: [:station_code, :station_type])
          end

          Logger.info("Synced #{length(stations)} stations from #{network}")

        {:error, e} ->
          Logger.warning("Failed to sync #{network}: #{inspect(e)}")
      end

      Process.sleep(200)
    end

    count = Repo.aggregate(Station, :count)
    Logger.info("Weather stations sync complete: #{count} total")
    :ok
  end

  def nearby_stations(lat, lon, station_type, radius_km) do
    dlat = radius_km / @km_per_deg_lat
    dlon = radius_km / (@km_per_deg_lat * :math.cos(lat * :math.pi() / 180))

    Station
    |> where([s], s.station_type == ^station_type)
    |> where(
      [s],
      s.lat >= ^(lat - dlat) and s.lat <= ^(lat + dlat) and
        s.lon >= ^(lon - dlon) and s.lon <= ^(lon + dlon)
    )
    |> Repo.all()
  end

  def sounding_times_around(dt) do
    date = DateTime.to_date(dt)

    times =
      if dt.hour < 12 do
        [
          DateTime.new!(Date.add(date, -1), ~T[12:00:00], "Etc/UTC"),
          DateTime.new!(date, ~T[00:00:00], "Etc/UTC")
        ]
      else
        [
          DateTime.new!(date, ~T[00:00:00], "Etc/UTC"),
          DateTime.new!(date, ~T[12:00:00], "Etc/UTC")
        ]
      end

    Enum.uniq(times)
  end

  def weather_for_contact(contact_params, opts \\ []) do
    lat = contact_params[:lat] || contact_params.lat
    lon = contact_params[:lon] || contact_params.lon
    timestamp = contact_params[:timestamp] || contact_params.timestamp

    radius_km = Keyword.get(opts, :radius_km, 150)
    time_window_hours = Keyword.get(opts, :time_window_hours, 6)

    # Bounding box in degrees
    dlat = radius_km / @km_per_deg_lat
    dlon = radius_km / (@km_per_deg_lat * :math.cos(lat * :math.pi() / 180))

    time_start = DateTime.add(timestamp, -time_window_hours * 3600, :second)
    time_end = DateTime.add(timestamp, time_window_hours * 3600, :second)

    station_ids =
      Station
      |> where(
        [s],
        s.lat >= ^(lat - dlat) and s.lat <= ^(lat + dlat) and
          s.lon >= ^(lon - dlon) and s.lon <= ^(lon + dlon)
      )
      |> select([s], s.id)

    surface_observations =
      SurfaceObservation
      |> where([o], o.station_id in subquery(station_ids))
      |> where([o], o.observed_at >= ^time_start and o.observed_at <= ^time_end)
      |> preload(:station)
      |> Repo.all()

    soundings =
      Sounding
      |> where([s], s.station_id in subquery(station_ids))
      |> where([s], s.observed_at >= ^time_start and s.observed_at <= ^time_end)
      |> preload(:station)
      |> Repo.all()

    %{surface_observations: surface_observations, soundings: soundings}
  end

  def latest_grid_valid_time do
    Repo.one(
      from(h in HrrrProfile,
        where: h.is_grid_point == true,
        select: max(h.valid_time)
      )
    )
  end

  def latest_weather_grid(bounds) do
    case latest_grid_valid_time() do
      nil ->
        []

      latest_vt ->
        from(h in HrrrProfile,
          where:
            h.valid_time == ^latest_vt and
              h.is_grid_point == true and
              h.lat >= ^bounds["south"] and h.lat <= ^bounds["north"] and
              h.lon >= ^bounds["west"] and h.lon <= ^bounds["east"],
          select: %{
            lat: h.lat,
            lon: h.lon,
            valid_time: h.valid_time,
            temperature: h.surface_temp_c,
            dewpoint_depression: fragment("? - ?", h.surface_temp_c, h.surface_dewpoint_c),
            bl_height: h.hpbl_m,
            pwat: h.pwat_mm,
            refractivity_gradient: h.min_refractivity_gradient,
            ducting: h.ducting_detected,
            surface_pressure_mb: h.surface_pressure_mb,
            surface_temp_c: h.surface_temp_c,
            surface_dewpoint_c: h.surface_dewpoint_c,
            surface_refractivity: h.surface_refractivity,
            profile: h.profile,
            duct_characteristics: h.duct_characteristics
          }
        )
        |> Repo.all()
        |> Enum.map(&derive_and_clean/1)
    end
  end

  def weather_point_detail(lat, lon, valid_time) do
    step = 0.125
    snapped_lat = Float.round(Float.round(lat / step) * step, 3)
    snapped_lon = Float.round(Float.round(lon / step) * step, 3)

    from(h in HrrrProfile,
      where: h.lat == ^snapped_lat and h.lon == ^snapped_lon and h.valid_time == ^valid_time,
      select: %{
        lat: h.lat,
        lon: h.lon,
        valid_time: h.valid_time,
        temperature: h.surface_temp_c,
        dewpoint_depression: fragment("? - ?", h.surface_temp_c, h.surface_dewpoint_c),
        bl_height: h.hpbl_m,
        pwat: h.pwat_mm,
        refractivity_gradient: h.min_refractivity_gradient,
        ducting: h.ducting_detected,
        surface_pressure_mb: h.surface_pressure_mb,
        surface_temp_c: h.surface_temp_c,
        surface_dewpoint_c: h.surface_dewpoint_c,
        surface_refractivity: h.surface_refractivity,
        profile: h.profile,
        duct_characteristics: h.duct_characteristics
      }
    )
    |> Repo.one()
    |> then(fn
      nil -> nil
      row -> derive_and_clean(row)
    end)
  end

  defp derive_and_clean(row) do
    derived = WeatherLayers.derive(row)

    row
    |> Map.merge(derived)
    |> Map.drop([:profile, :duct_characteristics, :surface_temp_c, :surface_dewpoint_c])
  end

  def upsert_hrrr_profile(attrs) do
    %HrrrProfile{}
    |> HrrrProfile.changeset(attrs)
    |> Repo.insert(
      on_conflict: :nothing,
      conflict_target: [:lat, :lon, :valid_time]
    )
  end

  def upsert_hrrr_profiles_batch(profiles, _opts \\ []) do
    now = DateTime.truncate(DateTime.utc_now(), :second)

    profiles
    |> Enum.chunk_every(500)
    |> Enum.reduce({0, nil}, fn chunk, {total_count, _} ->
      entries =
        Enum.map(chunk, fn attrs ->
          is_gp =
            rem(round(attrs.lat * 1000), 125) == 0 and
              rem(round(attrs.lon * 1000), 125) == 0

          Map.merge(attrs, %{
            id: Ecto.UUID.generate(),
            is_grid_point: is_gp,
            inserted_at: now,
            updated_at: now
          })
        end)

      {count, rows} =
        Repo.insert_all(HrrrProfile, entries,
          on_conflict: :nothing,
          conflict_target: [:lat, :lon, :valid_time]
        )

      {total_count + count, rows}
    end)
  end

  def has_hrrr_profile?(lat, lon, valid_time) do
    dlat = 0.07
    dlon = 0.07

    HrrrProfile
    |> where(
      [h],
      h.lat >= ^(lat - dlat) and h.lat <= ^(lat + dlat) and
        h.lon >= ^(lon - dlon) and h.lon <= ^(lon + dlon) and
        h.valid_time == ^valid_time
    )
    |> Repo.exists?()
  end

  def hrrr_for_contact(%{pos1: nil}), do: nil

  def hrrr_for_contact(contact) do
    lat = contact.pos1["lat"]
    lon = contact.pos1["lon"] || contact.pos1["lng"]

    if lat && lon do
      find_nearest_hrrr(lat, lon, contact.qso_timestamp)
    end
  end

  def find_nearest_hrrr(lat, lon, timestamp) do
    dlat = 0.07
    dlon = 0.07
    time_start = DateTime.add(timestamp, -3600, :second)
    time_end = DateTime.add(timestamp, 3600, :second)

    HrrrProfile
    |> where(
      [h],
      h.lat >= ^(lat - dlat) and h.lat <= ^(lat + dlat) and
        h.lon >= ^(lon - dlon) and h.lon <= ^(lon + dlon) and
        h.valid_time >= ^time_start and h.valid_time <= ^time_end
    )
    |> order_by([h],
      asc:
        fragment(
          "ABS(? - ?) + ABS(? - ?) + ABS(EXTRACT(EPOCH FROM ? - ?))",
          h.lat,
          ^lat,
          h.lon,
          ^lon,
          h.valid_time,
          ^timestamp
        )
    )
    |> limit(1)
    |> Repo.one()
  end

  def hrrr_profiles_for_path(%{pos1: nil}), do: []

  def hrrr_profiles_for_path(contact) do
    contact
    |> Microwaveprop.Radio.contact_path_points()
    |> Enum.map(fn {lat, lon} -> find_nearest_hrrr(lat, lon, contact.qso_timestamp) end)
    |> Enum.reject(&is_nil/1)
  end

  def round_to_hrrr_grid(lat, lon) do
    {Float.round(lat / 1.0, 2), Float.round(lon / 1.0, 2)}
  end

  @doc """
  Delete HRRR grid profiles older than 24 hours that sit on the 0.125° grid.
  Preserves QSO-linked profiles which are at arbitrary lat/lon positions.
  With 19 forecast hours per run, this keeps ~2 runs worth of grid profiles.
  """
  def prune_old_grid_profiles do
    cutoff = DateTime.add(DateTime.utc_now(), -24, :hour)
    # Bound the scan to recent partitions only (grid profiles are at most ~48h old).
    # Without a lower bound, Postgres scans every partition back to 2016.
    floor = DateTime.add(DateTime.utc_now(), -72, :hour)

    # Only delete profiles on the 0.125° propagation grid, preserving QSO-linked
    # profiles which sit at arbitrary lat/lon positions (HRRR's native ~3km grid).
    %{num_rows: deleted} =
      Repo.query!(
        """
        DELETE FROM hrrr_profiles
        WHERE valid_time >= $2 AND valid_time < $1
          AND is_grid_point = true
        """,
        [cutoff, floor],
        timeout: 300_000
      )

    if deleted > 0 do
      require Logger

      Logger.info("Pruned #{deleted} old HRRR grid profiles (valid_time < #{cutoff})")
    end

    deleted
  end

  def round_to_iemre_grid(lat, lon) do
    {Float.round(lat * 8) / 8, Float.round(lon * 8) / 8}
  end

  def upsert_iemre_observation(attrs) do
    %IemreObservation{}
    |> IemreObservation.changeset(attrs)
    |> Repo.insert(
      on_conflict: :nothing,
      conflict_target: [:lat, :lon, :date]
    )
  end

  def has_iemre_observation?(lat, lon, date) do
    IemreObservation
    |> where([i], i.lat == ^lat and i.lon == ^lon and i.date == ^date)
    |> Repo.exists?()
  end

  def iemre_for_contact(%{pos1: nil}), do: nil

  def iemre_for_contact(contact) do
    lat = contact.pos1["lat"]
    lon = contact.pos1["lon"] || contact.pos1["lng"]

    if lat && lon do
      find_nearest_iemre(lat, lon, contact.qso_timestamp)
    end
  end

  def find_nearest_iemre(lat, lon, timestamp) do
    {rlat, rlon} = round_to_iemre_grid(lat, lon)
    date = DateTime.to_date(timestamp)

    IemreObservation
    |> where([i], i.lat == ^rlat and i.lon == ^rlon and i.date == ^date)
    |> Repo.one()
  end

  def iemre_for_path(%{pos1: nil}), do: []

  def iemre_for_path(contact) do
    contact
    |> Microwaveprop.Radio.contact_path_points()
    |> Enum.map(fn {lat, lon} -> find_nearest_iemre(lat, lon, contact.qso_timestamp) end)
    |> Enum.reject(&is_nil/1)
  end
end