prop/test/microwaveprop/backtest/features_test.exs

defmodule Microwaveprop.Backtest.FeaturesTest do
  use Microwaveprop.DataCase, async: true

  alias Microwaveprop.Backtest.Features
  alias Microwaveprop.Weather
  alias Microwaveprop.Weather.HrrrNativeProfile

  @point_lat 32.9
  @point_lon -97.0
  @valid_time ~U[2026-03-28 18:00:00Z]

  defp create_profile(attrs) do
    base = %{
      valid_time: @valid_time,
      lat: @point_lat,
      lon: @point_lon
    }

    {:ok, _} = Weather.upsert_hrrr_profile(Map.merge(base, attrs))
  end

  describe "naive_gradient/3" do
    test "returns the nearest profile's min_refractivity_gradient" do
      create_profile(%{min_refractivity_gradient: -250.0})
      assert Features.naive_gradient(@point_lat, @point_lon, @valid_time) == -250.0
    end

    test "returns nil when no profile is within match window" do
      assert Features.naive_gradient(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "td_depression/3" do
    test "returns surface_temp_c minus surface_dewpoint_c" do
      create_profile(%{surface_temp_c: 20.0, surface_dewpoint_c: 14.0})
      assert Features.td_depression(@point_lat, @point_lon, @valid_time) == 6.0
    end

    test "returns nil when profile has no surface data" do
      create_profile(%{surface_temp_c: nil, surface_dewpoint_c: nil})
      assert Features.td_depression(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "time_of_day/3" do
    test "returns UTC hour + minute fraction and never calls the database" do
      assert Features.time_of_day(0.0, 0.0, ~U[2026-01-01 06:30:00Z]) == 6.5
      assert Features.time_of_day(0.0, 0.0, ~U[2026-01-01 00:00:00Z]) == 0.0
      assert Features.time_of_day(0.0, 0.0, ~U[2026-01-01 23:45:00Z]) == 23.75
    end
  end

  describe "pressure/3" do
    test "returns surface_pressure_mb from the nearest profile" do
      create_profile(%{surface_pressure_mb: 1013.2})
      assert Features.pressure(@point_lat, @point_lon, @valid_time) == 1013.2
    end

    test "returns nil when no profile exists" do
      assert Features.pressure(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "native_surface_refractivity/3" do
    test "computes N-units from native profile surface scalars" do
      insert_native_profile(%{
        surface_temp_k: 295.0,
        surface_spfh: 0.010,
        surface_pressure_pa: 101_325.0
      })

      result = Features.native_surface_refractivity(@point_lat, @point_lon, @valid_time)
      assert is_float(result)
      # Typical surface N is 250-400 in temperate latitudes
      assert result > 200.0 and result < 500.0
    end

    test "returns nil when no native profile exists" do
      assert Features.native_surface_refractivity(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "theta_e_jump/3" do
    test "returns the native profile's theta_e_jump_k" do
      insert_native_profile(%{theta_e_jump_k: 4.75})
      assert Features.theta_e_jump(@point_lat, @point_lon, @valid_time) == 4.75
    end

    test "returns nil when no native profile or no jump value" do
      assert Features.theta_e_jump(@point_lat, @point_lon, @valid_time) == nil
      insert_native_profile(%{theta_e_jump_k: nil})
      assert Features.theta_e_jump(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "shear_at_top/3" do
    test "returns the native profile's shear_at_top_ms" do
      insert_native_profile(%{shear_at_top_ms: 3.2})
      assert Features.shear_at_top(@point_lat, @point_lon, @valid_time) == 3.2
    end

    test "returns nil when the native profile lacks a shear value" do
      insert_native_profile(%{shear_at_top_ms: nil})
      assert Features.shear_at_top(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "duct_thickness/3" do
    test "returns the thickest duct's thickness_m" do
      insert_native_profile(%{
        ducts: [
          %{"thickness_m" => 120.0, "min_freq_ghz" => 18.0},
          %{"thickness_m" => 340.0, "min_freq_ghz" => 9.5},
          %{"thickness_m" => 210.0, "min_freq_ghz" => 12.0}
        ]
      })

      assert Features.duct_thickness(@point_lat, @point_lon, @valid_time) == 340.0
    end

    test "returns nil when there are no ducts" do
      insert_native_profile(%{ducts: []})
      assert Features.duct_thickness(@point_lat, @point_lon, @valid_time) == nil
    end

    test "returns nil when no native profile exists" do
      assert Features.duct_thickness(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "best_duct_freq/3" do
    test "returns the native profile's best_duct_band_ghz" do
      insert_native_profile(%{best_duct_band_ghz: 12.5})
      assert Features.best_duct_freq(@point_lat, @point_lon, @valid_time) == 12.5
    end

    test "returns nil when the native profile lacks best_duct_band_ghz" do
      insert_native_profile(%{best_duct_band_ghz: nil})
      assert Features.best_duct_freq(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "duct_usable_for_band/4" do
    test "returns 1.0 when the best duct traps the requested band" do
      insert_native_profile(%{best_duct_band_ghz: 10.0})
      assert Features.duct_usable_for_band(@point_lat, @point_lon, @valid_time, 24.0) == 1.0
      assert Features.duct_usable_for_band(@point_lat, @point_lon, @valid_time, 10.0) == 1.0
    end

    test "returns 0.0 when the best duct can't trap the requested band" do
      insert_native_profile(%{best_duct_band_ghz: 20.0})
      assert Features.duct_usable_for_band(@point_lat, @point_lon, @valid_time, 10.0) == 0.0
    end

    test "returns nil when there's no native profile" do
      assert Features.duct_usable_for_band(@point_lat, @point_lon, @valid_time, 10.0) == nil
    end
  end

  describe "distance_to_front/3 and parallel_to_front/3 placeholders" do
    test "both return nil and never touch the database" do
      assert Features.distance_to_front(@point_lat, @point_lon, @valid_time) == nil
      assert Features.parallel_to_front(@point_lat, @point_lon, @valid_time) == nil
    end
  end

  describe "all_features/0" do
    test "returns a name-keyed map of 3-arity feature closures" do
      features = Features.all_features()
      assert is_map(features)
      assert Map.has_key?(features, "naive_gradient")
      assert Map.has_key?(features, "td_depression")
      assert Map.has_key?(features, "time_of_day")
      assert Map.has_key?(features, "duct_thickness")

      # Excluded per the @doc contract
      refute Map.has_key?(features, "duct_usable_for_band")
      refute Map.has_key?(features, "distance_to_front")
      refute Map.has_key?(features, "bulk_richardson")

      # Every value is a 3-arity closure that returns a float or nil
      # without raising.
      for {_name, fun} <- features do
        assert is_function(fun, 3)
        result = fun.(@point_lat, @point_lon, @valid_time)
        assert is_nil(result) or is_float(result)
      end
    end
  end

  defp insert_native_profile(attrs) do
    base = %{
      valid_time: @valid_time,
      lat: @point_lat,
      lon: @point_lon,
      level_count: 1,
      heights_m: [10.0],
      temp_k: [295.0],
      spfh: [0.010],
      pressure_pa: [101_325.0],
      u_wind_ms: [2.0],
      v_wind_ms: [1.0],
      tke_m2s2: [0.5]
    }

    {:ok, _} =
      %HrrrNativeProfile{}
      |> HrrrNativeProfile.changeset(Map.merge(base, attrs))
      |> Repo.insert(on_conflict: :replace_all, conflict_target: [:valid_time, :lat, :lon])
  end
end