package core

import (
	"math"
	"testing"
	"time"

	"gitea.maximumdirect.net/ejr/weatherfeeder/model"
)

func TestObservationPayloadUS(t *testing.T) {
	obs := &model.WeatherObservation{
		StationID:               "KSTL",
		Timestamp:               time.Date(2026, 3, 20, 0, 0, 0, 0, time.UTC),
		ConditionCode:           2,
		TemperatureC:            float64Ptr(20),
		DewpointC:               float64Ptr(10),
		WindSpeedKmh:            float64Ptr(100),
		WindGustKmh:             float64Ptr(80),
		BarometricPressurePa:    float64Ptr(101325),
		VisibilityMeters:        float64Ptr(1609.344),
		ApparentTemperatureC:    float64Ptr(25),
		RelativeHumidityPercent: float64Ptr(50),
	}

	payload := ObservationPayload(obs, UnitsUS)
	converted, ok := payload.(WeatherObservationUS)
	if !ok {
		t.Fatalf("expected WeatherObservationUS payload, got %T", payload)
	}

	assertApprox(t, converted.TemperatureF, 68.0, 0.0001)
	assertApprox(t, converted.WindSpeedMph, 62.1371192237, 0.0001)
	assertApprox(t, converted.BarometricPressureInHg, 29.9212524019, 0.0001)
	assertApprox(t, converted.VisibilityMiles, 1.0, 0.0001)

	if converted.TemperatureF == nil || converted.DewpointF == nil || converted.ApparentTemperatureF == nil {
		t.Fatalf("expected converted Fahrenheit fields to be populated")
	}
}

func TestForecastPayloadUS(t *testing.T) {
	issuedAt := time.Date(2026, 3, 20, 12, 0, 0, 0, time.UTC)
	updatedAt := issuedAt.Add(1 * time.Hour)
	run := &model.WeatherForecastRun{
		LocationID:      "stl",
		IssuedAt:        issuedAt,
		UpdatedAt:       &updatedAt,
		Product:         model.ForecastProductHourly,
		ElevationMeters: float64Ptr(1000),
		Periods: []model.WeatherForecastPeriod{
			{
				StartTime:             issuedAt,
				EndTime:               issuedAt.Add(1 * time.Hour),
				ConditionCode:         63,
				TemperatureC:          float64Ptr(0),
				TemperatureCMin:       float64Ptr(-5),
				TemperatureCMax:       float64Ptr(5),
				WindSpeedKmh:          float64Ptr(64.37376),
				PrecipitationAmountMm: float64Ptr(25.4),
				SnowfallDepthMM:       float64Ptr(50.8),
			},
		},
	}

	payload := ForecastPayload(run, UnitsUS)
	converted, ok := payload.(WeatherForecastRunUS)
	if !ok {
		t.Fatalf("expected WeatherForecastRunUS payload, got %T", payload)
	}

	assertApprox(t, converted.ElevationFeet, 3280.839895, 0.0001)
	if len(converted.Periods) != 1 {
		t.Fatalf("expected 1 period, got %d", len(converted.Periods))
	}
	period := converted.Periods[0]
	assertApprox(t, period.TemperatureF, 32.0, 0.0001)
	assertApprox(t, period.TemperatureFMin, 23.0, 0.0001)
	assertApprox(t, period.TemperatureFMax, 41.0, 0.0001)
	assertApprox(t, period.WindSpeedMph, 40.0, 0.0001)
	assertApprox(t, period.PrecipitationAmountIn, 1.0, 0.0001)
	assertApprox(t, period.SnowfallDepthIn, 2.0, 0.0001)
}

func TestMetricPassthroughAndNilHandling(t *testing.T) {
	obs := &model.WeatherObservation{}
	metric := ObservationPayload(obs, UnitsMetric)
	metricObs, ok := metric.(*model.WeatherObservation)
	if !ok {
		t.Fatalf("expected metric payload to remain model type, got %T", metric)
	}
	if metricObs != obs {
		t.Fatalf("expected metric payload to be original pointer")
	}

	if ObservationPayload(nil, UnitsUS) != nil {
		t.Fatalf("expected nil observation input to return nil payload")
	}
	if ForecastPayload(nil, UnitsUS) != nil {
		t.Fatalf("expected nil forecast input to return nil payload")
	}
	if AlertsPayload(nil, UnitsUS) != nil {
		t.Fatalf("expected nil alerts input to return nil payload")
	}
}

func float64Ptr(v float64) *float64 {
	return &v
}

func assertApprox(t *testing.T, got *float64, want, eps float64) {
	t.Helper()
	if got == nil {
		t.Fatalf("expected value near %f, got nil", want)
	}
	if math.Abs(*got-want) > eps {
		t.Fatalf("expected %f +/- %f, got %f", want, eps, *got)
	}
}