Feature addition to support narrative forecast updates from the NWS

internal/normalizers/nws/forecast.go

@@ -16,10 +16,11 @@ import (
 
 // ForecastNormalizer converts:
 //
-//	standards.SchemaRawNWSHourlyForecastV1 -> standards.SchemaWeatherForecastV1
+//	standards.SchemaRawNWSHourlyForecastV1    -> standards.SchemaWeatherForecastV1
+//	standards.SchemaRawNWSNarrativeForecastV1 -> standards.SchemaWeatherForecastV1
 //
 // It keeps one NWS forecast normalization entrypoint and dispatches to product-specific
-// builders by raw schema. Today only hourly is implemented.
+// builders by raw schema.
 //
 // Caveats / policy:
 //  1. NWS forecast periods do not include METAR presentWeather phenomena, so ConditionCode
@@ -32,6 +33,8 @@ func (ForecastNormalizer) Match(e event.Event) bool {
 	switch strings.TrimSpace(e.Schema) {
 	case standards.SchemaRawNWSHourlyForecastV1:
 		return true
+	case standards.SchemaRawNWSNarrativeForecastV1:
+		return true
 	default:
 		return false
 	}
@@ -47,6 +50,8 @@ func normalizeForecastEventBySchema(in event.Event) (*event.Event, error) {
 	switch strings.TrimSpace(in.Schema) {
 	case standards.SchemaRawNWSHourlyForecastV1:
 		return normalizeHourlyForecastEvent(in)
+	case standards.SchemaRawNWSNarrativeForecastV1:
+		return normalizeNarrativeForecastEvent(in)
 	default:
 		return nil, fmt.Errorf("unsupported nws forecast schema %q", strings.TrimSpace(in.Schema))
 	}
@@ -61,6 +66,15 @@ func normalizeHourlyForecastEvent(in event.Event) (*event.Event, error) {
 	)
 }
 
+func normalizeNarrativeForecastEvent(in event.Event) (*event.Event, error) {
+	return normcommon.NormalizeJSON(
+		in,
+		"nws narrative forecast",
+		standards.SchemaWeatherForecastV1,
+		buildNarrativeForecast,
+	)
+}
+
 // buildHourlyForecast contains hourly forecast mapping logic (provider -> canonical model).
 func buildHourlyForecast(parsed nwsHourlyForecastResponse) (model.WeatherForecastRun, time.Time, error) {
 	issuedAt, updatedAt, err := parseForecastRunTimes(parsed.Properties.GeneratedAt, parsed.Properties.UpdateTime)
@@ -95,6 +109,40 @@ func buildHourlyForecast(parsed nwsHourlyForecastResponse) (model.WeatherForecas
 	return run, issuedAt, nil
 }
 
+// buildNarrativeForecast contains narrative forecast mapping logic (provider -> canonical model).
+func buildNarrativeForecast(parsed nwsNarrativeForecastResponse) (model.WeatherForecastRun, time.Time, error) {
+	issuedAt, updatedAt, err := parseForecastRunTimes(parsed.Properties.GeneratedAt, parsed.Properties.UpdateTime)
+	if err != nil {
+		return model.WeatherForecastRun{}, time.Time{}, err
+	}
+
+	// Best-effort location centroid from the GeoJSON polygon (optional).
+	lat, lon := centroidLatLon(parsed.Geometry.Coordinates)
+
+	run := newForecastRunBase(
+		issuedAt,
+		updatedAt,
+		model.ForecastProductNarrative,
+		lat,
+		lon,
+		parsed.Properties.Elevation.Value,
+	)
+
+	periods := make([]model.WeatherForecastPeriod, 0, len(parsed.Properties.Periods))
+	for i, p := range parsed.Properties.Periods {
+		period, err := mapNarrativeForecastPeriod(i, p)
+		if err != nil {
+			return model.WeatherForecastRun{}, time.Time{}, err
+		}
+		periods = append(periods, period)
+	}
+
+	run.Periods = periods
+
+	// EffectiveAt policy for forecasts: treat IssuedAt as the effective time (dedupe-friendly).
+	return run, issuedAt, nil
+}
+
 func parseForecastRunTimes(generatedAt, updateTime string) (time.Time, *time.Time, error) {
 	issuedStr := strings.TrimSpace(generatedAt)
 	if issuedStr == "" {
@@ -199,3 +247,47 @@ func mapHourlyForecastPeriod(idx int, p nwsHourlyForecastPeriod) (model.WeatherF
 		ProbabilityOfPrecipitationPercent: p.ProbabilityOfPrecipitation.Value,
 	}, nil
 }
+
+func mapNarrativeForecastPeriod(idx int, p nwsNarrativeForecastPeriod) (model.WeatherForecastPeriod, error) {
+	start, end, err := parseForecastPeriodWindow(p.StartTime, p.EndTime, idx)
+	if err != nil {
+		return model.WeatherForecastPeriod{}, err
+	}
+
+	// NWS narrative supplies isDaytime; make it a pointer to match the canonical model.
+	var isDay *bool
+	if p.IsDaytime != nil {
+		b := *p.IsDaytime
+		isDay = &b
+	}
+
+	tempC := tempCFromNWS(p.Temperature, p.TemperatureUnit)
+
+	// Infer WMO from shortForecast (and fall back to icon token).
+	shortForecast := strings.TrimSpace(p.ShortForecast)
+	wmo := wmoFromNWSForecast(shortForecast, p.Icon, tempC)
+
+	textDescription := strings.TrimSpace(p.DetailedForecast)
+	if textDescription == "" {
+		textDescription = shortForecast
+	}
+
+	return model.WeatherForecastPeriod{
+		StartTime: start,
+		EndTime:   end,
+
+		Name:  strings.TrimSpace(p.Name),
+		IsDay: isDay,
+
+		ConditionCode: wmo,
+
+		TextDescription: textDescription,
+
+		TemperatureC: tempC,
+
+		WindDirectionDegrees: parseNWSWindDirectionDegrees(p.WindDirection),
+		WindSpeedKmh:         parseNWSWindSpeedKmh(p.WindSpeed),
+
+		ProbabilityOfPrecipitationPercent: p.ProbabilityOfPrecipitation.Value,
+	}, nil
+}