Add US unit support for weather observations and forecasts

internal/adapters/inbound/httpapi/endpoints.go

@@ -3,11 +3,13 @@ package httpapi
 import (
 	"context"
 	"net/http"
+	"strings"
 
 	"gitea.maximumdirect.net/ejr/feedapi/bind"
 	"gitea.maximumdirect.net/ejr/feedapi/endpoint"
 	"gitea.maximumdirect.net/ejr/feedapi/render"
 	"gitea.maximumdirect.net/ejr/feedapi/response"
+	"gitea.maximumdirect.net/ejr/weatherapi/internal/core"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/model"
 )
 
@@ -18,45 +20,47 @@ type Service interface {
 	LatestActiveAlerts(ctx context.Context) (*model.WeatherAlertRun, error)
 }
 
-type emptyRequest struct{}
+type queryRequest struct {
+	Units core.Units
+}
 
 func Definitions(svc Service) []endpoint.Definition {
 	return []endpoint.Definition{
 		endpoint.GET(
 			"/observations",
-			bindFormatOnly,
-			func(ctx context.Context, _ emptyRequest) (any, error) {
+			bindQuery,
+			func(ctx context.Context, req queryRequest) (any, error) {
 				obs, err := svc.LatestObservation(ctx)
 				if err != nil {
 					return nil, err
 				}
-				return response.Envelope{Data: obs}, nil
+				return response.Envelope{Data: core.ObservationPayload(obs, req.Units)}, nil
 			},
 			endpoint.WithProduces(render.FormatJSON, render.FormatXML, render.FormatText),
 			endpoint.WithTemplate("observations.txt.tmpl"),
 		),
 		endpoint.GET(
 			"/forecast/hourly",
-			bindFormatOnly,
-			func(ctx context.Context, _ emptyRequest) (any, error) {
+			bindQuery,
+			func(ctx context.Context, req queryRequest) (any, error) {
 				run, err := svc.LatestHourlyForecast(ctx)
 				if err != nil {
 					return nil, err
 				}
-				return response.Envelope{Data: run}, nil
+				return response.Envelope{Data: core.ForecastPayload(run, req.Units)}, nil
 			},
 			endpoint.WithProduces(render.FormatJSON, render.FormatXML, render.FormatText),
 			endpoint.WithTemplate("forecast_hourly.txt.tmpl"),
 		),
 		endpoint.GET(
 			"/alerts/active",
-			bindFormatOnly,
-			func(ctx context.Context, _ emptyRequest) (any, error) {
+			bindQuery,
+			func(ctx context.Context, req queryRequest) (any, error) {
 				run, err := svc.LatestActiveAlerts(ctx)
 				if err != nil {
 					return nil, err
 				}
-				return response.Envelope{Data: run}, nil
+				return response.Envelope{Data: core.AlertsPayload(run, req.Units)}, nil
 			},
 			endpoint.WithProduces(render.FormatJSON, render.FormatXML, render.FormatText),
 			endpoint.WithTemplate("alerts_active.txt.tmpl"),
@@ -64,13 +68,38 @@ func Definitions(svc Service) []endpoint.Definition {
 	}
 }
 
-func bindFormatOnly(r *http.Request) (emptyRequest, error) {
-	_, err := bind.CommonQueryParams(r, bind.QueryPolicy{
+func bindQuery(r *http.Request) (queryRequest, error) {
+	normalizeCommonQueryValue(r, "units")
+	normalizeCommonQueryValue(r, "format")
+
+	common, err := bind.CommonQueryParams(r, bind.QueryPolicy{
+		AllowUnits:    true,
 		AllowFormat:   true,
+		DefaultUnits:  string(core.UnitsMetric),
 		RejectUnknown: true,
 	})
 	if err != nil {
-		return emptyRequest{}, err
+		return queryRequest{}, err
 	}
-	return emptyRequest{}, nil
+
+	units := core.Units(strings.ToLower(strings.TrimSpace(common.Units)))
+	if units == "" {
+		units = core.UnitsMetric
+	}
+	return queryRequest{Units: units}, nil
+}
+
+func normalizeCommonQueryValue(r *http.Request, key string) {
+	q := r.URL.Query()
+	values, ok := q[key]
+	if !ok || len(values) == 0 {
+		return
+	}
+
+	normalized := strings.ToLower(strings.TrimSpace(values[0]))
+	if normalized == values[0] {
+		return
+	}
+	q.Set(key, normalized)
+	r.URL.RawQuery = q.Encode()
 }