Filter active alerts in app service

internal/app/service.go

@@ -68,6 +68,26 @@ func (s *Service) LatestAlertRun(ctx context.Context) (*model.WeatherAlertRun, e
 	return s.repo.LatestAlertRun(ctx)
 }
 
+func (s *Service) LatestActiveAlertRun(ctx context.Context, activeAt time.Time) (*model.WeatherAlertRun, error) {
+	run, err := s.repo.LatestAlertRun(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if run == nil {
+		return nil, nil
+	}
+
+	out := cloneAlertRun(run)
+	alerts := out.Alerts[:0]
+	for _, alert := range out.Alerts {
+		if isActiveAlert(alert, activeAt) {
+			alerts = append(alerts, alert)
+		}
+	}
+	out.Alerts = alerts
+	return out, nil
+}
+
 func (s *Service) LatestConvectiveOutlook(ctx context.Context, filter OutlookFilter) (*model.WeatherOutlookRun, error) {
 	run, err := s.repo.LatestConvectiveOutlookRun(ctx)
 	if err != nil {
@@ -113,6 +133,53 @@ func normalizeOutlookType(value string) string {
 	return strings.ToLower(strings.TrimSpace(value))
 }
 
+func cloneAlertRun(run *model.WeatherAlertRun) *model.WeatherAlertRun {
+	out := *run
+	out.Latitude = copyFloat64(run.Latitude)
+	out.Longitude = copyFloat64(run.Longitude)
+	if run.Alerts != nil {
+		out.Alerts = make([]model.WeatherAlert, len(run.Alerts))
+		for i := range run.Alerts {
+			out.Alerts[i] = cloneAlert(run.Alerts[i])
+		}
+	}
+	return &out
+}
+
+func cloneAlert(alert model.WeatherAlert) model.WeatherAlert {
+	out := alert
+	out.Sent = copyTime(alert.Sent)
+	out.Effective = copyTime(alert.Effective)
+	out.Onset = copyTime(alert.Onset)
+	out.Expires = copyTime(alert.Expires)
+	if alert.References != nil {
+		out.References = make([]model.AlertReference, len(alert.References))
+		for i := range alert.References {
+			out.References[i] = cloneAlertReference(alert.References[i])
+		}
+	}
+	return out
+}
+
+func cloneAlertReference(ref model.AlertReference) model.AlertReference {
+	out := ref
+	out.Sent = copyTime(ref.Sent)
+	return out
+}
+
+func isActiveAlert(alert model.WeatherAlert, activeAt time.Time) bool {
+	if strings.EqualFold(strings.TrimSpace(alert.MessageType), "Cancel") {
+		return false
+	}
+	if alert.Effective != nil && activeAt.Before(*alert.Effective) {
+		return false
+	}
+	if alert.Expires != nil && !activeAt.Before(*alert.Expires) {
+		return false
+	}
+	return true
+}
+
 func cloneOutlookRun(run *model.WeatherOutlookRun) *model.WeatherOutlookRun {
 	out := *run
 	out.Latitude = copyFloat64(run.Latitude)