fix: keep valid realtime mileage

go/vehicle-gateway/internal/realtime/repository.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -155,6 +156,9 @@ func mergeFields(snapshot *Snapshot, fields map[string]any, eventMS int64) {
 		snapshot.FieldTimesMS = map[string]int64{}
 	}
 	for key, value := range fields {
+		if key == envelope.FieldTotalMileageKM && !positiveNumber(value) {
+			continue
+		}
 		if eventMS >= snapshot.FieldTimesMS[key] {
 			snapshot.Fields[key] = value
 			snapshot.FieldTimesMS[key] = eventMS
@@ -162,6 +166,28 @@ func mergeFields(snapshot *Snapshot, fields map[string]any, eventMS int64) {
 	}
 }
 
+func positiveNumber(value any) bool {
+	switch typed := value.(type) {
+	case float64:
+		return typed > 0
+	case float32:
+		return typed > 0
+	case int:
+		return typed > 0
+	case int64:
+		return typed > 0
+	case uint16:
+		return typed > 0
+	case uint32:
+		return typed > 0
+	case string:
+		parsed, err := strconv.ParseFloat(strings.TrimSpace(typed), 64)
+		return err == nil && parsed > 0
+	default:
+		return false
+	}
+}
+
 func cloneFields(fields map[string]any) map[string]any {
 	if len(fields) == 0 {
 		return map[string]any{}