fix(stats): map protocol mileage fields

go/vehicle-gateway/internal/stats/daily_metric.go

@@ -99,7 +99,7 @@ func SamplesFromEnvelope(env envelope.FrameEnvelope, loc *time.Location) ([]Metr
 	if vin == "" {
 		return nil, nil
 	}
-	totalMileage, ok := floatField(env, envelope.FieldTotalMileageKM)
+	totalMileage, ok := totalMileageKMFromEnvelope(env)
 	if !ok {
 		return nil, nil
 	}
@@ -125,6 +125,41 @@ func SamplesFromEnvelope(env envelope.FrameEnvelope, loc *time.Location) ([]Metr
 	}}, nil
 }
 
+type mileageFieldMapping struct {
+	key   string
+	scale float64
+}
+
+func totalMileageKMFromEnvelope(env envelope.FrameEnvelope) (float64, bool) {
+	if value, ok := floatField(env, envelope.FieldTotalMileageKM); ok {
+		return value, true
+	}
+	for _, mapping := range mileageMappingsByProtocol(env.Protocol) {
+		value, ok := floatField(env, mapping.key)
+		if !ok {
+			continue
+		}
+		return value * mapping.scale, true
+	}
+	return 0, false
+}
+
+func mileageMappingsByProtocol(protocol envelope.Protocol) []mileageFieldMapping {
+	switch protocol {
+	case envelope.ProtocolGB32960:
+		return []mileageFieldMapping{{key: "gb32960.vehicle.total_mileage_km", scale: 1}}
+	case envelope.ProtocolJT808:
+		return []mileageFieldMapping{{key: "jt808.location.total_mileage_km", scale: 1}}
+	case envelope.ProtocolYutongMQTT:
+		return []mileageFieldMapping{
+			{key: "yutong_mqtt.data.total_mileage", scale: 0.001},
+			{key: "yutong_mqtt.root.data.total_mileage", scale: 0.001},
+		}
+	default:
+		return nil
+	}
+}
+
 const upsertDailyMileageSQL = `
 INSERT INTO vehicle_daily_mileage
   (vin, stat_date, protocol, daily_mileage_km,