fix(stats): map protocol mileage fields

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

@@ -30,7 +30,6 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 	if !ok {
 		return envelope.FrameEnvelope{}, false
 	}
-	statFields := fieldsWithCanonicalStats(fields, env.Fields)
 	out := envelope.FrameEnvelope{
 		EventID:          env.StableEventID() + ":fields",
 		TraceID:          env.TraceID,
@@ -45,7 +44,7 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 		SourceEndpoint:   env.SourceEndpoint,
 		EventTimeMS:      env.EventTimeMS,
 		ReceivedAtMS:     env.ReceivedAtMS,
-		Fields:           statFields,
+		Fields:           fields,
 		ParsedFields:     fields,
 		ParsedFieldTypes: fieldTypes,
 		Parsed: map[string]any{
@@ -57,22 +56,6 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 	return out, true
 }
 
-func fieldsWithCanonicalStats(mapped map[string]any, canonical map[string]any) map[string]any {
-	out := cloneAnyMap(mapped)
-	for _, key := range []string{
-		envelope.FieldTotalMileageKM,
-		envelope.FieldSpeedKMH,
-		envelope.FieldSOCPercent,
-		envelope.FieldLongitude,
-		envelope.FieldLatitude,
-	} {
-		if value, ok := canonical[key]; ok && value != nil {
-			out[key] = value
-		}
-	}
-	return out
-}
-
 func EnsureParsedFields(env *envelope.FrameEnvelope) bool {
 	if env == nil {
 		return false

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

@@ -39,7 +39,7 @@ func TestRealtimeKVFieldsFromGB32960ParsedDomains(t *testing.T) {
 	}
 }
 
-func TestBuildFieldsEnvelopeKeepsMappedAndCanonicalStatFields(t *testing.T) {
+func TestBuildFieldsEnvelopeUsesOnlyProtocolMappedFieldNames(t *testing.T) {
 	fieldsEnv, ok := BuildFieldsEnvelope(envelope.FrameEnvelope{
 		Protocol:     envelope.ProtocolGB32960,
 		VIN:          "VIN001",
@@ -65,9 +65,9 @@ func TestBuildFieldsEnvelopeKeepsMappedAndCanonicalStatFields(t *testing.T) {
 	if !ok {
 		t.Fatal("BuildFieldsEnvelope() should emit mapped fields")
 	}
-	for _, bareKey := range []string{"charge_status"} {
+	for _, bareKey := range []string{"charge_status", "soc_percent", "total_mileage_km"} {
 		if _, exists := fieldsEnv.Fields[bareKey]; exists {
-			t.Fatalf("fields envelope should not expose non-canonical bare env.Fields key %q: %#v", bareKey, fieldsEnv.Fields)
+			t.Fatalf("fields envelope should not expose non-protocol bare key %q: %#v", bareKey, fieldsEnv.Fields)
 		}
 	}
 	for _, mappedKey := range []string{
@@ -79,14 +79,6 @@ func TestBuildFieldsEnvelopeKeepsMappedAndCanonicalStatFields(t *testing.T) {
 			t.Fatalf("fields envelope missing mapped key %q: %#v", mappedKey, fieldsEnv.Fields)
 		}
 	}
-	for _, canonicalKey := range []string{envelope.FieldSOCPercent, envelope.FieldTotalMileageKM} {
-		if _, exists := fieldsEnv.Fields[canonicalKey]; !exists {
-			t.Fatalf("fields envelope should keep canonical stat key %q: %#v", canonicalKey, fieldsEnv.Fields)
-		}
-		if _, exists := fieldsEnv.ParsedFields[canonicalKey]; exists {
-			t.Fatalf("parsed fields should stay protocol-mapped without canonical duplicate %q: %#v", canonicalKey, fieldsEnv.ParsedFields)
-		}
-	}
 }
 
 func TestRealtimeKVFieldsFromJT808ParsedFields(t *testing.T) {

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,

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

@@ -40,6 +40,60 @@ func TestSamplesFromEnvelopeDerivesDailyMileageSample(t *testing.T) {
 	}
 }
 
+func TestSamplesFromEnvelopeMapsProtocolMileageFields(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	tests := []struct {
+		name     string
+		protocol envelope.Protocol
+		fields   map[string]any
+		wantKM   float64
+	}{
+		{
+			name:     "gb32960",
+			protocol: envelope.ProtocolGB32960,
+			fields:   map[string]any{"gb32960.vehicle.total_mileage_km": "38587"},
+			wantKM:   38587,
+		},
+		{
+			name:     "jt808",
+			protocol: envelope.ProtocolJT808,
+			fields:   map[string]any{"jt808.location.total_mileage_km": "12432.4"},
+			wantKM:   12432.4,
+		},
+		{
+			name:     "yutong mqtt meters",
+			protocol: envelope.ProtocolYutongMQTT,
+			fields:   map[string]any{"yutong_mqtt.data.total_mileage": "120756000"},
+			wantKM:   120756,
+		},
+		{
+			name:     "yutong mqtt root meters",
+			protocol: envelope.ProtocolYutongMQTT,
+			fields:   map[string]any{"yutong_mqtt.root.data.total_mileage": float64(22858000)},
+			wantKM:   22858,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			samples, err := SamplesFromEnvelope(envelope.FrameEnvelope{
+				Protocol:    tt.protocol,
+				VIN:         "LNBVIN00000000001",
+				EventTimeMS: time.Date(2026, 7, 1, 8, 30, 0, 0, loc).UnixMilli(),
+				Fields:      tt.fields,
+			}, loc)
+			if err != nil {
+				t.Fatalf("SamplesFromEnvelope() error = %v", err)
+			}
+			if len(samples) != 1 {
+				t.Fatalf("sample count = %d", len(samples))
+			}
+			if samples[0].TotalMileageKM != tt.wantKM {
+				t.Fatalf("total mileage = %v, want %v", samples[0].TotalMileageKM, tt.wantKM)
+			}
+		})
+	}
+}
+
 func TestSamplesFromEnvelopeSkipsMissingVIN(t *testing.T) {
 	loc := time.FixedZone("Asia/Shanghai", 8*3600)
 	samples, err := SamplesFromEnvelope(envelope.FrameEnvelope{