feat: build vehicle data platform and production pipeline

go/vehicle-gateway/internal/telemetry/mileage.go

@@ -0,0 +1,89 @@
+package telemetry
+
+import (
+	"encoding/json"
+	"strconv"
+	"strings"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+type MileageFieldMapping struct {
+	Key   string
+	Scale float64
+}
+
+// MileageFieldMappings is the single protocol-to-unit contract used by every
+// projection that exposes or calculates total mileage.
+func MileageFieldMappings(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_km", Scale: 1},
+			{Key: "yutong_mqtt.root.data.total_mileage_km", Scale: 1},
+			{Key: "yutong_mqtt.data.total_mileage", Scale: 0.001},
+			{Key: "yutong_mqtt.root.data.total_mileage", Scale: 0.001},
+		}
+	default:
+		return nil
+	}
+}
+
+func TotalMileageKM(protocol envelope.Protocol, fields map[string]any) (float64, bool) {
+	for _, mapping := range MileageFieldMappings(protocol) {
+		value, ok := Number(fields, mapping.Key)
+		if !ok {
+			continue
+		}
+		return value * mapping.Scale, true
+	}
+	return 0, false
+}
+
+func Number(fields map[string]any, key string) (float64, bool) {
+	if len(fields) == 0 {
+		return 0, false
+	}
+	value, ok := fields[key]
+	if !ok || value == nil {
+		return 0, false
+	}
+	switch typed := value.(type) {
+	case float64:
+		return typed, true
+	case float32:
+		return float64(typed), true
+	case int:
+		return float64(typed), true
+	case int8:
+		return float64(typed), true
+	case int16:
+		return float64(typed), true
+	case int32:
+		return float64(typed), true
+	case int64:
+		return float64(typed), true
+	case uint:
+		return float64(typed), true
+	case uint8:
+		return float64(typed), true
+	case uint16:
+		return float64(typed), true
+	case uint32:
+		return float64(typed), true
+	case uint64:
+		return float64(typed), true
+	case json.Number:
+		parsed, err := typed.Float64()
+		return parsed, err == nil
+	case string:
+		parsed, err := strconv.ParseFloat(strings.TrimSpace(typed), 64)
+		return parsed, err == nil
+	default:
+		return 0, false
+	}
+}