feat: add go vehicle identity resolver

go/vehicle-gateway/internal/identity/resolver.go

@@ -0,0 +1,112 @@
+package identity
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"strings"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+type Resolver interface {
+	Resolve(context.Context, envelope.FrameEnvelope) (envelope.FrameEnvelope, error)
+}
+
+type NoopResolver struct{}
+
+func (NoopResolver) Resolve(_ context.Context, env envelope.FrameEnvelope) (envelope.FrameEnvelope, error) {
+	return env, nil
+}
+
+type MySQLResolver struct {
+	db    *sql.DB
+	table string
+}
+
+func NewMySQLResolver(db *sql.DB, table string) *MySQLResolver {
+	if db == nil {
+		panic("identity db must not be nil")
+	}
+	table = strings.TrimSpace(table)
+	if table == "" || !safeIdentifier(table) {
+		table = "vehicle_identity_binding"
+	}
+	return &MySQLResolver{db: db, table: table}
+}
+
+func safeIdentifier(value string) bool {
+	if value == "" {
+		return false
+	}
+	for _, r := range value {
+		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' {
+			continue
+		}
+		return false
+	}
+	return true
+}
+
+func (r *MySQLResolver) Resolve(ctx context.Context, env envelope.FrameEnvelope) (envelope.FrameEnvelope, error) {
+	if strings.TrimSpace(env.VIN) != "" {
+		return env, nil
+	}
+	candidates := CandidateKeys(env)
+	for _, candidate := range candidates {
+		vin, err := r.lookup(ctx, candidate.Column, candidate.Value)
+		if err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				continue
+			}
+			return env, err
+		}
+		if strings.TrimSpace(vin) != "" {
+			env.VIN = strings.TrimSpace(vin)
+			if env.Parsed == nil {
+				env.Parsed = map[string]any{}
+			}
+			env.Parsed["identity"] = map[string]any{
+				"resolved": true,
+				"source":   candidate.Column,
+				"value":    candidate.Value,
+			}
+			env.EventID = env.StableEventID()
+			return env, nil
+		}
+	}
+	return env, nil
+}
+
+func (r *MySQLResolver) lookup(ctx context.Context, column string, value string) (string, error) {
+	query := "SELECT vin FROM " + r.table + " WHERE " + column + " = ? AND vin IS NOT NULL AND vin <> '' ORDER BY updated_at DESC LIMIT 1"
+	var vin string
+	err := r.db.QueryRowContext(ctx, query, value).Scan(&vin)
+	return vin, err
+}
+
+type CandidateKey struct {
+	Column string
+	Value  string
+}
+
+func CandidateKeys(env envelope.FrameEnvelope) []CandidateKey {
+	var out []CandidateKey
+	add := func(column string, value string) {
+		value = strings.TrimSpace(value)
+		if value == "" || strings.EqualFold(value, "unknown") {
+			return
+		}
+		for _, existing := range out {
+			if existing.Column == column && existing.Value == value {
+				return
+			}
+		}
+		out = append(out, CandidateKey{Column: column, Value: value})
+	}
+	add("phone", env.Phone)
+	add("device_id", env.DeviceID)
+	add("plate", env.Plate)
+	add("vin", env.VehicleKeyHint)
+	return out
+}