fix: support extended gb32960 platform login

go/vehicle-gateway/internal/protocol/gb32960/parser.go

@@ -38,7 +38,7 @@ func ExtractFrames(stream []byte) (frames [][]byte, remainder []byte, err error)
 			return frames, append([]byte(nil), remaining...), nil
 		}
 		bodyLen := int(binary.BigEndian.Uint16(remaining[22:24]))
-		frameLen := headerLen + bodyLen + 1
+		frameLen := frameLength(remaining, bodyLen)
 		if len(remaining) < frameLen {
 			return frames, append([]byte(nil), remaining...), nil
 		}
@@ -59,7 +59,8 @@ func ParseFrame(raw []byte, receivedAtMS int64, sourceEndpoint string) (envelope
 		return envelope.FrameEnvelope{}, fmt.Errorf("%w: %s", ErrBadStartSymbol, hex.EncodeToString(raw[:2]))
 	}
 	bodyLen := int(binary.BigEndian.Uint16(raw[22:24]))
-	if len(raw) != headerLen+bodyLen+1 {
+	actualBodyLen := len(raw) - headerLen - 1
+	if len(raw) != headerLen+bodyLen+1 && !isExtendedPlatformLogin(raw[2], bodyLen, actualBodyLen) {
 		return envelope.FrameEnvelope{}, fmt.Errorf("%w: declared=%d actual=%d", ErrBodyLength, bodyLen, len(raw)-headerLen-1)
 	}
 	if got, want := bcc(raw[2:len(raw)-1]), raw[len(raw)-1]; got != want {
@@ -69,15 +70,16 @@ func ParseFrame(raw []byte, receivedAtMS int64, sourceEndpoint string) (envelope
 	command := raw[2]
 	responseFlag := raw[3]
 	vin := strings.TrimRight(string(raw[4:21]), "\x00 ")
-	body := raw[headerLen : headerLen+bodyLen]
+	body := raw[headerLen : headerLen+actualBodyLen]
 	parsed := map[string]any{
 		"header": map[string]any{
-			"version":       version,
-			"command":       fmt.Sprintf("0x%02X", command),
-			"response_flag": fmt.Sprintf("0x%02X", responseFlag),
-			"vin":           vin,
-			"encrypt":       raw[21],
-			"body_length":   bodyLen,
+			"version":            version,
+			"command":            fmt.Sprintf("0x%02X", command),
+			"response_flag":      fmt.Sprintf("0x%02X", responseFlag),
+			"vin":                vin,
+			"encrypt":            raw[21],
+			"body_length":        bodyLen,
+			"actual_body_length": actualBodyLen,
 		},
 	}
 	fields := map[string]any{}
@@ -91,6 +93,16 @@ func ParseFrame(raw []byte, receivedAtMS int64, sourceEndpoint string) (envelope
 			parsed["device_time"] = eventTime.Format(time.RFC3339)
 		}
 		parsed["data_units"] = units
+	} else if command == 0x05 {
+		login := parsePlatformLogin(body)
+		parsed["platform_login"] = login
+		if deviceTime, ok := login["login_time"].(string); ok && deviceTime != "" {
+			fields["device_time"] = deviceTime
+			parsed["device_time"] = deviceTime
+		}
+		if account, ok := login["username"].(string); ok && account != "" {
+			fields["platform_account"] = account
+		}
 	}
 
 	env := envelope.FrameEnvelope{
@@ -113,7 +125,7 @@ func parseDataBody(version string, body []byte, fields map[string]any) (time.Tim
 	if len(body) < 6 {
 		return time.Time{}, nil
 	}
-	eventTime := parseBCDTime(body[:6])
+	eventTime := parseGBTime(body[:6])
 	cursor := 6
 	var units []map[string]any
 	for cursor < len(body) {
@@ -303,6 +315,54 @@ func parseDataBody(version string, body []byte, fields map[string]any) (time.Tim
 	return eventTime, units
 }
 
+func frameLength(frameStart []byte, bodyLen int) int {
+	standardLen := headerLen + bodyLen + 1
+	if len(frameStart) < headerLen || frameStart[2] != 0x05 || bodyLen != 41 {
+		return standardLen
+	}
+	// Some field platform-login frames declare the standard 41-byte body but
+	// carry a 32-byte password, making the actual body 53 bytes. Only consume
+	// the extended form when its own BCC verifies so the splitter does not eat
+	// bytes from the next frame.
+	extendedLen := headerLen + 53 + 1
+	if len(frameStart) < extendedLen {
+		return standardLen
+	}
+	extended := frameStart[:extendedLen]
+	if bcc(extended[2:len(extended)-1]) == extended[len(extended)-1] {
+		return extendedLen
+	}
+	return standardLen
+}
+
+func isExtendedPlatformLogin(command byte, declaredBodyLen int, actualBodyLen int) bool {
+	return command == 0x05 && declaredBodyLen == 41 && actualBodyLen == 53
+}
+
+func parsePlatformLogin(body []byte) map[string]any {
+	login := map[string]any{
+		"raw_body_length": len(body),
+	}
+	if len(body) < 9 {
+		login["error"] = "truncated"
+		return login
+	}
+	loginTime := parseGBTime(body[:6])
+	if !loginTime.IsZero() {
+		login["login_time"] = loginTime.Format(time.RFC3339)
+	}
+	login["serial_no"] = binary.BigEndian.Uint16(body[6:8])
+	if len(body) >= 21 {
+		login["username"] = trimASCII(body[8:20])
+	}
+	if len(body) > 21 {
+		passwordEnd := len(body) - 1
+		login["password"] = trimASCII(body[20:passwordEnd])
+		login["encrypt_rule"] = body[passwordEnd]
+	}
+	return login
+}
+
 func parseVehicleData(data []byte) map[string]any {
 	return map[string]any{
 		"vehicle_status":   int(data[0]),
@@ -751,24 +811,24 @@ func version(a byte, b byte) (string, bool) {
 	}
 }
 
-func parseBCDTime(data []byte) time.Time {
+func parseGBTime(data []byte) time.Time {
 	if len(data) != 6 {
 		return time.Time{}
 	}
-	year := 2000 + bcdByte(data[0])
-	month := time.Month(bcdByte(data[1]))
-	day := bcdByte(data[2])
-	hour := bcdByte(data[3])
-	minute := bcdByte(data[4])
-	second := bcdByte(data[5])
+	year := 2000 + int(data[0])
+	month := time.Month(data[1])
+	day := int(data[2])
+	hour := int(data[3])
+	minute := int(data[4])
+	second := int(data[5])
 	if month < 1 || month > 12 || day < 1 || day > 31 || hour > 23 || minute > 59 || second > 59 {
 		return time.Time{}
 	}
 	return time.Date(year, month, day, hour, minute, second, 0, time.FixedZone("Asia/Shanghai", 8*3600))
 }
 
-func bcdByte(value byte) int {
-	return int(value>>4)*10 + int(value&0x0f)
+func trimASCII(data []byte) string {
+	return strings.TrimRight(string(data), "\x00 ")
 }
 
 func bcc(data []byte) byte {