fix(mqtt): improve topic parsing logic and dynamic clientid logging

mqtt-gateway/internal/handler/mqtt_handler.go

@@ -29,11 +29,26 @@ func (h *MqttHandler) HandleMessage(client mqtt.Client, msg mqtt.Message) {
 	// 檢查是否為系統主題 ($SYS)
 	if strings.HasPrefix(topic, "$SYS/") {
 		parts := strings.Split(topic, "/")
-		if len(parts) >= 6 {
-			serialNo = parts[4]
-			event := parts[5]
+		
+		// 尋找事件類型 (connected 或 disconnected)
+		var event string
+		for _, p := range parts {
+			if p == "connected" || p == "disconnected" {
+				event = p
+				break
+			}
+		}
 
-			// 解析系統 JSON Payload
+		// 尋找 Client ID (通常位於 "clients" 的下一層)
+		for i, p := range parts {
+			if p == "clients" && i+1 < len(parts) {
+				serialNo = parts[i+1]
+				break
+			}
+		}
+
+		if event != "" && serialNo != "" {
+			// 解析系統 JSON Payload (補強：有些版本會把 ClientID 放在 Payload 裡)
 			var sysData map[string]interface{}
 			if err := json.Unmarshal(payload, &sysData); err == nil {
 				if cid, ok := sysData["clientid"].(string); ok {

mqtt-gateway/main.go

@@ -54,7 +54,7 @@ func main() {
 	opts.SetMaxReconnectInterval(10 * time.Second)
 
 	opts.SetOnConnectHandler(func(c mqtt.Client) {
-		log.Printf("Connected to MQTT Broker as Gateway [star-cloud-gateway] at %s", cfg.MQTTAddr)
+		log.Printf("Connected to MQTT Broker as Gateway [%s] at %s", cfg.MQTTClientID, cfg.MQTTAddr)
 		// 訂閱所有機台的上行 Topic
 		token := c.Subscribe("machine/+/+", 1, mqttHandler.HandleMessage)
 		token.Wait()