const messageId = "sts_" + Date.now();
const timestamp = Date.now();
//nameSpace：命名空间，需要改改为正确的命名空间代码
const nameSpace = "Environment"
const clientCode = "Data-It_XzOffice";
//此处需改为正确的设备实体唯一ID
const deviceId = "sensor.miaomiaoc_cn_blt_3_11a1sbr5k5o01_t2_temperature_p_2_1";
const deviceType = "sensor";

// 计算设备运行时间（从第一次启动开始）
if (!context.get("startTime")) {
    context.set("startTime", timestamp);
}
const startTime = context.get("startTime");
const uptime = timestamp - startTime;

// 按照胜透物联网通信协议生成状态数据
const statusMessage = {
    "messageId": messageId,
    "timestamp": timestamp,
    "clientCode": clientCode,
    "deviceId": deviceId,
    "deviceType": deviceType,
    "version": "1.0",
    "data": {
        "status": {
            "online": true,
            "lastHeartbeat": timestamp,
            "uptime": uptime
        }
    }
};

// 设置MQTT发布主题
msg.topic = `${nameSpace}/${deviceType}/${deviceId}/status`;
msg.payload = JSON.stringify(statusMessage);
msg.qos = 0;

node.log("设备状态心跳已发送，发布到主题: " + msg.topic);

return msg;