#include <WiFi.h>
#include <PubSubClient.h>

// WiFi 配置
const char* ssid = "你的WiFi名称";
const char* password = "你的WiFi密码";

// MQTT 配置
const char* mqtt_server = "broker.hivemq.com"; // 公共测试服务器
const int mqtt_port = 1883;
const char* mqtt_user = ""; // 如果需要认证
const char* mqtt_password = "";

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("正在连接: ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi 连接成功");
  Serial.println("IP 地址: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("收到消息 [");
  Serial.print(topic);
  Serial.print("]: ");
  
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("尝试 MQTT 连接...");
    
    // 客户端 ID
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);
    
    // 尝试连接
    if (client.connect(clientId.c_str(), mqtt_user, mqtt_password)) {
      Serial.println("连接成功");
      
      // 订阅主题
      client.subscribe("esp32/test");
      client.subscribe("esp32/control");
      
    } else {
      Serial.print("失败，错误代码: ");
      Serial.print(client.state());
      Serial.println(" 5秒后重试...");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  setup_wifi();
  
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // 发布消息示例
  static unsigned long lastMsg = 0;
  if (millis() - lastMsg > 5000) {
    lastMsg = millis();
    
    String message = "Hello from ESP32 - " + String(millis());
    client.publish("esp32/status", message.c_str());
    
    Serial.println("消息已发布: " + message);
  }
}

void publishWithQoS() {
  // QoS 0 - 最多一次
  client.publish("esp32/temp", "25.5");
  
  // QoS 1 - 至少一次
  client.publish("esp32/humidity", "60.2", true);
  
  // QoS 2 - 精确一次（需要服务器支持）
  // PubSubClient 默认支持 QoS 0 和 1
}

// 发布保留消息
void publishRetainedMessage() {
  boolean retained = true;
  client.publish("esp32/device/status", "online", retained);
}

// 定义主题
const char* TOPIC_STATUS = "esp32/status";
const char* TOPIC_TEMP = "esp32/sensor/temperature";
const char* TOPIC_HUMIDITY = "esp32/sensor/humidity";
const char* TOPIC_CONTROL = "esp32/control/#";

void setupTopics() {
  // 订阅多个主题
  client.subscribe(TOPIC_CONTROL);
  client.subscribe("esp32/command/#");
}

void callback(char* topic, byte* payload, unsigned int length) {
  String message;
  for (int i = 0; i < length; i++) {
    message += (char)payload[i];
  }
  
  Serial.print("主题: ");
  Serial.print(topic);
  Serial.print(" | 消息: ");
  Serial.println(message);
  
  // 根据主题处理消息
  if (String(topic) == "esp32/control/led") {
    if (message == "ON") {
      digitalWrite(LED_BUILTIN, HIGH);
      client.publish("esp32/status/led", "ON");
    } else if (message == "OFF") {
      digitalWrite(LED_BUILTIN, LOW);
      client.publish("esp32/status/led", "OFF");
    }
  }
}

#include <ArduinoJson.h>

void publishSensorData() {
  StaticJsonDocument<200> doc;
  doc["device"] = "ESP32_001";
  doc["temperature"] = readTemperature();
  doc["humidity"] = readHumidity();
  doc["timestamp"] = millis();
  
  String jsonString;
  serializeJson(doc, jsonString);
  
  client.publish("esp32/sensor/data", jsonString.c_str());
}

#include <WiFiClientSecure.h>

WiFiClientSecure espClient;
PubSubClient client(espClient);

void setup() {
  // ... WiFi 连接代码
  
  // 设置 TLS
  espClient.setCACert(root_ca); // 设置 CA 证书
  
  // 或者跳过证书验证（仅用于测试）
  // espClient.setInsecure();
  
  client.setServer(mqtt_server, 8883); // SSL 端口
}

const char* root_ca = \
"-----BEGIN CERTIFICATE-----\n" \
"你的 CA 证书内容\n" \
"-----END CERTIFICATE-----\n";

#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>

#define DHT_PIN 4
#define DHT_TYPE DHT22

DHT dht(DHT_PIN, DHT_TYPE);

// 配置信息
const char* ssid = "你的WiFi";
const char* password = "你的密码";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

unsigned long lastSensorRead = 0;
const long sensorInterval = 30000; // 30秒

void readAndPublishSensorData() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  
  if (!isnan(temperature) && !isnan(humidity)) {
    char tempStr[8];
    char humStr[8];
    
    dtostrf(temperature, 6, 2, tempStr);
    dtostrf(humidity, 6, 2, humStr);
    
    client.publish("iot/sensor/temperature", tempStr);
    client.publish("iot/sensor/humidity", humStr);
    
    Serial.printf("传感器数据已发布: 温度=%s°C, 湿度=%s%%\n", tempStr, humStr);
  }
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
  
  // 定期读取传感器数据
  if (millis() - lastSensorRead > sensorInterval) {
    lastSensorRead = millis();
    readAndPublishSensorData();
  }
}

// 在 setup() 中配置
void setupMqtt() {
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
  client.setKeepAlive(60);        // 保活时间
  client.setSocketTimeout(30);    // 套接字超时
  client.setBufferSize(1024);     // 缓冲区大小
}