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

// 引脚定义
#define DHTPIN 4       // DHT11数据引脚
#define MQ2PIN 34      // MQ-2模拟输入
#define BUZZER_PIN 25  // 蜂鸣器控制
#define RELAY_PIN 26   // 继电器控制

// 传感器类型
#define DHTTYPE DHT11

// 安全配置
const char* mqttUser = "smart_home_user";  // MQTT用户名
const char* mqttPass = "secure_password123";  // MQTT密码
const char encryptionKey = 0x55;  // 简易加密密钥

// 继电器触发模式
#define RELAY_TRIGGER_MODE HIGH  // LOW=低电平触发，HIGH=高电平触发

// 报警阈值
const int GAS_THRESHOLD = 3650;  // 气体检测阈值

// WiFi和MQTT配置
const char* ssid = "Wokwi-GUEST"; // Wokwi专用WiFi
const char* password = "";
const char* mqttServer = "44.232.241.40"; // 公共MQTT服务器
const int mqttPort = 1883;
const char* mqttTopic = "fjjxu/2025/4/selfmsg";
const char* mqttControlTopic = "fjjxu/2025/4/control"; // 新增控制主题

WiFiClient espClient;
PubSubClient client(espClient);
DHT dht(DHTPIN, DHTTYPE);

// 全局变量
bool alarmState = false;
bool ledState = false;
unsigned long lastBeepTime = 0;
const int beepInterval = 500; // 蜂鸣器间歇时间(ms)

// 简易加密/解密函数（异或加密）
String simpleEncrypt(String input, char key) {
  String output = "";
  for (int i = 0; i < input.length(); i++) {
    output += (char)(input[i] ^ key);
  }
  return output;
}

void setup() {
  Serial.begin(115200);

  // 初始化引脚
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);
  digitalWrite(RELAY_PIN, (RELAY_TRIGGER_MODE == LOW) ? HIGH : LOW);

  // 初始化传感器
  dht.begin();
  
  // 连接WiFi
  connectWiFi();
  
  // 设置MQTT
  client.setServer(mqttServer, mqttPort);
  client.setCallback(mqttCallback);
}

// 连接WiFi函数
void connectWiFi() {
  WiFi.begin(ssid, password);
  Serial.print("正在连接WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi已连接");
  Serial.print("IP地址: ");
  Serial.println(WiFi.localIP());
}

// MQTT回调函数
void mqttCallback(char* topic, byte* payload, unsigned int length) {
  // 将payload转换为字符串并解密
  String encryptedMessage;
  for (int i = 0; i < length; i++) {
    encryptedMessage += (char)payload[i];
  }
  
  String message = simpleEncrypt(encryptedMessage, encryptionKey);
  
  Serial.print("收到消息 [");
  Serial.print(topic);
  Serial.print("]: ");
  Serial.println(message);

  // 处理控制命令
  if (String(topic) == mqttControlTopic) {
    if (message.indexOf("\"led\":1") != -1 || message.indexOf("\"led\":true") != -1) {
      setLedState(true);
    } else if (message.indexOf("\"led\":0") != -1 || message.indexOf("\"led\":false") != -1) {
      setLedState(false);
    }
  }
}

// 设置LED状态函数
void setLedState(bool state) {
  ledState = state;
  digitalWrite(RELAY_PIN, (RELAY_TRIGGER_MODE == LOW) ? !state : state);
  Serial.print("LED状态已更新: ");
  Serial.println(ledState ? "ON" : "OFF");
}

// MQTT重连函数
void reconnect() {
  while (!client.connected()) {
    Serial.print("尝试MQTT连接...");
    if (client.connect("WokwiClient", mqttUser, mqttPass)) {
      Serial.println("已连接");
      client.subscribe(mqttControlTopic);
      Serial.print("已订阅主题: ");
      Serial.println(mqttControlTopic);
    } else {
      Serial.print("失败, rc=");
      Serial.print(client.state());
      Serial.println(" 5秒后重试...");
      delay(5000);
    }
  }
}

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

  // 定时读取传感器数据
  static unsigned long previousMillis = 0;
  const long interval = 2000;
  unsigned long currentMillis = millis();
  
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    readSensors();
  }

  // 串口控制测试
  if (Serial.available()) {
    char cmd = Serial.read();
    if (cmd == '1') setLedState(true);
    else if (cmd == '0') setLedState(false);
  }
}

// 读取传感器数据函数
void readSensors() {
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();
  int gasValue = analogRead(MQ2PIN);

  // 添加随机波动并约束范围
  humidity = constrain(humidity + random(-2, 3), 0, 100);
  temperature = constrain(temperature + random(-2, 3) / 10.0, -10, 50);
  gasValue = constrain(gasValue + random(-50, 60), 0, 5000);

  // 打印传感器数据
  Serial.print("温度: "); Serial.print(temperature); Serial.print("°C");
  Serial.print("  湿度: "); Serial.print(humidity); Serial.print("%");
  Serial.print("  气体值: "); Serial.print(gasValue);
  Serial.print("  LED状态: "); Serial.println(ledState ? "ON" : "OFF");

  // 创建并发送MQTT消息
  String payload = "{\"temperature\":" + String(temperature) +
                 ",\"humidity\":" + String(humidity) +
                 ",\"gasValue\":" + String(gasValue) +
                 ",\"alarm\":" + String(alarmState ? "true" : "false") +
                 ",\"led\":" + String(ledState ? "1" : "0") + "}";
  
  client.publish(mqttTopic, simpleEncrypt(payload, encryptionKey).c_str());

  // 火灾检测
  if (gasValue > GAS_THRESHOLD) {
    triggerAlarm(true);
  } else {
    triggerAlarm(false);
  }
}

// 触发警报函数
void triggerAlarm(bool active) {
  alarmState = active;
  if (active) {
    if (millis() - lastBeepTime >= beepInterval) {
      tone(BUZZER_PIN, 1000, 500);
      lastBeepTime = millis();
      Serial.println("⚠️ 警报触发！");
    }
  } else {
    noTone(BUZZER_PIN);
    Serial.println("✅ 警报停止");
  }
}