#include <WiFi.h>
#include <PubSubClient.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <time.h>

// 定义传感器引脚和类型
#define DHTPIN 26
#define DHTTYPE DHT22
#define BUTTON_PIN 14  // 按钮输入引脚
#define LED_PIN 19     // LED输出引脚

// WiFi和MQTT配置
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";

// MQTT主题定义
const char* mqtt_topic_pub = "IoT/WXP/sensor";     // 发布温湿度数据
const char* mqtt_topic_time = "IoT/WXP/time";       // 发布时间数据
const char* mqtt_topic_sub = "IoT/WXP/led";         // 订阅LED控制命令
const char* mqtt_topic_alarm = "IoT/WXP/alarm";     // 发布告警信息
const char* mqtt_topic_lwt = "IoT/WXP/status";      // 遗嘱消息主题(设备状态)

// 创建客户端和传感器对象
WiFiClient espClient;
PubSubClient client(espClient);
DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 20, 4); // 使用20x4 LCD

// 全局变量
bool ledState = false;               // LED当前状态
unsigned long lastMsg = 0;           // 上次发布消息时间
unsigned long lastButtonTime = 0;    // 上次按钮操作时间
unsigned long lastDisplayChange = 0; // 上次显示更新时间
const long publishInterval = 5000;   // 5秒定时发布间隔
const long idleTimeToSleep = 60000;  // 1分钟无操作进入休眠
const long displayInterval = 5000;   // 5秒切换显示内容

int displayState = 0; // 0:欢迎, 1:时间, 2:温湿度
char msg[100];        // MQTT消息缓冲区

// 自定义温度点字符(用于LCD显示℃符号)
uint8_t dot[] = {0x0E, 0x0A, 0x0E, 0x00, 0x00, 0x00, 0x00, 0x00};

// 连接WiFi网络
void setup_wifi() {
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);
  // 等待WiFi连接
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  Serial.println("\nWiFi connected successfully!");
}

// MQTT消息回调函数，处理订阅的消息
void callback(char* topic, byte* payload, unsigned int length) {
  payload[length] = 0;  // 确保字符串以空字符结尾
  String command = String((char*)payload);
  command.toUpperCase();  // 转换为大写方便比较
  Serial.print("Received command: ");
  Serial.println(command);
  
  // 处理LED控制命令
  if (command == "ON") {
    digitalWrite(LED_PIN, HIGH);
    ledState = true;
    Serial.println("LED turned ON via MQTT command");
  } else if (command == "OFF") {
    digitalWrite(LED_PIN, LOW);
    ledState = false;
    Serial.println("LED turned OFF via MQTT command");
  }
}

// 重新连接MQTT服务器(带重试间隔控制)
void reconnect() {
  // 增加重连间隔控制，避免频繁重试
  static unsigned long lastReconnectAttempt = 0;
  const long reconnectInterval = 5000; // 5秒重试间隔
  
  if (millis() - lastReconnectAttempt < reconnectInterval) {
    return; // 未到重试时间
  }
  lastReconnectAttempt = millis();

  Serial.println("Connecting to MQTT...");
  // 连接MQTT服务器，设置遗嘱消息
  if (client.connect("ESP32ClientDevice", mqtt_topic_lwt, 0, true, "offline")) {
    Serial.println("MQTT connected successfully");
    client.publish(mqtt_topic_lwt, "online", true); // 发布在线状态
    client.subscribe(mqtt_topic_sub); // 订阅LED控制主题
    
    // 设置更长的KeepAlive时间和socket超时，提高稳定性
    client.setKeepAlive(60);
    client.setSocketTimeout(30);
  } else {
    Serial.print("MQTT connection failed, status=");
    Serial.print(client.state());
    Serial.println(", will retry later");
  }
}

// 在LCD上显示欢迎信息
void displayWelcome() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("ESP32!");
  lcd.setCursor(0, 1);
  lcd.print("Hello, World!");
}

// 在LCD上显示当前日期和时间，并发布到MQTT
void displayDateTime() {
  struct tm timeinfo;
  if (getLocalTime(&timeinfo)) {
    char dtbuf[21];
    // 格式化时间为"YYYY-MM-DD HH:MM:SS"
    strftime(dtbuf, sizeof(dtbuf), "%Y-%m-%d %H:%M:%S", &timeinfo);
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Current DateTime:");
    lcd.setCursor(0, 1);
    lcd.print(dtbuf);
    
    // 发布时间到MQTT
    client.publish(mqtt_topic_time, dtbuf);
  }
}

// 在LCD上显示温湿度数据，并发布到MQTT
void displayTempHumidity() {
  // 在读取传感器前检查是否超时，避免长时间操作导致休眠
  unsigned long start = millis();
  
  // 读取温湿度数据
  float h = dht.readHumidity();
  float c = dht.readTemperature();
  float f = dht.readTemperature(true);
  
  // 如果读取时间过长，直接返回不更新显示
  if (millis() - start > 1000) {
    return;
  }
  
  // 检查读取是否成功
  if (isnan(h) || isnan(c) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sensor Error!");
    return;
  }

  // 打印温湿度数据到串口
  Serial.printf(
    "Humidity: %.1f  Temperature: %.1f deg C  %.1f deg F\n",
    h, c, f
  );

  // 在LCD上显示温湿度数据
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Humidity: "); lcd.print(h, 1); lcd.print("%");
  
  lcd.setCursor(0, 1);
  lcd.print("Temperature: "); lcd.print(c, 2); lcd.write(0); lcd.print("C");

  lcd.setCursor(0, 2);
  lcd.print("Temperature: "); lcd.print(f, 1); lcd.write(0); lcd.print("F");

  // 发布温湿度数据到MQTT(JSON格式)
  snprintf(msg, sizeof(msg), "{\"temp\": %.1f, \"hum\": %.1f}", c, h);
  client.publish(mqtt_topic_pub, msg);
}

// 初始化函数，系统启动时执行一次
void setup() {
  Serial.begin(115200);
  Serial.println("Starting setup()...");

  // 配置IO引脚
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW); // 初始关闭LED

  // 初始化LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  
  // 创建自定义字符(℃符号)
  lcd.createChar(0, dot);

  // 初始化传感器和网络
  dht.begin();
  setup_wifi();

  // 配置MQTT客户端
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);

  // 配置NTP时间同步 (UTC+8时区)
  configTime(8 * 3600, 0, "pool.ntp.org");
  struct tm timeinfo;
  // 等待时间同步完成
  while (!getLocalTime(&timeinfo)) {
    Serial.println("Waiting for time sync...");
    delay(1000);
  }
  Serial.println("Time synchronized successfully");

  // 初始化计时器和显示
  lastButtonTime = millis();
  lastDisplayChange = millis();
  displayWelcome();

  Serial.println("setup() complete, entering loop()");
}

// 主循环，系统启动后不断循环执行
void loop() {
  // 检查MQTT连接，必要时重连
  if (!client.connected()) {
    reconnect();
  }
  // 处理MQTT网络事件
  client.loop();

  unsigned long now = millis();
  
  // 按钮检测（使用非阻塞方式）
  if (digitalRead(BUTTON_PIN) == LOW) {
    delay(50); // 简单消抖
    if (digitalRead(BUTTON_PIN) == LOW) { // 确认按钮按下
      // 切换LED状态
      ledState = !ledState;
      digitalWrite(LED_PIN, ledState);
      Serial.print("Button pressed, LED toggled to: ");
      Serial.println(ledState ? "ON" : "OFF");
      // 发布按钮按下告警到MQTT
      client.publish(mqtt_topic_alarm, "Button pressed!");
      
      // 重置计时器，避免休眠
      lastButtonTime = now;
      lastDisplayChange = now;
      
      // 等待按钮释放
      while (digitalRead(BUTTON_PIN) == LOW) {
        delay(10);
        // 在等待按钮释放期间持续更新计时器，防止休眠
        now = millis();
        lastButtonTime = now;
      }
    }
  }

  // 检查是否超时无操作，进入休眠状态
  if (now - lastButtonTime > idleTimeToSleep) {
    Serial.println("Idle timeout reached, entering light sleep...");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sleeping 10s...");
    
    // 设置30秒后唤醒
    esp_sleep_enable_timer_wakeup(30 * 1000000ULL);
    Serial.println("Entering light sleep now.");
    esp_light_sleep_start(); // 进入浅睡眠模式
    
    // 唤醒后执行的代码
    Serial.println("Woke up from light sleep!");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Woke up!");
    delay(500);
    
    // 重置状态和计时器
    lastButtonTime = millis();
    lastDisplayChange = millis();
    displayState = 0;
    displayWelcome();
    return; // 从loop函数返回，重新开始循环
  }

  // 显示内容轮换控制
  if (now - lastDisplayChange >= displayInterval) {
    lastDisplayChange = now;
    displayState = (displayState + 1) % 3; // 循环切换显示状态
    
    // 根据当前显示状态更新LCD内容
    switch (displayState) {
      case 0: displayWelcome(); break;
      case 1: displayDateTime(); break;
      case 2: displayTempHumidity(); break;
    }
  }
}