#include <LiquidCrystal_I2C.h>
#include <DHT.h>

// 定义传感器和执行器的引脚
#define DHTPIN 6 // DHT22传感器的引脚
#define GAS_SENSOR_PIN A0
#define LDR_PIN A1
#define DUST_SENSOR_PIN A2

#define GAS_SWITCH_PIN 2
#define DUST_SWITCH_PIN 3
#define LIGHT_SWITCH_PIN 4

// 定义LED和继电器的连接pin
#define LED_PIN 13
#define RELAY_PIN 12

// 定义传感器类型
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// 实例化LCD显示屏
LiquidCrystal_I2C lcd(0x27, 20, 4);

// 设定阈值
const int TEMP_THRESHOLD = 25; // 温度阈值
const float HUMIDITY_THRESHOLD = 60.0; // 湿度阈值
const int GAS_THRESHOLD = 300; // 假定气体阈值
const int DUST_THRESHOLD = 100; // 粉尘阈值
const int LIGHT_THRESHOLD = 800; // 光敏阈值

void setup() {
  pinMode(GAS_SWITCH_PIN, INPUT_PULLUP);
  pinMode(DUST_SWITCH_PIN, INPUT_PULLUP);
  pinMode(LIGHT_SWITCH_PIN, INPUT_PULLUP);

  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(GAS_SENSOR_PIN, INPUT);
  pinMode(DUST_SENSOR_PIN, INPUT);

  dht.begin();
  lcd.init();
  lcd.backlight();
  
  digitalWrite(RELAY_PIN, LOW); // 默认关闭风扇
  
  // 初始化串口通信
  Serial.begin(9600);
}

void loop() {
  // 读取传感器数据
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // 使用三元运算符判断是否读取或显示nan
  int gasLevel = digitalRead(GAS_SWITCH_PIN) ? analogRead(GAS_SENSOR_PIN) : -1;
  int lightIntensity = digitalRead(LIGHT_SWITCH_PIN) ? analogRead(LDR_PIN) : -1;
  int dustDensity = digitalRead(DUST_SWITCH_PIN) ? analogRead(DUST_SENSOR_PIN) : -1;

  // 显示传感器数据
  displaySensorData(temperature, humidity, gasLevel, lightIntensity, dustDensity);

  // 根据阈值控制LED和继电器
  checkThresholdsAndControl(temperature, humidity, gasLevel, lightIntensity, dustDensity);

  delay(1000); // 更新频率为1秒
}


void displaySensorData(float temperature, float humidity, int gas, int light, int dust) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(temperature);
  lcd.print(" ");

  lcd.setCursor(10, 0);
  lcd.print("H:");
  lcd.print(humidity);
  lcd.print(" ");

  lcd.setCursor(0, 1);
  if (gas >= 0) {
    lcd.print("Gas:");
    lcd.print(gas);
  } else {
    lcd.print("Gas: nan");
  }
  lcd.print(" ");

  lcd.setCursor(0, 2);
  if (light >= 0) {
    lcd.print("Light:");
    lcd.print(light);
  } else {
    lcd.print("Light: nan");
  }
  lcd.print(" ");

  lcd.setCursor(0, 3);
  if (dust >= 0) {
    lcd.print("Dust:");
    lcd.print(dust);
  } else {
    lcd.print("Dust: nan");
  }
  lcd.print(" ");
}

void checkThresholdsAndControl(float temperature, float humidity, int gas, int light, int dust) {
  // 示例：如果温度大于25度，打开通风
  if(temperature > 25) {
     digitalWrite(RELAY_PIN, HIGH); // 打开风扇
  } else {
     digitalWrite(RELAY_PIN, LOW); // 关闭风扇
  }

  // 根据其它阈值进行类似的控制...
  // 高气体浓度或光强度过高，或者粉尘过多时控制LED和风扇
  
  if(gas > 300 || light > 800 || dust > 500) { // 这些阈值需要你根据实际情况调整
     digitalWrite(LED_PIN, !digitalRead(LED_PIN)); // LED灯闪烁
     digitalWrite(RELAY_PIN, HIGH); // 打开风扇
  } else {
    digitalWrite(LED_PIN, LOW);
  }
}