#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>

// Define pins for each component
#define DHTPIN 4
#define DHTTYPE DHT22
#define RED 16
#define BLUE 2
#define BUZZER 25
#define SERVO 19

// Define the highest range of temperature and humidity
#define highest_temp 30 // in Celsius
#define highest_humidity 70 // in percentage

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 4);
Servo ESP32Servo;

void setup() {
  // Initialize components
  dht.begin();
  lcd.init();
  lcd.backlight();
  ESP32Servo.attach(SERVO);
  pinMode(RED, OUTPUT);
  pinMode(BLUE, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() {
  // Read temperature and humidity using the libraries of dht
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  //error handling for the sensor
  if (isnan(temp) || isnan(hum)) {
    lcd.setCursor(0, 0);
    lcd.print("Sensor Error!");
    delay(2000);
    return;
  }
  //conditional statement to know if the temperature exceeded the limit set
  if (temp >= highest_temp) {
    digitalWrite(RED, HIGH);
  } else {
    digitalWrite(RED, LOW);
  }
  //conditional statement to know if the humidity exceeded the limit set
  if (hum >= highest_humidity) {
    digitalWrite(BLUE, HIGH);
  } else {
    digitalWrite(BLUE, LOW);
  }

  //condtion to know if it's time to open the exhaust fan
  if (temp >= highest_temp && hum >= highest_humidity) {
    digitalWrite(BUZZER, HIGH);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WARNING: HIGH T&H");
    lcd.setCursor(0, 2);
    lcd.print("Opening Exhaust");
    ESP32Servo.write(0); // open exhaust fan
    for (int i = 0; i < 5; i++) { // Blink 5 times
      digitalWrite(RED, HIGH);
      digitalWrite(BLUE, HIGH);
      delay(300); // On for 300ms
      digitalWrite(RED, LOW);
      digitalWrite(BLUE, LOW);
      delay(300); // Off for 300ms
    }
    delay(3000); 
    
  } else {
    // Temperature or humidity is normal or have not reached the limit yet
    digitalWrite(BUZZER, LOW);
    ESP32Servo.write(90); //closed exhaust fan
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("T&H is now normal");
    lcd.setCursor(0, 2);
    lcd.print("Closing Exhaust");

    delay(3000); 
  }

  // Real-time display for the temperature and humidity
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temperature: ");
  lcd.print(temp);
  lcd.print("C");

  lcd.setCursor(0, 2);
  lcd.print("Humidity: ");
  lcd.print(hum);
  lcd.print("%");

  delay(5000); // Refresh every 5 seconds
}