#include <Wire.h>              // Include library to communicate with I2C devices
#include <LiquidCrystal_I2C.h>  // Include LCD library to control I2C LCD
#include <DHT.h>                // Include DHT sensor library
#include <ESP32Servo.h>         // Include Servo motor library

// Define DHT sensor pin and type
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);  // Initialize DHT sensor

// Initialize LCD (I2C) with address and size
LiquidCrystal_I2C lcd(0x27, 20, 4);  // LCD with I2C address 0x27, 20 columns and 4 rows

// Initialize Servo motors
Servo tempServo;
Servo humidityServo;
Servo buttonServo;

// Pin definitions for button, PIR sensor, LED, and buzzer
#define BUTTONPIN 14
#define PIRPIN 13
#define LEDPIN 12
#define BUZZERPIN 27

// Set thresholds for temperature and humidity
const float tempThreshold = 27.0;  // Temperature threshold in Celsius
const float humThreshold = 60.0;   // Humidity threshold in percentage

void setup() {
  Serial.begin(115200);  // Initialize serial monitor for debugging

  // Initialize LCD screen
  lcd.init();             // Set up LCD
  lcd.backlight();       // Turn on backlight
  lcd.clear();           // Clear screen
  lcd.print("Initializing...");  // Display message
  delay(2000);           // Wait for 2 seconds

  // Initialize DHT sensor
  dht.begin();
  Serial.println("DHT Sensor Initialized");

  // Initialize servo motors for controlling devices based on temperature and humidity
  tempServo.attach(18);         // Temperature control servo
  humidityServo.attach(19);     // Humidity control servo
  buttonServo.attach(23);       // Button press control servo

  // Set pin modes for inputs and outputs
  pinMode(PIRPIN, INPUT);       // PIR sensor input pin
  pinMode(LEDPIN, OUTPUT);      // LED output pin
  pinMode(BUTTONPIN, INPUT_PULLUP);  // Button input pin (with pull-up resistor)
  pinMode(BUZZERPIN, OUTPUT);   // Buzzer output pin

  delay(2000);  // Wait for 2 seconds to stabilize
  lcd.clear();  // Clear the screen
}

void loop() {
  // Read temperature and humidity from the DHT sensor
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Print values to Serial Monitor for debugging
  Serial.print("Temperature: ");
  Serial.println(temperature);
  Serial.print("Humidity: ");
  Serial.println(humidity);

  // Check if sensor readings are valid
  if (isnan(temperature) || isnan(humidity)) {
    lcd.setCursor(0, 0);
    lcd.print("Sensor Error!   ");  // Display error if sensor reading fails
    delay(2000);  // Wait 2 seconds before retrying
    return;  // Skip the rest of the loop and try again
  }

  // Display temperature and humidity on the LCD without clearing the screen
  lcd.setCursor(0, 0);  // Set cursor to top-left of the screen
  lcd.print("Temp: ");
  lcd.print(temperature, 1);  // Display temperature with 1 decimal place
  lcd.print(" C");

  lcd.setCursor(0, 1);  // Move cursor to the next row
  lcd.print("Humidity: ");
  lcd.print(humidity, 1);  // Display humidity with 1 decimal place
  lcd.print(" %");

  // Temperature Control
  if (temperature >= tempThreshold) {
    tempServo.write(90); // Move the servo when temp is above threshold
  } else {
    tempServo.write(0); // Reset the servo when temp is below threshold
  }

  // Humidity Control
  if (humidity >= humThreshold) {
    humidityServo.write(90); // Move the servo when humidity is above threshold
  } else {
    humidityServo.write(0); // Reset the servo when humidity is below threshold
  }

// PIR Motion Detection
  if (digitalRead(PIRPIN) == HIGH) {
    digitalWrite(LEDPIN, HIGH);  // Turn on LED when motion is detected
  } else {
    digitalWrite(LEDPIN, LOW);   // Turn off LED when no motion
  }
  
  // Button Press Logic
  if (digitalRead(BUTTONPIN) == LOW) {  // Button is pressed
    buttonServo.write(90);   // Move the servo when button is pressed
    tone(BUZZERPIN, 1000, 1000);  // Activate buzzer for 500ms
    delay(500);  // Wait before continuing
    buttonServo.write(0);
  } else {
    buttonServo.write(0);   // Reset servo when button is not pressed
  }

  delay(1000);  // Delay for stable readings and smooth operation
}