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

// Initialize the LCD (address, columns, rows)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Define sensor pins
const int pirPin = esp4; // GPIO 5
const int irPin = D2; // GPIO 4
const int gasSensorPin = A0;
const int ledPin = D6; // GPIO 12
const int fanPin = D7; // GPIO 13
const int dhtPin = D5; // GPIO 14

// Initialize DHT22 sensor
#define DHTTYPE DHT22
DHT dht(dhtPin, DHTTYPE);

// Variables for sensor readings
int pirState = LOW;
int irState = LOW;
int gasLevel = 0;
float temperature = 0.0;
float humidity = 0.0;

void setup() {
  // Initialize LCD
  lcd.begin();
  lcd.backlight();

  // Set sensor pins as input
  pinMode(pirPin, INPUT);
  pinMode(irPin, INPUT);
  pinMode(gasSensorPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(fanPin, OUTPUT);

  // Initialize DHT22 sensor
  dht.begin();

  // Print initial message
  lcd.setCursor(0, 0);
  lcd.print("Smart Classroom");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read PIR sensor
  pirState = digitalRead(pirPin);
  if (pirState == HIGH) {
    lcd.setCursor(0, 0);
    lcd.print("Motion Detected  ");
    digitalWrite(ledPin, HIGH); // Turn on LED when motion is detected
  } else {
    lcd.setCursor(0, 0);
    lcd.print("No Motion        ");
    digitalWrite(ledPin, LOW); // Turn off LED when no motion
  }

  // Read IR sensor
  irState = digitalRead(irPin);
  if (irState == HIGH) {
    lcd.setCursor(0, 1);
    lcd.print("IR Signal Detected");
  } else {
    lcd.setCursor(0, 1);
    lcd.print("No IR Signal     ");
  }

  // Read Gas sensor
  gasLevel = analogRead(gasSensorPin);
  if (gasLevel > 300) { // Adjust threshold as needed
    lcd.setCursor(0, 1);
    lcd.print("Gas Detected!    ");
    // Additional actions can be added here (e.g., triggering an alarm)
  }

  // Read DHT22 sensor
  temperature = dht.readTemperature();
  humidity = dht.readHumidity();
  
  if (isnan(temperature) || isnan(humidity)) {
    lcd.setCursor(0, 0);
    lcd.print("DHT22 Error      ");
  } else {
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    lcd.print(temperature);
    lcd.print("C ");
    lcd.setCursor(0, 1);
    lcd.print("Hum: ");
    lcd.print(humidity);
    lcd.print("% ");
  }

  // Control fan based on temperature
  if (temperature > 25.0) { // Adjust threshold as needed
    digitalWrite(fanPin, HIGH); // Turn on the fan
  } else {
    digitalWrite(fanPin, LOW); // Turn off the fan
  }

  // Small delay for sensor stability
  delay(2000); // Increased delay to allow reading to be visible on LCD
}