#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Servo.h>

// Initialize LCD with I2C address (Check with I2C scanner: usually 0x27 or 0x3F)
LiquidCrystal_I2C lcd(0x27, 16, 2); 

// Keypad configuration
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {9, 8, 7, 6}; 
byte colPins[COLS] = {5, 4, 3, 2}; 

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Define Components
Servo doorLock;
#define BUZZER 11
#define RED_LED 12
#define GREEN_LED 13

// Set a fixed PIN for unlocking the door
String password = "1234";  // Change this to your desired password
String inputPassword = "";

void setup() {
  Serial.begin(9600);

  lcd.begin(16, 2);  // Initialize LCD
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Smart Door Lock");

  pinMode(BUZZER, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);

  digitalWrite(RED_LED, HIGH);
  digitalWrite(GREEN_LED, LOW);

  doorLock.attach(10);
  doorLock.write(0); // Locked position
}

void loop() {
  lcd.setCursor(0, 1);
  lcd.print("Enter PIN: ");
  
  char key = keypad.getKey();
  if (key) {
    Serial.print(key);
    
    if (key == '*') { 
      inputPassword = ""; // Clear input on '*'
      lcd.setCursor(0, 1);
      lcd.print("Enter PIN:      "); // Clear previous input
    } 
    else if (key == '#') {
      checkPassword(); // Validate input
    } 
    else {
      inputPassword += key;
      lcd.setCursor(10, 1);
      lcd.print(inputPassword);
    }
  }
}

void checkPassword() {
  lcd.setCursor(0, 1);
  lcd.print("Checking...    ");
  delay(1000);

  if (inputPassword == password) {
    unlockDoor();
  } 
  else {
    lcd.setCursor(0, 1);
    lcd.print("Access Denied! ");
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    tone(BUZZER, 1000, 500);  // Buzzer alert
    delay(2000);
  }

  inputPassword = "";  // Reset password input
  lcd.setCursor(0, 1);
  lcd.print("Enter PIN:      ");
}

void unlockDoor() {
  lcd.setCursor(0, 1);
  lcd.print("Access Granted!");
  
  digitalWrite(RED_LED, LOW);
  digitalWrite(GREEN_LED, HIGH);
  tone(BUZZER, 500, 300);

  doorLock.write(90); // Unlock position
  delay(5000);  // Keep door open for 5 seconds

  doorLock.write(0); // Lock position
  lcd.setCursor(0, 1);
  lcd.print("Enter PIN:      ");
}