#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>
const int PASSWORD_LENGTH = 4;
const int PASSWORD[PASSWORD_LENGTH] = {1, 2, 3, 4};  
const int SERVO_PIN = 11;
const int BUZZER_PIN = 12;
LiquidCrystal_I2C lcd(0x3f,16,2);
Servo servo;

// Keypad pins
const int ROW_PINS[4] = {9, 8, 7, 6};
const int COL_PINS[4] = {5, 4, 3, 2};

char KEYS[4][4] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
int passwordInput[PASSWORD_LENGTH];
int currentDigit = 0;
const char NO_KEY = '\0';

void setup()
{
  lcd.init();
  lcd.backlight();
 
  lcd.print("Enter password:");
  servo.attach(SERVO_PIN);
for (int row = 0; row < 4; row++) {
    pinMode(ROW_PINS[row], OUTPUT);
    digitalWrite(ROW_PINS[row], HIGH);
  }

  for (int col = 0; col < 4; col++) {
    pinMode(COL_PINS[col], INPUT_PULLUP);
  }
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop()           
{
  char key = getKey();
  if (key != NO_KEY) 
{
    if (key == '#') 
{
      if (checkPassword()) {
        lcd.clear();
        lcd.print("Password OK!");
        unlockDoor();        
        delay(2000);
        lcd.clear(); 
        lcd.print("Locked Again");  
        servo.write(0);
        delay(2000);
        lcd.clear();  
        lcd.print("Enter password:");             
      } 
      else {
        lcd.clear();
        lcd.print("Incorrect!");
        buzz(3);
        delay(2000);
        lcd.clear();
        lcd.print("Enter password:");        
      }
      resetPassword();
    } else if (key == '*') {
      resetPassword();
      lcd.clear();
      lcd.print("Enter password:");
    } else if (isdigit(key)) {
      addDigit(key - '0');
    }
  }
}

char getKey() {
  char key = NO_KEY;
  
  for (int row = 0; row < 4; row++) {
    digitalWrite(ROW_PINS[row], LOW);
    for (int col = 0; col < 4; col++) {
      if (digitalRead(COL_PINS[col]) == LOW) {
        key = KEYS[row][col];
        while (digitalRead(COL_PINS[col]) == LOW) {
          delay(10);
        }
      }
    }
    digitalWrite(ROW_PINS[row], HIGH);
  }
  
  return key;
}

void addDigit(int digit) {
  if (currentDigit < PASSWORD_LENGTH) {
    passwordInput[currentDigit] = digit;
    currentDigit++;
    lcd.setCursor(currentDigit - 1, 1);
    lcd.print(digit);
    buzz(1);  // Optional: Provide a buzz sound when a button is pressed
    delay(200);  // Delay for button debounce
  }
}

bool checkPassword() {
  for (int i = 0; i < PASSWORD_LENGTH; i++) {
    if (passwordInput[i] != PASSWORD[i]) {
      return false;
    }
  }
  return true;
}

void resetPassword() {
  for (int i = 0; i < PASSWORD_LENGTH; i++) {
    passwordInput[i] = 0;
  }
  currentDigit = 0;
  lcd.setCursor(0, 1);
  lcd.print("                ");  // Clear the password display
}

void unlockDoor() {
  servo.write(90);  // Open the door
}

void lockDoor() {
  servo.write(0);  // Close the door
}

void buzz(int count) {
  for (int i = 0; i < count; i++) {
    digitalWrite(BUZZER_PIN, HIGH);
    delay(100);
    digitalWrite(BUZZER_PIN, LOW);
    delay(100);
  }
}