#include <Keypad.h>

/* Display */
/* Keypad setup */
byte rowPins[4] = {5, 4, 3, 2};
byte colPins[4] = {A3, A2, A1, A0};

char keys[4][4] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, 4, 4);

byte pin[4] = {'1', '2', '3', '4'}; // Replace with your desired PIN

char enteredPin[4];
int pinIndex = 0;

bool checkPIN() {
  // Check if the entered PIN matches the predefined PIN
  for (int i = 0; i < 4; i++) {
    if (enteredPin[i] != pin[i]) {
      return false; // PIN mismatch
    }
  }
  return true; // PIN matches
}

void resetPIN() {
  // Reset entered PIN and index
  for (int i = 0; i < 4; i++) {
    enteredPin[i] = '\0';
  }
  pinIndex = 0;
}

void setup() {
  Serial.begin(115200);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
}

void loop() {
  char key = keypad.getKey();
  
  if (key) {
    if (key == '#') {
      // Check the entered PIN when '#' is pressed
      if (checkPIN()) {
        Serial.println("Access granted!");
        digitalWrite(8, HIGH);
        delay(200);
        digitalWrite(8, LOW);
        delay(100);
        digitalWrite(8, HIGH);
        delay(200);
        digitalWrite(8, LOW);
      } else {
        Serial.println("Incorrect PIN. Try again.");
        digitalWrite(9, HIGH);
        delay(100);
        digitalWrite(9, LOW);
        delay(100);
        digitalWrite(9, HIGH);
        delay(100);
        digitalWrite(9, LOW);
      }
      resetPIN();
    } else {
      // Update entered PIN
      enteredPin[pinIndex] = key;
      pinIndex++;
    }
  }
}