#include <Arduino.h>
#include <Keypad.h>

// Define keypad layout
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] = { A5, A4 , A3, A2 }; // Example row pins
byte colPins[COLS] = { A1, A0, D7, D8 };   // Example column pins

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

// LED pin
const int ledPin = D4; // GPIO 4

// Password to operate the LED
const char* password = "22138059"; // Replace with your registration number

void setup() {
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
}

void loop() {
  static char inputpad[20]; // Buffer to store entered password
  static int inputpadIndex = 0;

  char key = keypad.getKey();
  if (key != NO_KEY) {
    Serial.println(key);
    inputpad[inputpadIndex++] = key;
    inputpad[inputpadIndex] = '\0'; // Null-terminate the string

    // Check if the entered password matches
    if (strcmp(inputpad, password) == 0) {
      digitalWrite(ledPin, HIGH); // Turn on LED
      delay(1000); // Delay for 1 second
      digitalWrite(ledPin, LOW); // Turn off LED
      inputpadIndex = 0; // Reset buffer
    }
    // Clear buffer if wrong password
    else if (inputpadIndex >= strlen(password)) {
      inputpadIndex = 0; // Reset buffer
    }
  }
}