#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Keypad.h>

// Define the OLED display
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Define the keypad
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 the correct password
const char password[] = "1234";

void setup() {
  // Initialize the display
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Enter password:");
  display.display();
}

void loop() {
  static char enteredPassword[5] = "";
  static byte passwordIndex = 0;

  // Check if a key is pressed
  char key = keypad.getKey();
  if (key) {
    // Check if the entered password is correct
    if (key == '#') {
      if (strcmp(enteredPassword, password) == 0) {
        // Correct password
        display.clearDisplay();
        display.setCursor(0, 0);
        display.println("Password correct!");
        display.display();
        delay(2000);
        // Reset the entered password
        memset(enteredPassword, 0, sizeof(enteredPassword));
        passwordIndex = 0;
      } else {
        // Incorrect password
        display.clearDisplay();
        display.setCursor(0, 0);
        display.println("Password incorrect!");
        display.display();
        delay(2000);
        // Reset the entered password
        memset(enteredPassword, 0, sizeof(enteredPassword));
        passwordIndex = 0;
      }
    } else if (key == '*') {
      // Clear the entered password
      memset(enteredPassword, 0, sizeof(enteredPassword));
      passwordIndex = 0;
    } else {
      // Append the entered digit to the password
      enteredPassword[passwordIndex] = key;
      passwordIndex++;
      // Display the entered password
      display.clearDisplay();
      display.setCursor(0, 0);
      display.print("Enter password:");
      display.setCursor(0, 20);
      display.println(enteredPassword);
      display.display();
    }
  }
}