#include <Keypad.h>

// Define the number of rows and columns of the keypad
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns

// Define the symbols on the buttons of the keypad
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

// Connect keypad ROW0, ROW1, ROW2, ROW3 to Arduino pins
byte rowPins[ROWS] = {2,3,4,5};

// Connect keypad COL0, COL1, COL2, COL3 to Arduino pins
byte colPins[COLS] = {A0,A1,A2,A3};

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

const int passwordLength = 4; // Define the desired password length
char password[passwordLength + 1]; // Array to store the password (extra space for null terminator)
char tempPassword[passwordLength + 1]; // Temporary array to store entered passwords
int keyIndex = 0; // Index to keep track of the number of key presses

enum State {CREATE_PASSWORD, CONFIRM_PASSWORD, ENTER_PASSWORD};
State currentState = CREATE_PASSWORD;

void setup() {
  Serial.begin(9600); // Start communication with the serial monitor
  memset(password, 0, sizeof(password)); // Initialize the password array with null characters
  memset(tempPassword, 0, sizeof(tempPassword)); // Initialize the tempPassword array with null characters
  Serial.println("Create a new password:");
}

void loop() {
  char key = keypad.getKey(); // Get the key pressed

  if (key) { // If a key is pressed
    if (keyIndex < passwordLength) {
      tempPassword[keyIndex] = key; // Store the key in the temporary password array
      keyIndex++; // Move to the next position

      Serial.print('*'); // Print a '*' to the serial monitor for each key press to mask the input
    }

    if (keyIndex == passwordLength) {
      tempPassword[passwordLength] = '\0'; // Null-terminate the temporary password string
      Serial.println(); // Print a newline for better readability

      switch (currentState) {
        case CREATE_PASSWORD:
          strcpy(password, tempPassword); // Copy the temporary password to the actual password
          Serial.println("Confirm your new password:");
          currentState = CONFIRM_PASSWORD;
          break;
        
        case CONFIRM_PASSWORD:
          if (strcmp(password, tempPassword) == 0) { // Compare the passwords
            Serial.println("Password confirmed!");
            Serial.println("Enter your password to unlock:");
            currentState = ENTER_PASSWORD;
          } else {
            Serial.println("Passwords do not match. Create a new password:");
            currentState = CREATE_PASSWORD;
          }
          break;
        
        case ENTER_PASSWORD:
          if (strcmp(password, tempPassword) == 0) { // Compare the passwords
            Serial.println("Password correct! Access granted.");
          } else {
            Serial.println("Incorrect password. Please try again:");
          }
          break;
      }

      // Reset the keyIndex and clear the temporary password array for the next input
      keyIndex = 0;
      memset(tempPassword, 0, sizeof(tempPassword));
    }
  }
}