#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#define I2C_ADDR 0x27 // Change to your address if needed

LiquidCrystal_I2C lcd(I2C_ADDR, 20, 4); // Initialize LCD for 20x4

// Keypad configuration
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'} // Using '#' as Enter key and '*' as Backspace key
};

// Pin assignments
byte rowPins[ROWS] = {14, 27, 26, 25}; // Adjust these pins as per your ESP32 model
byte colPins[COLS] = {33, 32, 18, 19}; // Adjust these pins as per your ESP32 model

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

// Security code
const char* password = "1234"; // Your defined security code
char enteredPassword[5]; // Array to store the entered password
int buzzerPin = 23; // Pin for the buzzer
int redLedPin = 16; // Pin for the red LED

void setup() {
  Serial.begin(9600);
  pinMode(buzzerPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  digitalWrite(redLedPin, LOW); // Ensure LED is off at the start
    lcd.begin();         // Initialize the LCD 
    lcd.backlight();     // Turn on the backlight
    lcd.setCursor(0, 0); // Set cursor to column 0, row 0
    lcd.print("Enter the code"); // Print message on LCD
}

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

  if (key) {
    Serial.println(key); // Display the pressed key for debugging
    
    // If the enter key '#' is pressed
    if (key == '#') {
      enteredPassword[4] = '\0'; // Null-terminate the string
      if (strcmp(enteredPassword, password) == 0) {
        // If the password is correct
        digitalWrite(redLedPin, LOW); // Turn off the LED
        noTone(buzzerPin); // Turn off the buzzer
        Serial.println("Correct Password!"); // Successful message
        delay(2000); // Optional delay before reset
        lcd.clear(); // Clear the LCD
        lcd.print("Access Granted"); // Show message
      } else {
        // If the password is incorrect
        triggerAlarm(); // Call the alarm function
        Serial.println("Incorrect Password!"); // Failure message
      lcd.clear(); // Clear the LCD
      lcd.print("Access Denied"); // Show message
      }
      // Reset the password entry
      memset(enteredPassword, 0, sizeof(enteredPassword)); // Clear the entered password
      return; // Exit the loop
    } 
    // If the backspace key '*' is pressed
    else if (key == '*') {
      for (int i = 3; i >= 0; i--) {
        if (enteredPassword[i] != 0) { // Find the last entered character
          enteredPassword[i] = 0; // Clear the last character
          break; // Exit the loop after removing one character
        }
      }
    } else {
      // Add the entered key to the enteredPassword array
      for (int i = 0; i < 4; i++) {
        if (enteredPassword[i] == 0) { // Find the first empty spot
          enteredPassword[i] = key; // Add the key to the enteredPassword
          break;
        }
      }
    }
  }
}

// Function to handle incorrect password entry
void triggerAlarm() {
  while (true) {
    digitalWrite(redLedPin, HIGH); // Turn on the red LED
    tone(buzzerPin, 1000); // Start buzzer sound (1000 Hz)
    delay(300); // Duration buzzer and LED ON
    digitalWrite(redLedPin, LOW); // Turn off the red LED
    noTone(buzzerPin); // Stop buzzer sound
    delay(300); // Duration buzzer and LED OFF
    Serial.println("Incorrect Password!");
    // Check for keypad input to reset alarm
    char key = keypad.getKey();
    if (key == '*') { // Press '*' to reset the alarm
      digitalWrite(redLedPin, LOW); // Turn off the LED
      noTone(buzzerPin); // Turn off the buzzer
      break; // Exit the alarm routine
    }
  }
}