#include <Keypad.h>
#include <EEPROM.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Buzzer.h> // Include the Tone library for buzzer

// Define constants for better readability and maintainability
const int PASSWORD_LENGTH = 5;
const int BUZZER_PIN = 10; // Define the buzzer pin
const int BUZZER_FREQUENCY = 1500; // Define the buzzer frequency
const int MAX_WRONG_ATTEMPTS = 5; // Maximum allowed wrong attempts before locking
const int LOCK_DURATION = 30000; // Lock duration in milliseconds (30 seconds)

// Initialize LCD object
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Declare variables
char password[PASSWORD_LENGTH];
char initial_password[PASSWORD_LENGTH], new_password[PASSWORD_LENGTH];
int vcc = 11;
int i = 0;
int relay_pin = 11;
char key_pressed = 0;
const byte rows = 4;
const byte columns = 4;
char hexaKeys[rows][columns] = {
    {'1', '2', '3', 'A'},
        {'4', '5', '6', 'B'},
            {'7', '8', '9', 'C'},
                {'*', '0', '#', 'D'}};
                byte row_pins[rows] = {2, 3, 4, 5};
                byte column_pins[columns] = {6, 7, 8, 9};
                Keypad keypad_key = Keypad(makeKeymap(hexaKeys), row_pins, column_pins, rows, columns);
                int wrong_attempts = 0; // Counter for wrong attempts
                unsigned long lock_start_time = 0; // Timestamp to track lock start time
                bool device_locked = false; // Flag to indicate device lock state

                // Setup function
                void setup()
                {
                    // Initialize LCD
                        lcd.begin(16, 2);
                            lcd.backlight();

                                // Set pin modes
                                    pinMode(relay_pin, OUTPUT);
                                        pinMode(vcc, OUTPUT);
                                            pinMode(BUZZER_PIN, OUTPUT); // Set buzzer pin as output

                                                // Display startup message
                                                    lcd.print("    WELCOME");
                                                        lcd.setCursor(0, 1); 
                                                            delay(3000);
                                                                lcd.clear();

                                                                    // Prompt user to enter password
                                                                        lcd.print("Enter Password:");
                                                                            lcd.setCursor(0, 1);
                                                                                initialpassword();
                                                                                }

                                                                                // Main loop function
                                                                                void loop()
                                                                                {
                                                                                    digitalWrite(relay_pin, HIGH);

                                                                                        // Check if '#' key is pressed to initiate password change
                                                                                            key_pressed = keypad_key.getKey();
                                                                                                if (key_pressed == '#' && !device_locked)
                                                                                                        change();

                                                                                                            // Check for keypad input
                                                                                                                if (key_pressed && !device_locked)
                                                                                                                    {
                                                                                                                            // Mask the password input with '*'
                                                                                                                                    password[i++] = key_pressed;
                                                                                                                                            lcd.print('*');
                                                                                                                                                }

                                                                                                                                                    // Check if password length is reached and device not locked
                                                                                                                                                        if (i == PASSWORD_LENGTH && !device_locked)
                                                                                                                                                            {
                                                                                                                                                                    delay(200);

                                                                                                                                                                            // Read initial password from EEPROM
                                                                                                                                                                                    for (int j = 0; j < PASSWORD_LENGTH; j++)
                                                                                                                                                                                                initial_password[j] = EEPROM.read(j);

                                                                                                                                                                                                        // Check if entered password matches initial password
                                                                                                                                                                                                                if (!(strncmp(password, initial_password, PASSWORD_LENGTH)))
                                                                                                                                                                                                                        {
                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                lcd.print("Pass Accepted");
                                                                                                                                                                                                                                                            digitalWrite(relay_pin, LOW);
                                                                                                                                                                                                                                                                        buzzOnce(); // Buzz once for correct password
                                                                                                                                                                                                                                                                                    delay(2000);
                                                                                                                                                                                                                                                                                                lcd.setCursor(0, 0);

                                                                                                                                                                                                                                                                                                            lcd.clear();
                                                                                                                                                                                                                                                                                                                        lcd.print("Enter Password:");
                                                                                                                                                                                                                                                                                                                                    lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                i = 0;
                                                                                                                                                                                                                                                                                                                                                            wrong_attempts = 0; // Reset wrong attempts counter
                                                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                                                            else
                                                                                                                                                                                                                                                                                                                                                                                    {
                                                                                                                                                                                                                                                                                                                                                                                                // Increment wrong attempts counter
                                                                                                                                                                                                                                                                                                                                                                                                            wrong_attempts++;

                                                                                                                                                                                                                                                                                                                                                                                                                        // Check if maximum wrong attempts reached
                                                                                                                                                                                                                                                                                                                                                                                                                                    if (wrong_attempts >= MAX_WRONG_ATTEMPTS)
                                                                                                                                                                                                                                                                                                                                                                                                                                                {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                device_locked = true;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lock_start_time = millis(); // Record lock start time
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        digitalWrite(relay_pin, HIGH);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.print("Wrong Password");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            buzzEscapeAlarm(); // Buzz like an escape alarm for wrong password
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.setCursor(0, 0);

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.print("Enter Password:");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        i = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        // Check if device is locked
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            if (device_locked)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        // Check if lock duration has passed
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                if (millis() - lock_start_time >= LOCK_DURATION)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    device_locked = false; // Unlock the device
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.print("Device Unlocked");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        delay(2000);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.print("Enter Password:");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            else
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.print("Device in Lock");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.print("Wait for 30 secs");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                delay(500);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            // Function to change password
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            void change()
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                int j = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.print("Current Password");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                while (j < PASSWORD_LENGTH)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            char key = keypad_key.getKey();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    if (key)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        new_password[j++] = key;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.print('*'); // Mask the password input with '*'
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    key = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            delay(500);

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                // Check if entered current password matches initial password
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    if ((strncmp(new_password, initial_password, PASSWORD_LENGTH)))
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.print("Wrong Password");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.print("Try Again");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                delay(1000);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        else
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    j = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.print("New Password:");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.setCursor(0, 1);

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    while (j < PASSWORD_LENGTH)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        char key = keypad_key.getKey();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    if (key)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                initial_password[j] = key;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.print('*'); // Mask the password input with '*'
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                EEPROM.write(j, key);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                j++;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.print("Pass Changed");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    delay(1000);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                lcd.print("Enter Password:");
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.setCursor(0, 1);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        key_pressed = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        // Function to initialize password from EEPROM
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        void initialpassword()
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            for (int j = 0; j < PASSWORD_LENGTH; j++)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    EEPROM.write(j, j + 49);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        for (int j = 0; j < PASSWORD_LENGTH; j++)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                initial_password[j] = EEPROM.read(j);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                // Function to make the buzzer sound once
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                void buzzOnce()
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    tone(BUZZER_PIN, 1000, 100); // Buzz at 1000 Hz for 100 ms
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    // Function to make the buzzer sound like an escape alarm
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    void buzzEscapeAlarm()
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        for (int i = 0; i < 5; i++)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    tone(BUZZER_PIN, BUZZER_FREQUENCY, 200); // Buzz at specified frequency for 200 ms
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            delay(300); // Wait for 300 ms between each buzz
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }