#include <Keypad.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

const int circuitBreakerPin = 13; // Pin connected to the circuit breaker relay
const int ledPin = 12;            // Pin connected to an indicator LED
const int buzzerPin = 11;          // Pin connected to a buzzer

const byte ROW_NUM    = 4; // four rows
const byte COLUMN_NUM = 4; // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte pin_rows[ROW_NUM]    = {9, 8, 7, 6}; // connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {5, 4, 3, 2}; // connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM);

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 columns and 2 rows

String defaultPassword = "1234";
String enteredPassword = "";

void setup() {
  Serial.begin(9600);
  pinMode(circuitBreakerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);

  lcd.begin(16, 2); // Initialize the LCD
  lcd.init();       // Initialize the display
  lcd.backlight();  // Turn on the backlight

  lcd.setCursor(0, 0);
  lcd.print("Welcome to");
  lcd.setCursor(0, 1);
  lcd.print("Smart System!");

  delay(3000);
  lcd.clear();

lcd.setCursor(0, 0);
  lcd.print("To change the");
  lcd.setCursor(0, 1);
  lcd.print("Password click A>");

  delay(3000);
  lcd.clear();



  lcd.setCursor(0, 0);
  lcd.print("Enter Password");
  lcd.setCursor(0, 1);
  lcd.print("----------------");
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    beep(); // Beep for every key press
    if (key == '#') {
      handleAccessRequest();
    } else if (key == 'A') {
      handlePasswordChange();
    } else {
      appendToEnteredPassword(key);
      lcd.setCursor(enteredPassword.length(), 1);
      lcd.print('*');
    }
  }
}

void handleAccessRequest() {
  if (enteredPassword == defaultPassword) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Access Granted");

    if (digitalRead(circuitBreakerPin) == HIGH) {
      lcd.setCursor(0, 1);
      lcd.print("Circuit OFF");
    } else {
      lcd.setCursor(0, 1);
      lcd.print("Circuit ON");
    }

    toggleCircuitBreaker();
    beepSuccess(); // Beep for correct password
    delay(2000);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter Password");
    lcd.setCursor(0, 1);
    lcd.print("----------------");
    clearEnteredPassword();
  } else {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Invalid Password");
    lcd.setCursor(0, 1);
    lcd.print("Try Again!");
    beepError(); // Beep for incorrect password
    delay(2000);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter Password");
    lcd.setCursor(0, 1);
    lcd.print("----------------");
    clearEnteredPassword();
  }
}

void toggleCircuitBreaker() {
  digitalWrite(circuitBreakerPin, !digitalRead(circuitBreakerPin));
  digitalWrite(ledPin, digitalRead(circuitBreakerPin));
}

void appendToEnteredPassword(char key) {
  if (enteredPassword.length() < 4) {
    enteredPassword += key;
  }
}

void clearEnteredPassword() {
  enteredPassword = "";
  lcd.setCursor(0, 1);
  lcd.print("                ");
  delay(500);
}

void handlePasswordChange() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Change Password");
  lcd.setCursor(0, 1);
  lcd.print("Enter New Pass");

  String newPassword = "";
  for (byte i = 0; i < 4; i++) {
    char newKey = keypad.getKey();
    while (!newKey) {
      newKey = keypad.getKey();
    }
    lcd.print('*');
    newPassword += newKey;
  }

  defaultPassword = newPassword;
  beepSuccess(); // Beep for password change success
  delay(500);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Password Changed");
  lcd.setCursor(0, 1);
  lcd.print("Access Granted");
  delay(2000);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Enter Password");
  lcd.setCursor(0, 1);
  lcd.print("----------------");
  clearEnteredPassword();
}

void beep() {
  tone(buzzerPin, 1000, 50); // Beep for every key press
}

void beepSuccess() {
  tone(buzzerPin, 1500, 100); // Beep for success
}

void beepError() {
  tone(buzzerPin, 500, 200); // Beep for error
}