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

Servo myservo;
int pos = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);

const byte ROWS = 4;
const byte COLS = 4;

char Keys[ROWS][COLS] =
{
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPin[ROWS] = {2, 3, 4, 5};
byte colsPin[COLS] = {6, 7, 8, 9};

Keypad customKeypad = Keypad(makeKeymap(Keys), rowPin, colsPin, ROWS, COLS);

#define Password_Length 7 
char Data[Password_Length];
char Master[Password_Length] = "452333";
byte data_count = 0;
char customKey;

bool door = true;
int wrongPasswordCount = 0;

const int buzzerPin = 11;

bool changePasswordMode = false;
bool verifyOldPassword = true;
char NewPassword[Password_Length];
byte newPasswordCount = 0;

void setup() {
  lcd.init();
  lcd.backlight();
  myservo.attach(10);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  if (changePasswordMode) {
    changePassword();
  } else if (door == 0) {
    customKey = customKeypad.getKey();
    if (customKey == '#') {
      lcd.clear();
      ServoClose();
      lcd.print("  Door is close");
      delay(3000);
      door = 1;
    }
  } else {
    Open();
  }
}

void Open() {
  lcd.setCursor(0, 0);
  lcd.print(" Enter Password");

  customKey = customKeypad.getKey();
  if (customKey) {
    Data[data_count] = customKey;
    lcd.setCursor(data_count, 1);
    lcd.print(Data[data_count]);
    data_count++;
  }

  if (data_count == Password_Length - 1) {
    if (!strcmp(Data, Master)) {
      lcd.clear();
      ServoOpen();
      lcd.print("  Door is Open");
      door = 0;
      wrongPasswordCount = 0;
    } else {
      wrongPasswordCount++;
      lcd.clear();
      lcd.print("  Wrong Password");
      delay(1000);

      if (wrongPasswordCount >= 3) {
        soundBuzzer();
        wrongPasswordCount = 0;
      }
    }
    clearData();
  }

  if (customKey == '*') {
    lcd.clear();
    lcd.print("Old Password");
    delay(1000);
    clearData();
    changePasswordMode = true;
    verifyOldPassword = true;
  }
}

void changePassword() {
  if (verifyOldPassword) {
    lcd.setCursor(0, 0);
    lcd.print("Old Password");

    customKey = customKeypad.getKey();
    if (customKey) {
      Data[data_count] = customKey;
      lcd.setCursor(data_count, 1);
      lcd.print(Data[data_count]);
      data_count++;
    }

    if (data_count == Password_Length - 1) {
      if (!strcmp(Data, Master)) {
        lcd.clear();
        lcd.print("New Password");
        delay(1000);
        clearData();
        verifyOldPassword = false;
      } else {
        lcd.clear();
        lcd.print("Wrong Password");
        delay(2000);
        clearData();
        changePasswordMode = false;
      }
    }
  } else {
    lcd.setCursor(0, 0);
    lcd.print(" New Password");

    customKey = customKeypad.getKey();
    if (customKey) {
      NewPassword[newPasswordCount] = customKey;
      lcd.setCursor(newPasswordCount, 1);
      lcd.print(NewPassword[newPasswordCount]);
      newPasswordCount++;
    }

    if (newPasswordCount == Password_Length - 1) {
      strcpy(Master, NewPassword);
      lcd.clear();
      lcd.print("Password Changed");
      delay(2000);
      clearData();
      newPasswordCount = 0;
      changePasswordMode = false;
    }
  }
}

void clearData() {
  while (data_count != 0) {
    Data[data_count--] = 0;
  }
}

void ServoOpen() {
  for (pos = 180; pos >= 0; pos -= 5) {
    myservo.write(pos);
    delay(15);
  }
}

void ServoClose() {
  for (pos = 0; pos <= 180; pos += 5) {
    myservo.write(pos);
    delay(15);
  }
}

void soundBuzzer() {
  digitalWrite(buzzerPin, HIGH);
  delay(5000);
  digitalWrite(buzzerPin, LOW);
}