//muhammad irsyad bin faris, muhammad khairil zakhwan bin mohd khair
//muhammad danial haiqal bin abd aziz, muhammad iqbal irfan bin amir aiman luganathan

#include <Servo.h>  // include the servo library
#include <LiquidCrystal.h>  // include the LCD library
#include <Keypad.h>  // include the Keypad library

// ultrasonic sensor pins
const int trigPin = 6;
const int echoPin = 5;

// servo motor pins
const int enaPin = 8;
const int servoPin = 9;

// buzzer pin
const int buzzerPin = 11;

// keypad pins
const int numRows = 4;
const int numCols = 3;
char keys[numRows][numCols] = {
  {'1', '2', '3'},
  {'4', '5', '6'},
  {'7', '8', '9'},
  {'*', '0', '#'}
};
byte rowPins[numRows] = {10, 8, 1, 0};
byte colPins[numCols] = {5, 4, 3};

// LCD screen pins
const int lcdRSPin = 12;
const int lcdENPin = 13;
const int lcdD4Pin = 2;
const int lcdD5Pin = 3;
const int lcdD6Pin = 4;
const int lcdD7Pin = 7;

Servo myServo;  // create a servo object
LiquidCrystal lcd(lcdRSPin, lcdENPin, lcdD4Pin, lcdD5Pin, lcdD6Pin, lcdD7Pin);  // create an LCD object
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, numRows, numCols);  // create a keypad object

const char* passcode = "1234";  // define the passcode
int passcodeIndex = 0;  // index of the passcode that the user has entered so far

void setup() {
  myServo.attach(servoPin);  // attach the servo motor to the control pin
  pinMode(trigPin, OUTPUT);  // set the trig pin as an output
  pinMode(echoPin, INPUT);   // set the echo pin as an input
  pinMode(enaPin, OUTPUT);   // set the enable pin as an output
  pinMode(buzzerPin, OUTPUT);  // set the buzzer pin as an output
  lcd.begin(16, 2);  // initialize the LCD screen with 16 columns and 2 rows

  // initialize the keypad and set the number of columns and rows
  keypad.begin(makeKeymap(keys));
}

void loop() {
  long duration, distance;
  
  // trigger the ultrasonic sensor by sending a pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // measure the duration of the pulse
  duration = pulseIn(echoPin, HIGH);
  
  // convert the duration to a distance
  distance = duration / 2 / 29.1;
  
  // if someone is within 50 cm of the sensor, start the password system
  if (distance < 50) {
    lcd.clear();  // clear the LCD screen
    lcd.setCursor(0, 0);  // set the cursor to the first column of the first row
    lcd.print("Enter passcode:");  // prompt the user to enter the passcode
    lcd.setCursor(0, 1);  // set the cursor to the first column of the second row
    lcd.print("____________");  // display an underscore for each digit of the passcode
    lcd.setCursor(0, 1);  // set the cursor to the first column of the second row
    passcodeIndex = 0;  // reset the passcode index
    
    // loop until the user enters the correct passcode or cancels the password system
    while (true) {
      // check if the user pressed a key
      char key = keypad.getKey();
      if (key) {
        // if the key is a digit, add it to the passcode
        if (key >= '0' && key <= '9') {
          lcd.print(key);  // display the digit on the LCD screen
          if (key == passcode[passcodeIndex]) {
            // if the digit is correct, move on to the next digit
            passcodeIndex++;
            if (passcodeIndex == 4) {
              // if all digits of the passcode have been entered, open the door and play a melody
              digitalWrite(enaPin, LOW);  // enable the servo motor
              myServo.write(180);  // turn the servo motor to 180 degree
              delay(3000);  // wait for 5 seconds
    myServo.write(0);  // rotate the servo back to lock the door
    lcd.clear();  // clear the LCD screen
    lcd.setCursor(0, 0);  // set the cursor to the first column of the first row
    lcd.print("WELCOME HOME");  // display "WELCOME HOME" on the LCD screen
              
              // play the melody of "You Should Probably Leave" by Chris Stapleton on the buzzer
              int tempo = 150;  // set the tempo of the melody (in ms)
              tone(buzzerPin, 262, tempo);
              delay(tempo);
              tone(buzzerPin, 262, tempo);
              delay(tempo);
              tone(buzzerPin, 392, tempo);
              delay(tempo);
              tone(buzzerPin, 392, tempo);
              delay(tempo);
              tone(buzzerPin, 440, tempo);
              delay(tempo);
              tone(buzzerPin, 440, tempo);
              delay(tempo);
              tone(buzzerPin, 392, tempo);
              delay(tempo);
              tone(buzzerPin, 349, tempo);
              delay(tempo);
              tone(buzzerPin, 349,tempo);
                            delay(tempo);
              tone(buzzerPin, 330, tempo);
              delay(tempo);
              tone(buzzerPin, 330, tempo);
              delay(tempo);
              tone(buzzerPin, 294, tempo);
              delay(tempo);
              tone(buzzerPin, 294, tempo);
              delay(tempo);
              tone(buzzerPin, 262, tempo);
              delay(tempo);
              tone(buzzerPin, 262, tempo);
              delay(tempo);
              
              break;  // exit the loop
              delay(100);
            }
          } else {
            // if the digit is incorrect, reset the passcode index
            passcodeIndex = 0;
            lcd.setCursor(0, 1);  // set the cursor to the first column of the second row
            lcd.print("____________");  // display an underscore for each digit of the passcode
            lcd.setCursor(0, 1);  // set the cursor to the first column of the second row
          }
        } else if (key == '*') {
          // if the key is '*', cancel the password system and close the door
          digitalWrite(enaPin, LOW);  // enable the servo motor
          myServo.write(0);  // turn the servo motor to 0 degrees
          delay(1000);  // wait for the door to close
          digitalWrite(enaPin, HIGH);  // disable the servo motor
          break;  // exit the loop
        }
      }
    }
  }
}