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

// ================= PIN =================
#define LED_PIN 2
#define BUZZER_PIN 4
#define SERVO_PIN 18

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

// ================= SERVO =================
Servo myServo;

// ================= KEYPAD =================
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 rowPins[ROWS] = {13, 12, 14, 27};
byte colPins[COLS] = {26, 25, 33, 32};

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

// ================= PASSWORD =================
String correctPassword = "1234";
String inputPassword = "";

// ================= SETUP =================
void setup() {
  Serial.begin(115200);

  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  myServo.attach(SERVO_PIN);
  myServo.write(0); // posisi terkunci

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("SMART LOCK");
  lcd.setCursor(0, 1);
  lcd.print("Enter PIN:");

  digitalWrite(LED_PIN, HIGH); // LOCK = LED ON
}

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

  if (key) {
    Serial.println(key);

    if (key == '#') {
      checkPassword();
    } 
    else if (key == '*') {
      resetInput();
    } 
    else {
      inputPassword += key;

      lcd.setCursor(inputPassword.length() - 1, 1);
      lcd.print("*");
    }
  }
}

// ================= FUNCTION =================
void checkPassword() {
  lcd.clear();

  if (inputPassword == correctPassword) {
    lcd.print("ACCESS GRANTED");
    unlockDoor();
  } else {
    lcd.print("WRONG PASSWORD");
    alarm();
  }

  delay(2000);
  resetInput();
}

void resetInput() {
  inputPassword = "";
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Enter PIN:");
}

void unlockDoor() {
  digitalWrite(LED_PIN, LOW); // LED OFF = unlock

  myServo.write(90); // buka
  delay(3000);

  myServo.write(0); // kunci lagi
  digitalWrite(LED_PIN, HIGH);
}

void alarm() {
  for (int i = 0; i < 3; i++) {
    digitalWrite(BUZZER_PIN, HIGH);
    delay(200);
    digitalWrite(BUZZER_PIN, LOW);
    delay(200);
  }
}