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

Servo servoMotor;

#define ROWS 4
#define COLS 5

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

byte rowPins[ROWS] = {9, 8, 7, 6};
byte colPins[COLS] = {5, 4, 3, 2};

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

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  servoMotor.attach(10); // pin servo
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.backlight();
}

void loop() {
  // step 1: setel static key
  // CATATAN: key hanya bisa dengan biner 00 atau 01, sebab keterbatasan keyp
  servoMotor.write(90);
  int staticKey[2][1] = {{0},{1}}; // 01 dalam biner

  // step 2: input pin
  plaintext();

  char pin[5]; // pin 4 digit + null terminator utk mengakhiri string array
  int index = 0;
  while(index < 4) {
    char key = keypad.getKey();
    if (key) {
      pin[index++] = key;
      lcd.setCursor(index-1,1);
      lcd.print(key);
    }
  }
  pin[4] = '0'; // null terminator

  // step 3: konversi pin ke biner
  int pinBinary[4][4];
  for (int i = 0; i < 4; i++) {
    int digit = pin[i] - '0'; // konversi char ke int agar bisa dihitung biner
    for (int j = 3; j >= 0; j--) {
      pinBinary[i][j] = digit % 2;
      digit /= 2;
    }
  }

  // step 4: enkripsi pinBinary dengan gerbang NAND
  int jerry[2][4], tono[4][4];

  // enkripsi NAND dari biner (digit 1 dgn dgn 2), dan (digit 3 dgn digit 4)
  for (int i = 0; i < 4; i++) {
    jerry[0][i] = !(pinBinary[0][i] && pinBinary[1][i]);
    jerry[1][i] = !(pinBinary[2][i] && pinBinary[3][i]);
    tono[i][2] = jerry[1][i];
  }

  // step 5: memasukkan data ke jerry dan tono (penyimpanan memory)

  // enkripsi NAND dari jerry antara baris 1 dgn baris 2 (pasangan digit yang sama)
  for (int i = 0; i < 4; i++) {
    tono[i][3] = !(jerry[0][i] && jerry[1][i]); // output disimpan ke tono
  }

  // menyimpan key ke tono (key digit 1 ke tono kolom 1, key digit 2 ke tono)
  for (int i = 0; i < 4; i++) {
    for (int j = 0; j < 4; j++) {
      tono[j][i] = staticKey[i][0];
    }
  }

  // step 6: konversi tono ke kode ASCII
  char suzu[5]; // 4-digit pin + null terminator
  for (int i = 0; i < 4; i++) {
    int ascii = 0;
    for (int i =  0; < 4; j++) {
      ascii += tono[i][j] * pow(2, 3, - j);
    }
    suzu[i] = ascii + '0'; // Convert int to char
  }
  suzu[4] = '\0'; // Null terminator

  // step 7: menampilkan suzu (kode OTP)
  OTP();
  lcd.setCursor(0,1);
  lcd.print(suzu);
  delay(3000);

  // validasi input pin
  masukPin();
  char input[5];
  index = 0;
  bool correctPin = false;
  while(index < 4) {
    char key = keypad.getKey();
    if (key) {
      input[index++] = key;
      lcd.setCursor(index-1,1);
      lcd.print("*");
    }
  }
  input[4] = '\0'; // null terminator

  if (strcmp(input, suzu) == 0) {
    correctPin = true;
  }

  if (correctPin) {
    bukaGerbang();
  } else {
    salahPin();

    // menghitung percobaan yang salah
    int incorrectAttempts = 1;
    while (incorretAttempts < 3) {
      // mengecek input apakah salah
      index = 0;
      while(index < 4) {
        char key = keypad.getKey();
        if (key) {
          input[index++] = key;
          lcd.setCursor(index-1,1);
          lcd.print("*");
        }
      }
      input[4] = '\0'; // null terminator

      if (strcmp(input, suzu) != 0) {
        incorrectAttempts++;
        salahPin();
      } else {
        correctPin = true;
        bukaGerbang();
        break;
      }
    }

    // jika pin input dimasukkan salah sebanyak 3 kali
    if (incorrectAttempts == 3 && ! corretPin) {
      brankasTerkunci();
    }
  }
}


// semua tampilan LCD
void plaintext() {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Masukkan kunci");
}
void masukPin() {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Masukkan PIN");
}
void OTP() {
   lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Berikut PIN OTP");
}
void bukaGerbang() {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Akses Diterima!");
  servoMotor.write(0); // servo terbuka
  delay(5000);
}
void salahPin() {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Salah, ulangi!");
}
void brankasTerkunci() {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Brankas Terkunci");
  tone(11, 1000); // suara buzzer
  delay(2000);
  noTone(11);
}