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

// set address sesuai address i2c-nya, jumlah baris dan kolom
LiquidCrystal_I2C lcd(0x27,16,2);

// mendefinisikan pin tombol
#define BT_MENU 0
#define BT_LIST_MENU 4

// Varibel yang bisa berubah
int lastState_bt_menu = HIGH;
int lastState_bt_list_menu = HIGH;
int currentState_bt_menu;
int currentState_bt_list_menu;

// List data yang akan ditampilkan
int count_menu, count_makanan, count_minuman, count_snack = 0;
String Menu[] = {"Makanan", "Minuman", "Snack"};
String Makanan[] = {"Nasi Goreng", "Nasi Soto", "Ayam Goreng", "Lalapan Lele"};
String Minuman[] = {"Pop Ice", "Teh Manis", "Es Campur", "Es Kelapa Muda"};
String Snack[] = {"Kentang Goreng", "Gorengan", "Cilot", "Roti Bakar"};

String cls = " ---- MENU ----";
String pilihan_menu = "Silahkan memesan";
String pilihan_item = cls;

void setup() {
  Serial.begin(115200);

  // mendefinisikan tombol sebagai input pullup
  pinMode(BT_MENU, INPUT_PULLUP);
  pinMode(BT_LIST_MENU, INPUT_PULLUP);

  // Memulai dan membersihkan lcd serta menyalakan lampu backlight
  lcd.init();
  lcd.clear();
  lcd.backlight();
  
  lcd.setCursor(3,0);
  lcd.print("Welcome To");
  lcd.setCursor(1,1);
  lcd.print("Kantin POLIJE");
  delay(2000);
  
  lcd.clear();
  delay(200);
}

void loop() {
  // membaca nilai button dari user
  currentState_bt_menu = digitalRead(BT_MENU);
  currentState_bt_list_menu = digitalRead(BT_LIST_MENU);

  // tombol Pilihan Menu Ditekan
  if(lastState_bt_menu == HIGH && currentState_bt_menu == LOW) {
    lcd.clear();
    delay(100);
    Serial.println(Menu[count_menu]); 
    pilihan_menu = Menu[count_menu];
    pilihan_item = cls;
    count_menu++;
    if(count_menu==3) {
      count_menu = 0;
    }
  }
  
  // tombol List Menu Ditekan
  if(lastState_bt_list_menu == HIGH && currentState_bt_list_menu == LOW) {
    if (pilihan_menu == "Makanan") {
      lcd.clear();
      delay(100);
      Serial.println(Makanan[count_makanan]); 
      pilihan_item = Makanan[count_makanan];
      count_makanan++;
      if (count_makanan == 4) { count_makanan = 0; }
    }
    if (pilihan_menu == "Minuman") {
      lcd.clear();
      delay(100);
      Serial.println(Minuman[count_minuman]); 
      pilihan_item = Minuman[count_minuman];
      count_minuman++;
      if (count_minuman == 4) { count_minuman = 0; }
    }
    if (pilihan_menu == "Snack") {
      lcd.clear();
      delay(100);
      Serial.println(Snack[count_snack]); 
      pilihan_item = Snack[count_snack];
      count_snack++;
      if (count_snack == 4) { count_snack = 0; }
    }
  }

  // Mengubah data lastState
  lastState_bt_menu = currentState_bt_menu;
  lastState_bt_list_menu = currentState_bt_list_menu;

  // Tampilkan data pada lcd
  lcd.setCursor(0,0);
  lcd.print(pilihan_menu);
  lcd.setCursor(0,1);
  lcd.print(pilihan_item);
}