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

const int ROW_NUM    = 4; // jumlah baris keypad
const int COLUMN_NUM = 4; // jumlah kolom keypad

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3','P1'},
  {'4','5','6','P2'},
  {'7','8','9','P3'},
  {'*','0','#','P4'}
};

byte pin_rows[ROW_NUM]    = {9, 8, 7, 6}; // koneksi pin baris keypad
byte pin_column[COLUMN_NUM] = {5, 4, 3, 2}; // koneksi pin kolom keypad

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM);
LiquidCrystal_I2C lcd(0x27, 16, 2); // Alamat I2C untuk LCD

float hargaPerLiter = 10000; // Harga per liter bahan bakar
float liter = 0;
float totalHarga = 0;

void setup() {
  lcd.begin(16,2);
  lcd.print("Liter: 0.00");
  lcd.setCursor(0,1);
  lcd.print("Harga: 0.00");
  lcd.backlight();
}

void loop() {
  char key = keypad.getKey();
  
  if (key) {
    if (key == '#') {
      // Tombol # untuk mereset counter
      liter = 0;
      totalHarga = 0;
    } else if (key == '*') {
      // Tombol * untuk mengurangkan satu liter
      liter -= 1;
      if (liter < 0) {
        liter = 0;
      }
      totalHarga = liter * hargaPerLiter;
    } else if (key == 'P1' || key == 'P2' || key == 'P3' || key == 'P4') {
      // Pembelian paket
      int paketSize = key - '0'; // Mendapatkan jumlah liter dari karakter terakhir
      liter += paketSize;
      totalHarga = liter * hargaPerLiter;
    } else if (key >= '0' && key <= '9') {
    // Menambah liter dan menghitung total harga
    liter = liter * 10 + (key - '0');
    totalHarga = liter * hargaPerLiter;
    }

    // Update tampilan LCD
    lcd.setCursor(7, 0);
    lcd.print(liter, 2);
    lcd.setCursor(7, 1);
    lcd.print(totalHarga, 2);
  }
}