#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <RTClib.h>

#define SCREEN_WIDTH 128 // OLED display width,  in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
RTC_DS1307 rtc;

String date;
String time;

void setup() {
  Serial.begin(9600);
  
  // initialize OLED display with address 0x3C for 128x64
  if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    while (true);
  }
  
  delay(1000);         // wait for initializing
  oled.clearDisplay(); // clear display
  oled.setTextSize(2);          // text size
  oled.setTextColor(WHITE);     // text color
  
  // SETUP RTC MODULE
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    while (true);
  }
  
  // automatically sets the RTC to the date & time on PC this sketch was compiled
  // rtc.adjust(DateTime(2024, 11, 20, 9, 3, 0)); // Format: yyyy, mm, dd, hh, mm, ss
  rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  time.reserve(10); // to avoid fragmenting memory when using String
}

void loop() {
  int16_t x1;
  int16_t y1;
  uint16_t width;
  uint16_t height;
  
  // Clear the OLED display
  oled.fillScreen(BLACK);
  
  DateTime now = rtc.now();
  
  // Format tanggal dengan leading zero
  date = "";
  // Tambahkan leading zero untuk hari
  if (now.day() < 10) date += "0";
  date += now.day();
  date += "/";
  // Tambahkan leading zero untuk bulan
  if (now.month() < 10) date += "0";
  date += now.month();
  date += "/";
  date += now.year();
  
  // Format waktu dengan leading zero
  time = "";
  // Tambahkan leading zero untuk jam
  if (now.hour() < 10) time += "0";
  time += now.hour();
  time += ':';
  // Tambahkan leading zero untuk menit
  if (now.minute() < 10) time += "0";
  time += now.minute();
  time += ':';
  // Tambahkan leading zero untuk detik
  if (now.second() < 10) time += "0";
  time += now.second();
  
  // Print the date and time to the OLED display
  oled.getTextBounds(date, 0, 0, &x1, &y1, &width, &height);
  oled.setCursor((SCREEN_WIDTH - width) / 2, (SCREEN_HEIGHT + height) / 2);
  oled.println(date);
  
  oled.getTextBounds(time, 0, 0, &x1, &y1, &width, &height);
  oled.setCursor((SCREEN_WIDTH - width) / 2, (SCREEN_HEIGHT - 3*height) / 2);
  oled.print(time);
  
  oled.display();
}