#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 time;
String date;

void setup() {
  Serial.begin(9600);

  if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    while (true);
  }

  delay(2000);
  oled.clearDisplay();

  oled.setTextSize(1);
  oled.setTextColor(WHITE);
  oled.setCursor(0, 10);

  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    while (true);
  }

  // rtc.adjust(DateTime(F(_DATE_), F(_TIME_))); // Comment or remove this line
  time.reserve(10);
  date.reserve(12);
}

void loop() {
  DateTime now = rtc.now();

  if (now.isValid()) {
    // Adjust for Philippines time zone (UTC+8)
    now = now + TimeSpan(8, 0, 0, 0);

    time = "";
    time += now.hour();
    time += ':';
    time += now.minute() < 10 ? "0" : "";
    time += now.minute();
    time += ':';
    time += now.second();

    date = "";
    date += now.day();
    date += '/';
    date += now.month();
    date += '/';
    date += now.year();

    oled.clearDisplay();

    oled.setTextSize(1);
    oled.setCursor(0, 0);
    oled.println("Time");

    oledDisplayCenter(time, 20);

    oled.setTextSize(1);
    oled.setCursor(0, 40);
    oled.println("Date");

    oledDisplayCenter(date, 50);

    oled.display();
  }

  delay(1000);
}

void oledDisplayCenter(String text, int yPosition) {
  int16_t x1;
  int16_t y1;
  uint16_t width;
  uint16_t height;

  oled.getTextBounds(text, 0, 0, &x1, &y1, &width, &height);

  oled.setCursor((SCREEN_WIDTH - width) / 2, yPosition);
  oled.println(text);
}