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

RTC_DS3231 rtc;

void setup() {
  Serial.begin(9600);
  Wire.begin();
  
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  if (rtc.lostPower()) {
    Serial.println("RTC lost power, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
}

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

  // Set your target time (HH:MM:SS)
  int targetHours = 9;
  int targetMinutes = 40;
  int targetSeconds = 30;

  // Calculate remaining time
  int remainingSeconds = calculateRemainingTime(now, targetHours, targetMinutes, targetSeconds);

  // Display the remaining time in HH:MM:SS format
  Serial.print("Remaining Time: ");
  printTimeRemaining(remainingSeconds);

  delay(1000); // Wait for 1 second
}

void printTime(DateTime now) {
  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.print(now.day(), DEC);
  Serial.print(" ");
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.print(now.second(), DEC);
  Serial.println();
}

void printTimeRemaining(int seconds) {
  int hours = seconds / 3600;
  int minutes = (seconds % 3600) / 60;
  int remainingSeconds = seconds % 60;

  // Print in HH:MM:SS format
  if (hours < 10) Serial.print('0');
  Serial.print(hours, DEC);
  Serial.print(':');
  if (minutes < 10) Serial.print('0');
  Serial.print(minutes, DEC);
  Serial.print(':');
  if (remainingSeconds < 10) Serial.print('0');
  Serial.println(remainingSeconds, DEC);
}

int calculateRemainingTime(DateTime now, int targetHours, int targetMinutes, int targetSeconds) {
  int remainingSeconds = 0;

  if (now.hour() < targetHours || (now.hour() == targetHours && now.minute() < targetMinutes) ||
      (now.hour() == targetHours && now.minute() == targetMinutes && now.second() < targetSeconds)) {
    remainingSeconds = ((targetHours * 3600 + targetMinutes * 60 + targetSeconds) -
                        (now.hour() * 3600 + now.minute() * 60 + now.second()));
  }

  if (remainingSeconds < 0) {
    remainingSeconds = 0;
  }

  return remainingSeconds;
}