//Date and time functions using a DS3231 RTC connected via I2C and Wire lib
#include "RTClib.h"

#define TIME_HEADER  "T"
#define TIME_UNIX    "U"

RTC_DS3231 rtc;

char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

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

  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    while (1) delay(10);
  }
  Serial.println("Set the RTC by sending \"T\"year, month, day, hour, minute, second");
  Serial.println("For example T2025,3,12,15,25,0  when your pc system clock hits the time you");
  Serial.println("hit [Return]");
  Serial.println("If you are off by a second or so, have another go!!!");
  Serial.println("////////Get your local time @ https://time.is");
  /*
    if (rtc.lostPower()) {
      Serial.println("RTC lost power, let's set the time!");
      // When time needs to be set on a new device, or after a power loss, the
      // following line sets the RTC to the date & time this sketch was compiled
      //rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
      // This line sets the RTC with an explicit date & time, for example to set
      // January 21, 2014 at 3am you would call:
      // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
    }

    // When time needs to be re-set on a previously configured device, the
    // following line sets the RTC to the date & time this sketch was compiled
    // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    // This line sets the RTC with an explicit date & time, for example to set
    // January 21, 2014 at 3am you would call:
    // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
  */
}

char timeStr[10] = {0};
char dateStr[12] = {0};
uint32_t lastTime = 0;
bool Set = false;

void printDateTime() {

  DateTime now = rtc.now();
  Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
  sprintf(dateStr, " %d/%d/%d", now.day(), now.month(), now.year());
  sprintf(timeStr, " %02d:%02d:%02d", now.hour(), now.minute(), now.second());
  Serial.print(dateStr);
  Serial.println(timeStr);
  Serial.println(now.unixtime());
  Serial.print("Temperature: ");
  Serial.print(rtc.getTemperature());
  Serial.println("°C\n");

}

void loop () {

  if (Set) {
    if (millis() - lastTime > 1000) {
      lastTime = millis();
      printDateTime();
    }
  }

  ////////Set the RTC by sending "T"year, month, day, hour, minute, second//////
  ////////For example T2025,3,12,15,25,0  when your pc system clock hits the time you
  ////////hit [Return]
  ////////If you are off by a second or so, have another go!!!

  ////////Get your local time @ https://time.is

  while (Serial.available()) {

    char c = Serial.read();
    delay(10);

    if (c == 'T') {
      uint16_t yr = Serial.parseInt();
      uint8_t mo = Serial.parseInt();
      uint8_t dy = Serial.parseInt();
      uint8_t hr = Serial.parseInt();
      uint8_t mn = Serial.parseInt();
      uint8_t sc = Serial.parseInt();
      rtc.adjust(DateTime(yr, mo, dy, hr, mn, sc));
      Serial.println("RTC was Set at...");
      printDateTime();
      Set = true;
    }
    //Get an Epoch converter (Google Chrome Extension) you can input a future time
    // and send the resulting stamp with a "U" prefix, for example U1741809988
    // copy/paste the above to try
    
    else if (c == 'U') {
      uint32_t Unix = Serial.parseInt();
      rtc.adjust(DateTime(Unix));
      Serial.println("RTC was Set at...");
      printDateTime();
      Set = true;
    }
  }
}