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

RTC_DS3231 rtc;
LiquidCrystal_I2C lcd(0x27, 16, 2);

const char daysOfWeek[][4] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
const char months[][4] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

const int SELECT_BUTTON = 2;  // Replace with the actual pin numbers
const int INCREMENT_BUTTON = 3;
const int DECREMENT_BUTTON = 4;

int selectedField = 0;  // 0: Hour, 1: Minute, 2: Day, 3: Month, 4: Year

//===============som mod ======
String modeDisplay = "  (A)";
//===============som mod ======

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

  lcd.begin(16, 2); lcd.backlight();
  pinMode(SELECT_BUTTON, INPUT_PULLUP);
  pinMode(INCREMENT_BUTTON, INPUT_PULLUP);
  pinMode(DECREMENT_BUTTON, INPUT_PULLUP);
}

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

  if (digitalRead(SELECT_BUTTON) == LOW) {
    adjustTime(now);
  } else {
    displayClock(now);
  }

  delay(1000);  // Update every second
}

void displayClock(DateTime now) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(now.hour(), DEC);
  lcd.print(':');
  lcd.print(now.minute(), DEC);
  lcd.print(':');
  lcd.print(now.second(), DEC);
  lcd.print("  ");
  lcd.print(daysOfWeek[now.dayOfTheWeek()]);

  lcd.setCursor(0, 1);
  lcd.print(now.day(), DEC); lcd.print(' ');
  lcd.print(months[now.month() - 1]); lcd.print(' ');
  lcd.print(now.year());
  lcd.print(modeDisplay); // auto/manual mode display som
  //lcd.print(now.year() % 100);// to display only last 2 digits
}

void adjustTime(DateTime now) {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("Adjusting...");

  while (digitalRead(SELECT_BUTTON) == LOW) {
    lcd.setCursor(0, 1);
    lcd.print(getFieldName());
    lcd.setCursor(0, 0);

    // int value = now.get(selectedField);
    // lcd.print(value);
    int value;
    switch (selectedField) {
      case 0: value = now.hour();       break;
      case 1: value = now.minute();     break;
      case 2: value = now.day();        break;
      case 3: value = now.month();      break;
      case 4: value = now.year() % 100; break;
      default: value = 0;
    }

  lcd.print(value);


    if (selectedField == 3) {
      lcd.print(months[value - 1]);
    } else {
      lcd.print("  ");
    }

    lcd.blink();

    if (digitalRead(INCREMENT_BUTTON) == HIGH) {
      adjustValue(now, selectedField, 1);
    } else if (digitalRead(DECREMENT_BUTTON) == HIGH) {
      adjustValue(now, selectedField, -1);
    }

    delay(500);
  }

  lcd.noBlink();
  rtc.adjust(now);
}

void adjustValue(DateTime& now, int field, int delta) {
  // Adjust the specified field (Hour, Minute, Day, Month, Year) with delta
 now = now + TimeSpan(0, 0, 0, (field == 4) ? delta * 100 : delta);

}

String getFieldName() {
  switch (selectedField) {
    case 0: return "Hour: ";
    case 1: return "Min:  ";
    case 2: return "Day:  ";
    case 3: return "Month:";
    case 4: return "Year: ";
    default: return "";
  }
}