#include <Wire.h>
#include <RTClib.h>
#include <LiquidCrystal_I2C.h>
#define backlightButton 2
LiquidCrystal_I2C lcd(0x27, 16, 2);// ref: datasheet
RTC_DS3231 rtc;
String msg; String mode_Msg;
void setup() {
  Serial.begin(9600); 
  Wire.begin(); //to ensure I2C bus is properly initialized before any communication takes place.
  lcd.begin(16, 2); //lcd.backlight();
  // Initialize RTC
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1); delay(10);
  } if (rtc.lostPower()) { Serial.println("RTC lost power, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
  /////-----IMPORTANT ----------------------//
  // Uncomment the next line on the first run to set the correct time
  //  rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); 
  pinMode(backlightButton, INPUT_PULLUP);
}

void loop() {
  DateTime now = rtc.now();
  int currentHour  = now.hour();  int currentMin   = now.minute();  int currentSec  = now.second();
  int currentDay   = now.day();   int currentMonth = now.month();   int currentYear = now.year();
  int temp = rtc.getTemperature();
  int dayOfWeek = now.dayOfTheWeek(); //index to match a representation where Sunday is 1.
  //--------Clock function end ----------------------
  
  if(digitalRead(backlightButton)==LOW) { lcd.backlight(); }
  if(digitalRead(backlightButton)==HIGH){ lcd.noBacklight();}
  

  lcd.clear(); lcd.setCursor(0, 0);// clear screen & start at upper row
  printLcd(0, 0, String(currentHour)); printLcd(2, 0, ":");
  printLcd(3, 0, String(currentMin));   printLcd(5, 0, ":");
  printLcd(6, 0, String(currentSec));
  printLcd(9, 0, String(currentDay) + monthToString(currentMonth) + String(currentYear % 100));
  //---- LCD TOP ROW  ----ENDS
  //----- LCD Bottom row ------start
  printLcd(0, 1, dayToString(dayOfWeek));
  printLcd(4, 1, msg);
  printLcd(9, 1, String(temp - 3)); // to subtrack heat inside the box
  printLcd(11, 1, "C");
  printLcd(13, 1, mode_Msg);
  // ----- LCD Bottom row -----end
  delay(1000);  //delay for stability-- IMPORTANT

}
void printLcd (int shuru, int sesh, String myWords) { // For LCD Display
  lcd.setCursor(shuru, sesh);   lcd.print(myWords);
}
String monthToString(int month) {
  switch (month) {
    case 1:  return "Jan"; case 2:  return "Feb"; case 3:  return "Mar";
    case 4:  return "Apr"; case 5:  return "May"; case 6:  return "Jun";
    case 7:  return "Jul"; case 8:  return "Aug"; case 9:  return "Sep";
    case 10: return "Oct"; case 11: return "Nov"; case 12: return "Dec";
    default: return "";
  }
}
String dayToString(int theDay) {
  switch (theDay) {
    case 0: return  "Sun";    case 1: return  "Mon";   case 2: return  "Tue";
    case 3: return  "Wed"; case 4: return  "Thu"; case 5: return  "Fri";
    case 6: return  "Sat";  default: return "Invalid day";
  }
}//--------