#include <Wire.h>
#include <LiquidCrystal.h>  // couldn't do without this include since this library is not included by default 
//(i am not using the Arduino IDE)

const int DS1307_ADDRESS = 0x68; // I2C address of DS1307 RTC

// LCD module connections (modify these as per your diagram.json)
const int rs = 12;
const int en = 11;
const int d4 = 5;
const int d5 = 4;
const int d6 = 3;
const int d7 = 2;

LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {

    Wire.begin();
    lcd.begin(16, 2); //16 cols, 2 rows
    
    
    // start i2c communication to initialize DS1307
    Wire.beginTransmission(DS1307_ADDRESS);
    Wire.write(0);
    Wire.endTransmission();

    Serial.begin(9600);
}

void loop() {

    // Request 7 bytes of data from DS1307
    Wire.beginTransmission(DS1307_ADDRESS);
    Wire.write(0);
    Wire.endTransmission();
    Wire.requestFrom(DS1307_ADDRESS, 7);

    int ss = BinaryToDec(Wire.read()  & 0x7F);  // remove clock halt bit
    int mm = BinaryToDec(Wire.read()); 
    int hh = BinaryToDec(Wire.read() & 0x3F);  //24 hour format
    Wire.read();  // we need to read a parameter that we dont need to get yy mm dd
    int DD = BinaryToDec(Wire.read()) ;
    int MM = BinaryToDec(Wire.read()) ;
    int YY = BinaryToDec(Wire.read()) ;

    Serial.print(DD);
    Serial.print("/");
    Serial.print(MM);
    Serial.print("/");
    Serial.print(YY);
    Serial.print(" ");
    Serial.print(hh);
    Serial.print(":");
    Serial.print(mm);
    Serial.print(":");
    Serial.println(ss);

    // Display date and time on the LCD
    displayDateTime(ss, mm, hh, DD, MM, YY);
    

    delay(1000);
}


int BinaryToDec(int val){   //conversion binary to decimal
    return (val / 16 * 10) + (val % 16);
}

void displayDateTime(int ss, int mm, int hh, int DD, int MM, int YY){
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(DD);
  lcd.print('/');
  lcd.print(MM);
  lcd.print('/');
  lcd.print(YY);

  lcd.setCursor(0, 1);
  if (hh < 10) lcd.print('0');
  lcd.print(hh);
  lcd.print(':');
  if (mm < 10) lcd.print('0');
  lcd.print(mm);
  lcd.print(':');
  if (ss < 10) lcd.print('0');
  lcd.print(ss);
}