#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "RTClib.h"

RTC_DS1307 rtc; //create an instant of RTC

#define SCREEN_WIDTH 128 // OLED display width,  in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// declare an SSD1306 display object connected to I2C
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

DateTime current;
unsigned long time; 
long int seconds=0; 
long int mills=0;
int minutes=0; 
int hours=0; 
int set=0; 
int reset=0; 
const byte Button = 2;

void setup(){
  // initialize OLED display with address 0x3C for 128x64
  pinMode(Button, INPUT);
  attachInterrupt(digitalPinToInterrupt(2), stopwatch, CHANGE);
  Serial.begin(115200);

//check rtc connection
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }

if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
  Serial.println(F("SSD1306 allocation failed"));
  while (true);
}
delay(2000);         // wait for initializing
  oled.clearDisplay(); // clear display
}  

void loop() {
  // put your main code here, to run repeatedly:
  oled.clearDisplay();
  stopwatch();
  oled.display();

}

void display(DateTime now){
  oled.setTextSize(2);          // text size
  oled.setTextColor(WHITE);     // text color
  oled.setCursor(17, 22);        // position to display
  oled.print(now.hour(), DEC);//get current hour
  oled.print(':');
  oled.print(now.minute(), DEC); //get current minute
  oled.print(':');
  oled.print(now.second(), DEC); //get current second
  oled.println();
  oled.display();               // show on OLED
  
  oled.clearDisplay();
}

/////////////////////digital clock
void digitalClock(){
  current = rtc.now(); //get the current time

  display(current);
  delay(1000);

}

//////////////////////stopwatch starts
void setStopwatch(){
  seconds++;       //counts seconds from 0 
delay(1000);     //a delay of 1000 milliseconds is given for each second count 
if (seconds>59) 
{ 
seconds=0;      //whenever second is greater than 59 than second is made equal to 
minutes++;     // zero and a minute is counted for it 
} 
if (minutes>59) 
{hours++; 
minutes=0; 
} 
if(hours>23) 
{ 
hours=0; 
} 

}

void stopwatch(){
  if(digitalRead(Button) && !reset) // check if button is pressed /held "HIGH" and reset is false
  {
     time = millis();
     reset = true;
  }

  if(!digitalRead(Button) && reset) //Check if button is released "LOW" and reset is true
   { 
    reset = false;
   }
    
  if(digitalRead(Button) && (millis() - time > 3000)) // if button is HIGH and 3 seconds has passed, LED on.
  {

  setStopwatch();
  oled.setTextSize(2);          // text size
  oled.setTextColor(WHITE);     // text color
  oled.setCursor(17, 22);     //sets the cursor to 0th column and 1st row,numbering starts from 0 
{ 
if(hours<10)        //suppose 4 
{ 
oled.print("0");     //LCD first prints 0 and stopwatch shows 0 
oled.print(hours);       //LCD then prints 4. So value printed is 04 stopwatch shows 04 
} 
else 
{ 
oled.print(hours); 
} 
} 
oled.print(":"); 
{ 
if(minutes<10) 
{ 
oled.print("0"); 
oled.print(minutes); 
oled.print(":"); 
} 
else 
{ 
oled.print(minutes); 
oled.print(":"); 
} 
} 
{ 
if(seconds<10) 
{ 
oled.print("0"); 
oled.print(seconds); 
} 
else 
{ 
oled.print(seconds); 
} 
} 
} 
}