/*

  Pressing the button for more than 3 sedonds changes the mode
  Quick press considered short press
  Mode: 1. Clock
        2. Stopwatch

  Short press in Stopwatch mode starts the stopwatch. Second press stop the counting 
  and the third press resets it and start again.


*/

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 
#define SCREEN_HEIGHT 64 
#define OLED_RESET 1
#include "RTClib.h"
RTC_DS3231 rtc;
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
int timer = 0;
int mode = 0;
bool srt = false;
unsigned long prevTime = 0;
bool down = false;
unsigned long startMillis;
unsigned long currentMillis;
unsigned long elapsedMillis;
unsigned long allSeconds;

const float pi = 3.14159267 ;
const int clock_center_x=85;
const int clock_center_y=32;

int x,y,x1,y1;

int seconds=0;
int minutes;
int hours;

int runHours;
int secsRemaining;
int runMinutes;
int runSeconds;


void setup() {
  Serial.begin(9600);
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); 
  }

  attachInterrupt(digitalPinToInterrupt(2),modChan,CHANGE);
  int sec = InitSec();
  int minu = InitMin();
  int hr = InitHr();
  DateTime newTime = DateTime(0,0,0,hr,minu,sec);
  rtc.adjust(newTime);
  display.display();
  delay(2000); 
  display.clearDisplay();
  draw_clock_face();   
  display.display();

}

void modChan(){

  down = !down;
  if(down){
    prevTime = millis();
  }else{
    unsigned long duration = millis() - prevTime;
    timer = duration;
  }

  

}


int InitSec(){

  Serial.println("Input Seconds");
  while(!Serial.available()){;}

  int sec = Serial.readString().toInt();
  if(sec < 60 && sec > 0){

    return sec;

  } else{ return 0; }


}
int InitMin(){

  Serial.println("Input Minutes");
  while(!Serial.available()){;}

  int minu = Serial.readString().toInt();
  if(minu < 60 && minu > 0){

    return minu;

  } else{ return 0; }


}
int InitHr(){

  Serial.println("Input Hour");
  while(!Serial.available()){;}

  int hr = Serial.readString().toInt();
  if(hr < 24 && hr > 0){

    return hr;

  } else{ return 0; }


}

void draw_second(int second){
   y= (24*cos(pi-(2*pi)/60*second))+clock_center_y;
   x =(24*sin(pi-(2*pi)/60*second))+clock_center_x;
  display.drawCircle(x, y, 1, SSD1306_WHITE);
}

void draw_hour(int hour, int minute){
  
   y= (18*cos(pi-(2*pi)/12*hour-(2*PI)/720*minute))+clock_center_y;
   x =(18*sin(pi-(2*pi)/12*hour-(2*PI)/720*minute))+clock_center_x;
   y1=(18*cos(pi-(2*pi)/12*hour-(2*PI)/720*minute))+clock_center_y+1;
   x1=(18*sin(pi-(2*pi)/12*hour-(2*PI)/720*minute))+clock_center_x+1;
  display.drawLine(clock_center_x,clock_center_y,x,y,SSD1306_WHITE);
  display.drawLine(clock_center_x+1,clock_center_y+1,x1,y1,SSD1306_WHITE);
  
}

void draw_minute(int minute){
   y= (24*cos(pi-(2*pi)/60*minute))+clock_center_y;
   x =(24*sin(pi-(2*pi)/60*minute))+clock_center_x;
   display.drawLine(clock_center_x,clock_center_y,x,y,SSD1306_WHITE);
}

void draw_clock_face(void){

  display.clearDisplay();
  display.drawCircle(clock_center_x, clock_center_y,3, SSD1306_WHITE);
  display.fillCircle(clock_center_x, clock_center_y,3, SSD1306_WHITE);

  for (int i=0;i<12;i++){
    y= (32*cos(pi-(2*pi)/12*i))+clock_center_y;
    x =(32*sin(pi-(2*pi)/12*i))+clock_center_x;
    y1= (28*cos(pi-(2*pi)/12*i))+clock_center_y;
    x1 =(28*sin(pi-(2*pi)/12*i))+clock_center_x;
    display.drawLine(x1,y1,x,y,SSD1306_WHITE);
  } 

  display.drawCircle(26*sin(pi)+clock_center_x, (26*cos(pi))+clock_center_y, 6, SSD1306_BLACK);
  display.fillCircle(26*sin(pi)+clock_center_x, (26*cos(pi))+clock_center_y, 5, SSD1306_BLACK);
  display.setTextSize(1);             
  display.setTextColor(SSD1306_WHITE);        
  display.setCursor(clock_center_x-3,0);        
  display.println(F("12"));
}



void loop(){

  
  if (timer < 3000 && timer > 0){
    
    startMillis = millis();
    srt = !srt;
    timer = 0;


  } else if (timer > 3000){

    mode++;
    display.clearDisplay();
    timer = 0;


  }
  
  switch (mode){

    case(1):
      clock();
      break;
    case(2):
      stopWatch();
      break;
    default:
      mode = 1;
      break;
  }


}


void stopWatch(){


  if(srt == true){

    currentMillis = millis();
    elapsedMillis = (currentMillis - startMillis);
    allSeconds = elapsedMillis/1000;
    runHours= allSeconds/3600;
    secsRemaining=allSeconds%3600;
    runMinutes=secsRemaining/60;
    runSeconds=secsRemaining%60;
    display.clearDisplay();
  
  }
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  char buffer [16];
  sprintf (buffer, "%02d:%02d", runMinutes, runSeconds);
  display.setCursor(35,25);
  display.print(buffer);
  display.display();

  
}

void clock(){


  DateTime now = rtc.now();
  int thisSec, thisMin, thisHour;
  thisSec = now.second();
  thisMin = now.minute();
  thisHour = now.hour();
  draw_second(seconds);
  draw_minute(minutes);
  draw_hour(hours,minutes);
  draw_second(seconds);
  draw_minute(minutes);
  draw_hour(hours,minutes);
  display.display(); 
  seconds=thisSec;
  minutes=thisMin;
  hours=thisHour;
  draw_clock_face();
  char buffer [16];
  sprintf (buffer, "%02d:%02d:%02d", thisHour, thisMin, thisSec);
  display.setTextSize(0.5);
  display.setCursor(1,50);
  display.print(buffer);

}