#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h> //OLED display library
#include <Wire.h> //Allows communication of Arduino board and OLED display
#include "RTClib.h" //Real time clock library
#include <Fonts/FreeSans9pt7b.h>

RTC_DS1307 rtc; //create an instant of RTC

DateTime previous;
DateTime current;

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire);

int toggle_1;
int time_1;
int alpha_1;
float timer_1;
int trigger_1;
int alarm_1 = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);

  pinMode(2, INPUT_PULLUP);
  pinMode(2, INPUT_PULLUP);
  pinMode(6, INPUT);
  
  //check rtc connection
  if (!rtc.begin()) {
    Serial.println("Can Not Find RTC");
    Serial.flush();
    abort();
  }
  previous = rtc.now();
  //Calibrate the display
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // Address 0x3C for 128x32
  display.display();
  delay(1000);
  display.clearDisplay();
  display.display();

  toggle_1 = 0;
  time_1 = 0;
  alpha_1 = 0;
  trigger_1 = 0;

  attachInterrupt(digitalPinToInterrupt(2),pressIn,FALLING);
  attachInterrupt(digitalPinToInterrupt(3),pressOut,RISING);

}

void loop() {
  if(toggle_1 == 0){
    DateTime now = rtc.now();
    int hour = now.hour(); //Declare the hour 
    int minute = now.minute(); //Declare the minute
    int second = now.second(); //Declare the seconds
    // the following for loop changes the value of min if seonds reaches 60, same for hour
    for(int i=0;i<10;i++){
      clock(hour, minute, second);
      delay(1000);
      second++;

      if(second >= 60)
      {
        minute++;
      }

      second = second % 60;
      
      if(minute >= 60)
      {
        hour++;
      }
      
      minute = minute % 60;
      hour = hour % 24;
      if(toggle_1 == 1){
        i = 11;
      }
    }
  }
  else{ //If the condition above is not true then the following code is executed
    stopwatch();
  }
}

//The following executes when the button is pressed in
void pressIn()
{
  time_1 = millis();
}

//The following executes once the button is released
void pressOut()
{
  alpha_1 = millis() - time_1;
  if(alpha_1 > 300)
  {
    if(toggle_1 == 0)
    {
      toggle_1 = 1;
      Serial.end();
	    Serial.begin(9600);
      //Asks user to enter a value in seconds
      Serial.println("Enter alarm value");
    }
    else
    {
      toggle_1 = 0;
    }
  }
  else
  {
    if(trigger_1 == 0)
    {
      trigger_1 = 1;
      timer_1 = 0;
    
    }
    else
    {
      trigger_1 = 0;
    }
  }
}

//The following function creates the stopwatch
void stopwatch()
{
  display.setTextSize(2); 
  display.setTextColor(SSD1306_WHITE);
  display.clearDisplay();
  display.setCursor(45,15);
  display.print("TIME");
  display.setCursor(45,34);

  if(timer_1 > alarm_1)
  {
    analogWrite(4,200);
  }
  else
  {
    analogWrite(4,0);
  }

  if(trigger_1 == 1)
  {
    display.print(timer_1);
    timer_1 = timer_1 + 0.1;
    delay(10);  
  }
  else
  {
    display.print(timer_1);
  }

  display.display();

  while(Serial.available() == 0)
  {
    alarm_1 = (Serial.parseInt());
    Serial.println(alarm_1);
  }
}

//The following code creates the analog clock
void clock(int hour, int minute, int second)
{
  display.setTextSize(1); //Sets size of the font
  display.setTextColor(SSD1306_WHITE);  //Sets font and lines color to white

  const int r=15;
  const double rot=-M_PI/2;
  double x,y,x0,y0,anglerad;
  
  display.clearDisplay();
  display.drawPixel(24,24,WHITE);
  display.drawCircle(24,24,r,WHITE);

  for(int i=0;i<12;i++){
    int angled=360/12*i;
    anglerad=2*M_PI/12*i+rot;
    x=r*cos(anglerad);
    y=r*sin(anglerad);
    x0=(r-3)*cos(anglerad);
    y0=(r-3)*sin(anglerad);

    display.drawLine(24+x0,24+y0,24+x,24+y,WHITE);
  }

  //Prints the "TIME" on the LCD display at set coordinates
  display.setCursor(80,10);
  display.print("TIME");
  display.setCursor(70,24);
  //Prints the digital clock hour and minutes 
  display.print(hour);
  display.print(":");
  display.print(minute);
  display.print(":");

  anglerad=2*M_PI/12*(hour%12)+2*M_PI/12/60*minute+rot;
  x=(r-7)*cos(anglerad);
  y=(r-7)*sin(anglerad);
  x0=0;
  y0=0;
  display.drawLine(24+x0,24+y0,24+x,24+y,WHITE);
  
  //minute
  anglerad=2*M_PI/60*minute+rot;
  x=(r-5)*cos(anglerad);
  y=(r-5)*sin(anglerad);
  x0=0;
  y0=0;
  display.drawLine(24+x0,24+y0,24+x,24+y,WHITE);

  //second
  display.setCursor(105,24);
  display.print(second);
  
  anglerad=2*M_PI/60*second+rot;
  x=(r-2)*cos(anglerad);
  y=(r-2)*sin(anglerad);
  x0=0;
  y0=0;
  display.drawLine(24+x0,24+y0,24+x,24+y,WHITE);
 
  display.display();  
}