#include <U8glib.h>
#include <RTClib.h>
U8GLIB_SSD1306_128X64 u8g;
RTC_DS1307 rtc;
int hour;
int minute;
int second;
int clockcenterX = 50;
int clockcenterY = 40;

void setup()
{
  Serial.begin(115200);
  Serial.setTimeout(5000);
  if (!rtc.begin())
  {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }
  // taking input from serial moniter 
  Serial.println("Enter Hour");
  while (Serial.available() == 0) {}
  hour = Serial.parseInt();
  Serial.println(hour);

  Serial.println("Enter minute");
  while (Serial.available() == 0) {}
  minute = Serial.parseInt();
  Serial.println(minute);

  Serial.println("Enter second");
  while (Serial.available() == 0) {}
  second = Serial.parseInt();
  Serial.println(second);

  u8g.setFont(u8g_font_7x13);
  rtc.adjust(DateTime(2021, 9, 27, hour, minute, second));
}

void loop()
{
  // taking time from rtc
  DateTime now = rtc.now();
  String hour = String ( now.hour(), DEC);
  String minute = String ( now.minute(), DEC);
  String second = String ( now.second(), DEC);
  u8g.firstPage();
  do
  {
    // creating analog clock 
    u8g.drawStr(0, 10, hour.c_str());
    u8g.drawStr(20, 10, ":");
    u8g.drawStr(30, 10, minute.c_str());
    u8g.drawStr(50, 10, ":");
    u8g.drawStr(60, 10, second.c_str());
    u8g.drawCircle(clockcenterX, clockcenterY, 20);
    u8g.drawCircle(clockcenterX, clockcenterY, 1);
    u8g.drawCircle(clockcenterX, clockcenterY, 17);
    drawSec(now.second());
    drawMin(now.minute());
    drawHour(now.hour(), now.minute());
    for (int d = 0 ; d < 12; d++)
    {
      drawMark(d);
    }
  }
  while (u8g.nextPage());
  u8g.setColorIndex(1);
}
// making of digital clock 
void drawMark(int d)
{
  float X_1, Y_1, X_2, Y_2;
  d = d * 30;
  d = d + 270;
  X_1 = 17 * cos(d * 0.0175);
  Y_1 = 17 * sin(d * 0.0175);
  X_2 = 20 * cos(d * 0.0175);
  Y_2 = 20 * sin(d * 0.0175);
  u8g.drawLine(X_1 + clockcenterX, Y_1 + clockcenterY, X_2 + clockcenterX, Y_2 + clockcenterY);
}
void drawSec(int s)
{
  float x1, y1 ;
  s = s * 6;
  s = s + 270;
  x1 = 15 * cos(s * 0.0175);
  y1 = 15 * sin(s * 0.0175);
  u8g.drawLine(x1 + clockcenterX, y1 + clockcenterY,  clockcenterX,  clockcenterY);
}
void drawMin(int m)
{
  float x1, y1;
  m = m * 6;
  m = m + 270;
  x1 = 13 * cos(m * 0.0175);
  y1 = 13 * sin(m * 0.0175);
  u8g.drawLine(x1 + clockcenterX, y1 + clockcenterY,  clockcenterX,  clockcenterY);
}
void drawHour(int h, int m)
{
  float x1, y1;
  h = (h * 30) + (m / 2);
  h = h + 270;
  x1 = 12 * cos(h * 0.0175);
  y1 = 12 * sin(h * 0.0175);
  u8g.drawLine(x1 + clockcenterX, y1 + clockcenterY, clockcenterX, clockcenterY);
}