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

RTC_DS1307 rtc;
Adafruit_SSD1306 Oled = Adafruit_SSD1306(128, 64, &Wire);

const float val_pi = 3.14159267 ;
const int center_of_clock_x_axis = 64; // center of oled
const int center_of_clock_y_axis = 32; // center of oled
int o = 1;

// variables used to calculate coordinates of points on the circle
int x;
int y;
int z;
int b;

// variables to store previous values read off RTC module
int seconds = 0;
int minutes;
int hours;
String current_mins = "";
String current_hours = "";
String current_secs = "";
String current_time = "";
int c_mins = 0;
int c_hours = 0;
int c_secs = 0;

void setup() {
  Serial.begin(9600);

  if (!Oled.begin(SSD1306_SWITCHCAPVCC, 0x3C))
  {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  }
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }


  // we set the time here from serial

  char buf[6];
  char tmp;
  int  cnt = 0;
  int  h, m, s;

  Serial.print("Enter time in 24-hour format [hhmmss]: ");
  while (cnt < 6) // we will keep here until all hours minutes and seconds have been set from serial
  {
    while (Serial.available() == 0) {};
    tmp = Serial.read();
    if ((tmp >= '0') and (tmp <= '9'))
    {
      buf[cnt] = tmp;
      cnt++;
      Serial.print(tmp);
    }
  }
  Serial.println();
  // these following conditios stop us from ebtering invalid time

  h = ((buf[0] - '0') * 10) + (buf[1] - '0');
  m = ((buf[2] - '0') * 10) + (buf[3] - '0');
  s = ((buf[4] - '0') * 10) + (buf[5] - '0');
  if ((h > 23) or (m > 59) or (s > 59))
  {
    Serial.println("ERROR: Invalid time");
    return;
  }
  else
  {
    Serial.println(h);
    Serial.println(m);
    Serial.println(s);
    Serial.print("time set to ");
    // simple conversions of time to display on serial monitors
    if (h < 10)
      Serial.print("0");
    Serial.print(h, DEC);
    Serial.print(":");
    if (m < 10)
      Serial.print("0");
    Serial.print(m, DEC);
    Serial.print(":");
    if (s < 10)
      Serial.print("0");
    Serial.print(s, DEC);
    Serial.println("...");
  }
  rtc.adjust(DateTime(2022, 9, 10, h, m, s)); // set the time using builtint library fucntion


  Oled.display();
  delay(2000); // Pause for 2 seconds

  // Clear the buffer
  Oled.clearDisplay();
  face_clock(); // fucntion that we used to make clock face
  Oled.display();



}

void draw_second_hand(int second, int mode)
{
  y = (24 * cos(val_pi - (2 * val_pi) / 60 * second)) + center_of_clock_y_axis;
  x = (24 * sin(val_pi - (2 * val_pi) / 60 * second)) + center_of_clock_x_axis;
  if (mode == 1) Oled.drawCircle(x, y, 2, SSD1306_WHITE);
  else Oled.drawCircle(x, y, 2, SSD1306_BLACK);
}

void draw_hour_hand(int hour, int minute, int mode)
{
  // calculations got from internet to make an hour hand
  y = (18 * cos(val_pi - (2 * val_pi) / 12 * hour - (2 * val_pi) / 720 * minute)) + center_of_clock_y_axis;
  x = (18 * sin(val_pi - (2 * val_pi) / 12 * hour - (2 * val_pi) / 720 * minute)) + center_of_clock_x_axis;
  b = (18 * cos(val_pi - (2 * val_pi) / 12 * hour - (2 * val_pi) / 720 * minute)) + center_of_clock_y_axis + 1;
  z = (18 * sin(val_pi - (2 * val_pi) / 12 * hour - (2 * val_pi) / 720 * minute)) + center_of_clock_x_axis + 1;
  if (mode == 1) {
    Oled.drawLine(center_of_clock_x_axis, center_of_clock_y_axis, x, y, SSD1306_WHITE);
    Oled.drawLine(center_of_clock_x_axis + 1, center_of_clock_y_axis + 1, z, b, SSD1306_WHITE);
  }
  else {
    Oled.drawLine(center_of_clock_x_axis, center_of_clock_y_axis, x, y, SSD1306_BLACK);
    Oled.drawLine(center_of_clock_x_axis + 1, center_of_clock_y_axis + 1, z, b, SSD1306_BLACK);
  }
}

void draw_minute_hand(int minute, int mode)
{
  // calculations got from internet to make an minute hand
  y = (24 * cos(val_pi - (2 * val_pi) / 60 * minute)) + center_of_clock_y_axis;
  x = (24 * sin(val_pi - (2 * val_pi) / 60 * minute)) + center_of_clock_x_axis;
  if (mode == 1)Oled.drawLine(center_of_clock_x_axis, center_of_clock_y_axis, x, y, SSD1306_WHITE); else Oled.drawLine(center_of_clock_x_axis, center_of_clock_y_axis, x, y, SSD1306_BLACK);
}

void face_clock(void)
{
  // draw the center of the clock
  Oled.drawCircle(center_of_clock_x_axis, center_of_clock_y_axis, 3, SSD1306_WHITE);
  Oled.fillCircle(center_of_clock_x_axis, center_of_clock_y_axis, 3, SSD1306_WHITE);

  // draw hour pointers around the face of a clock
  for (int i = 0; i < 12; i++) {
    y = (32 * cos(val_pi - (2 * val_pi) / 12 * i)) + center_of_clock_y_axis;
    x = (32 * sin(val_pi - (2 * val_pi) / 12 * i)) + center_of_clock_x_axis;
    b = (28 * cos(val_pi - (2 * val_pi) / 12 * i)) + center_of_clock_y_axis;
    z = (28 * sin(val_pi - (2 * val_pi) / 12 * i)) + center_of_clock_x_axis;
    Oled.drawLine(z, b, x, y, SSD1306_WHITE);
  }
  // print string "12" at the top of the face of the clock
  Oled.drawCircle(26 * sin(val_pi) + center_of_clock_x_axis, (26 * cos(val_pi)) + center_of_clock_y_axis, 6, SSD1306_BLACK);
  Oled.fillCircle(26 * sin(val_pi) + center_of_clock_x_axis, (26 * cos(val_pi)) + center_of_clock_y_axis, 5, SSD1306_BLACK);
  Oled.setTextSize(1);             // Normal 1:1 val_pixel scale
  Oled.setTextColor(SSD1306_WHITE);        // Draw white text
  Oled.setCursor(center_of_clock_x_axis - 3, 0);          // Start at top-left corner
  Oled.println(F("12"));
}

void draw_face_clock_reset(void)
{
  Oled.drawCircle(center_of_clock_x_axis, center_of_clock_y_axis, 3, SSD1306_WHITE);
  Oled.fillCircle(center_of_clock_x_axis, center_of_clock_y_axis, 3, SSD1306_WHITE);
  Oled.setCursor(center_of_clock_x_axis - 3, 0);
  Oled.println(F("12"));
}


void loop()
{
  // display.ClearDisplay();
  // Oled.clearDisplay();


  DateTime now = rtc.now();

  // Oled.display();
  Serial.println(current_time);
  // delay(1000);

  char buf1[] = "hh";
  char buf2[] = "mm";
  char buf3[] = "ss";
  current_hours = now.toString(buf1);
  current_mins = now.toString(buf2);
  current_secs = now.toString(buf3);
  c_mins = current_mins.toInt();  // current mins from rtc
  c_hours = current_hours.toInt() ; // current hours from rtc
  c_secs = current_secs.toInt(); // current secs from rtc

  if (c_secs != seconds) // make oled display seconds hand moving by clearing and displaying simultaneously
  {
    Oled.clearDisplay();
    Oled.setTextSize(0.5);
    Oled.setTextColor(WHITE);
    Oled.setCursor(0, 0);
    char buffe[] = "hh:mm";
    current_time = now.toString(buffe);
    Oled.print(current_time);
    face_clock();
    draw_face_clock_reset();
    draw_second_hand(c_secs, 0);
    draw_minute_hand(c_mins, 0);
    draw_hour_hand(c_hours, c_mins, 0);
    draw_second_hand(c_secs, 1);
    draw_minute_hand(c_mins, 1);
    draw_hour_hand(c_hours, c_mins, 1);
    seconds = c_secs;
    minutes = c_mins;
    hours = c_hours;
    Oled.display();

  }


}