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

RTC_DS1307 rtc;
#define SCREEN_WIDTH 128 //--> OLED display width, in pixels
#define SCREEN_HEIGHT 64 //--> OLED display height, in pixels

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

byte _day, _month, _hour24, _hour12, _minute, _second, _dtw;
int _year;
byte hr24;

byte clockCenterX=31;
byte clockCenterY=31;

const unsigned char Clock_Frame [] PROGMEM = {
  0x00, 0x00, 0x00, 0x3f, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xff, 0xff, 0x80, 0x00, 0x00, 
  0x00, 0x00, 0x1f, 0xe0, 0x0f, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0xfc, 0x00, 0x00, 
  0x00, 0x00, 0xf0, 0x18, 0x70, 0x1e, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x28, 0x88, 0x07, 0x80, 0x00, 
  0x00, 0x07, 0x00, 0x08, 0x08, 0x01, 0xc0, 0x00, 0x00, 0x1c, 0x00, 0x08, 0x10, 0x00, 0x70, 0x00, 
  0x00, 0x38, 0x20, 0x08, 0x20, 0x10, 0x38, 0x00, 0x00, 0x70, 0x20, 0x08, 0x40, 0x10, 0x1c, 0x00, 
  0x00, 0xe0, 0x10, 0x3e, 0xf8, 0x20, 0x0e, 0x00, 0x01, 0xc0, 0x10, 0x00, 0x00, 0x20, 0x07, 0x00, 
  0x01, 0x80, 0x08, 0x00, 0x00, 0x40, 0x03, 0x00, 0x03, 0x00, 0x08, 0x00, 0x00, 0x40, 0x01, 0x80, 
  0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 
  0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 
  0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x30, 0x38, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x18, 0x38, 
  0x30, 0x30, 0x00, 0x00, 0x00, 0x00, 0x60, 0x18, 0x30, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 
  0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 
  0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 
  0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 
  0xc7, 0x00, 0x00, 0x03, 0x80, 0x00, 0x01, 0xc6, 0xc8, 0x80, 0x00, 0x07, 0xc0, 0x00, 0x02, 0x26, 
  0xc8, 0x80, 0x00, 0x0c, 0x60, 0x00, 0x00, 0x26, 0xc7, 0x80, 0x00, 0x0c, 0x60, 0x00, 0x00, 0xc6, 
  0xc0, 0x80, 0x00, 0x0c, 0x60, 0x00, 0x00, 0x26, 0xc1, 0x00, 0x00, 0x07, 0xc0, 0x00, 0x02, 0x26, 
  0xce, 0x00, 0x00, 0x03, 0x80, 0x00, 0x01, 0xc6, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 
  0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 
  0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 
  0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x30, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 
  0x30, 0x30, 0x00, 0x00, 0x00, 0x00, 0x60, 0x18, 0x38, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x18, 0x38, 
  0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x30, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 
  0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 
  0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x03, 0x00, 0x08, 0x00, 0x00, 0x20, 0x01, 0x80, 
  0x01, 0x80, 0x08, 0x00, 0x00, 0x20, 0x03, 0x00, 0x01, 0xc0, 0x10, 0x00, 0x00, 0x10, 0x07, 0x00, 
  0x00, 0xe0, 0x10, 0x03, 0x80, 0x10, 0x0e, 0x00, 0x00, 0x70, 0x20, 0x06, 0x00, 0x08, 0x1c, 0x00, 
  0x00, 0x38, 0x20, 0x04, 0x00, 0x08, 0x38, 0x00, 0x00, 0x1c, 0x00, 0x07, 0x80, 0x00, 0x70, 0x00, 
  0x00, 0x07, 0x00, 0x04, 0x40, 0x01, 0xc0, 0x00, 0x00, 0x03, 0xc0, 0x04, 0x40, 0x07, 0x80, 0x00, 
  0x00, 0x00, 0xf0, 0x03, 0x80, 0x1e, 0x00, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0xfc, 0x00, 0x00, 
  0x00, 0x00, 0x1f, 0xe0, 0x0f, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x03, 0xff, 0xff, 0x80, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x3f, 0xf8, 0x00, 0x00, 0x00
};

unsigned long previousMillisGetTimeDate = 0; //--> will store last time was updated
const long intervalGetTimeDate = 1000; //--> interval (milliseconds

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

  if (! rtc.isrunning()) {
    Serial.println("RTC is NOT running!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); //-> If that doesn't work, use this line of code outside of "if (! rtc.isrunning())"
  }
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); //--> Don't proceed, loop forever
  }
  delay(1000);
}

void loop() {
unsigned long currentMillisGetTimeDate = millis();
  if (currentMillisGetTimeDate - previousMillisGetTimeDate >= intervalGetTimeDate) {
    previousMillisGetTimeDate = currentMillisGetTimeDate;

    GetDateTime();
    
    display.clearDisplay();
    
    Draw_Clock_Frame();
    Analog_Clock(_hour12,_minute,_second);

    display.display();
  }
}

void GetDateTime(){
  DateTime now = rtc.now();
  _day=now.day();
  _month=now.month();
  _year=now.year();
  _hour24=now.hour();
  _minute=now.minute();
  _second=now.second();
  _dtw=now.dayOfTheWeek();

  hr24=_hour24;
  if (hr24>12) {
    _hour12=hr24-12;
  }
  else if (hr24==0) {
    _hour12=12;
  }
  else {
    _hour12=hr24;
  }
}
void Analog_Clock(byte h, byte m, byte s) {
  Draw_Line_Seconds(s);
  Draw_Line_Minutes(m);
  Draw_Line_Hours(h,m);
  
  for (byte i = 30; i < 33; i++) {
    display.drawPixel(i, 30, SSD1306_BLACK);
    display.drawPixel(i, 31, SSD1306_BLACK);
    display.drawPixel(i, 32, SSD1306_BLACK);
  }
}

void Draw_Line_Seconds(int s) {
  float angle = s * 6 ;
  angle = (angle / 57.29577951); //--> Convert degrees to radians 
   
  // 16 is the length of the "second line" on the Analog Clock
  int xS = (clockCenterX + (sin(angle) * (16)));
  int yS = (clockCenterY - (cos(angle) * (16)));

  //----------------------------------------Special condition at the 15th second, because at that second the line is not symmetrical
  if (s == 15) {
    display.drawLine(clockCenterX, clockCenterY, xS, yS + 1, WHITE);
  } else {
    display.drawLine(clockCenterX, clockCenterY, xS, yS, WHITE);
  }
}

//________________________________________________________________________Subroutine for drawing Minutes on an Analog Clock
void Draw_Line_Minutes(int m) {
  float angle = m * 6 ;
  angle = (angle / 57.29577951) ; //Convert degrees to radians  

  // 17 is the length of the "minute line" on the Analog Clock
  int xM = (clockCenterX + (sin(angle) * (17)));
  int yM = (clockCenterY - (cos(angle) * (17)));

  //----------------------------------------Special condition at minute 15, because at that minute the line is not symmetrical
  if (m == 15) {
    display.drawLine(clockCenterX, clockCenterY - 1, xM, yM + 1, WHITE);
    display.drawLine(clockCenterX - 1, clockCenterY, xM, yM + 1, WHITE);
    display.drawLine(clockCenterX, clockCenterY, xM, yM + 1, WHITE);
    display.drawLine(clockCenterX + 1, clockCenterY, xM, yM + 1, WHITE);
    display.drawLine(clockCenterX, clockCenterY + 1, xM, yM + 1, WHITE);
  } else {
    display.drawLine(clockCenterX, clockCenterY - 1, xM, yM, WHITE);
    display.drawLine(clockCenterX - 1, clockCenterY, xM, yM, WHITE);
    display.drawLine(clockCenterX, clockCenterY, xM, yM, WHITE);
    display.drawLine(clockCenterX + 1, clockCenterY, xM, yM, WHITE);
    display.drawLine(clockCenterX, clockCenterY + 1, xM, yM, WHITE);
  }
}
//________________________________________________________________________Subroutine for drawing Hour on an Analog Clock
void Draw_Line_Hours(int h, int m) {
  float angle = h * 30 + int((m / 12) * 6);
  angle = (angle / 57.29577951) ; //Convert degrees to radians
  // 12 is the length of the "hour line" on the Analog Clock
  int xH = (clockCenterX + (sin(angle) * (12)));
  int yH = (clockCenterY - (cos(angle) * (12)));
  //----------------------------------------Special condition at 12 o'clock, because at that hour the line is not symmetrical
  if (h == 12 && m < 12) {
    display.drawLine(clockCenterX, clockCenterY - 2, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX - 2, clockCenterY, xH + 1, yH, WHITE);    
    display.drawLine(clockCenterX, clockCenterY - 1, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX - 1, clockCenterY, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX, clockCenterY, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX + 1 ,clockCenterY, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX, clockCenterY + 1, xH + 1, yH, WHITE);
    display.drawLine(clockCenterX + 2, clockCenterY, xH + 1, yH ,WHITE);
    display.drawLine(clockCenterX, clockCenterY + 2, xH + 1, yH, WHITE);
  } else {
    display.drawLine(clockCenterX, clockCenterY - 2, xH, yH, WHITE);
    display.drawLine(clockCenterX - 2, clockCenterY, xH, yH, WHITE);    
    display.drawLine(clockCenterX, clockCenterY - 1, xH, yH, WHITE);
    display.drawLine(clockCenterX - 1, clockCenterY, xH, yH, WHITE);
    display.drawLine(clockCenterX, clockCenterY, xH, yH, WHITE);
    display.drawLine(clockCenterX + 1 ,clockCenterY, xH, yH, WHITE);
    display.drawLine(clockCenterX, clockCenterY + 1, xH, yH, WHITE);
    display.drawLine(clockCenterX + 2, clockCenterY, xH, yH ,WHITE);
    display.drawLine(clockCenterX, clockCenterY + 2, xH, yH, WHITE);
  }
}
//________________________________________________________________________Subroutine for drawing frames on an analog clock
void Draw_Clock_Frame() {
  display.drawBitmap(0, 0, Clock_Frame, 63, 63, WHITE); //--> display.drawBitmap(x position, y position, bitmap data, bitmap width, bitmap height, color)
}