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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define button_pin 2
Adafruit_SSD1306 Oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

RTC_DS1307 rtc;
const float BETA = 3950;
unsigned long t1 = 0;
unsigned long time = 0;
bool a = false;
int s = 0;
int time_wait_button = 5; //5 seconds
int mode = 0;
int i = 0;
int c = 0;

int poz = 1;
int broj = 1;
int kretanjeY = 30;

int sec1 = 0;
int min1 = 0;
unsigned long msec = 0;
unsigned long mili = 0;
int pres = 0;
int fase = 0;
int start = 0;
unsigned long tim = 0;

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;
float celsius = 0;
// 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;
#define blue_pin 5
#define red_pin 3
#define green_pin 4
void setup()
{
  Serial.begin(9600);
  pinMode(blue_pin, OUTPUT);
  pinMode(red_pin, OUTPUT);
  pinMode(green_pin, OUTPUT);
  attachInterrupt(digitalPinToInterrupt(button_pin), button_isr, CHANGE);


  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }


  /// set data from serial and send to variables to show on oled

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

  Serial.print("Enter time in 24-hour format [hhmmss]: ");
  while (cnt < 6)
  {
    while (Serial.available() == 0) {};
    tmp = Serial.read();
    if ((tmp >= '0') and (tmp <= '9'))
    {
      buf[cnt] = tmp;
      cnt++;
      Serial.print(tmp);
    }
  }
  Serial.println();
  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");
  else
  {
    Serial.println(h);
    Serial.println(m);
    Serial.println(s);
    Serial.print("New time set to ");
    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)); // pass variables from serial to set time using library fucntion
  // SSD1306_SWITCHCAPVCC = generate Oled voltage from 3.3V internally
  Oled.begin(SSD1306_SWITCHCAPVCC, 0x3C); // Address 0x3C for 128x32

  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()
{
  int analogValue = analogRead(A0);
  celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  DateTime now = rtc.now();
  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
  // Serial.println(mode);
  if  (time >= 2 && time < 3 && s == 1)
  {
    s = 0;
    mode = 0;
    Serial.println("clock mode!");
    Oled.clearDisplay();
    Oled.display();
    delay(1000);
  }
  if  (time >= 3 && time < 4 && s == 1)
  {
    s = 0;
    mode = 1;
    Serial.println("Stop watch mode!");
    Oled.clearDisplay();
    Oled.display();
    delay(1000);
  }
  if  (time >= 4 && time < 5 && s == 1)
  {
    s = 0;
    mode = 2;
    Serial.println("Alarm mode!");
    Oled.clearDisplay();
    Oled.display();
    delay(1000);
  }

  if  (time >= 5 && s == 1)
  {
    s = 0;
    mode = 3;
    Serial.println("temp_display mode!");
    Oled.clearDisplay();
    Oled.display();
    delay(1000);
  }

  if (mode == 0)
  {

    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();

    }
  }

  if (mode == 1)

  {
    if (c == 1)
    {
      c = 0;
      Serial.println("in stop watch");
      Oled.clearDisplay();
      Oled.display();

    }
    Oled.clearDisplay();
    if (digitalRead(2) == 1)
    {
      if (pres == 0)
      {
        fase = fase + 1;
        pres = 1;
        if (fase > 2)
          fase = 0;
      }

    } else
    {
      pres = 0;
    }

    if (fase == 0)
    {
      Oled.clearDisplay();
      Oled.setTextSize(2);
      Oled.setTextColor(WHITE);
      Oled.setCursor(40, 32);
      Oled.print("Start");
      sec1 = 0;
      min1 = 0;
      tim = 0;
      mili = 0;
      msec = 0;
      start = 0;
    }

    if (fase == 1)
    {
      Oled.clearDisplay();
      Oled.setTextSize(2);
      Oled.setTextColor(WHITE);

      if (start == 0)
      {
        start = 1;
        tim = millis();
      }
      msec = (millis() - tim);



      min1 = msec / 60000;


      if ((msec / 1000) > 59)
      {
        sec1 = (msec / 1000) - (min1 * 60);
      } else {
        sec1 = msec / 1000;
      }

      mili = (msec % 1000) / 10;

      Oled.setCursor(38, 20);
      if (min1 <= 9)
      {
        Oled.print("0");
        Oled.print(min1);
      }
      else
      {
        Oled.print(min1);
      }

      Oled.print(":");

      if (sec1 <= 9)
      {
        Oled.print("0");
        Oled.print(sec1);
      } else {
        Oled.print(sec1);
      }
      Oled.setTextSize(2);
      Oled.setTextColor(WHITE);
      Oled.setCursor(45, 50);

      if (mili <= 9)
      {
        Oled.print("0");
        Oled.print(mili);
      } else {
        Oled.print(mili);
      }
    }

    if (fase == 2)
    {
      Oled.clearDisplay();
      Oled.setTextSize(2);
      Oled.setCursor(38, 20);
      if (min1 <= 9)
      {
        Oled.print("0");
        Oled.print(min1);
      } else {
        Oled.print(min1);
      }

      Oled.print(":");

      if (sec1 <= 9)
      {
        Oled.print("0");
        Oled.print(sec1);
      } else {
        Oled.print(sec1);
      }
      Oled.setTextSize(2);
      Oled.setTextColor(WHITE);
      Oled.setCursor(45, 50);

      if (mili <= 9)
      {
        Oled.print("0");
        Oled.print(mili);
      } else {
        Oled.print(mili);
      }
    }


    Oled.display();

  }

  if (mode == 2)
  {
    char buf[4];
    char tmp;
    int  cnt = 0;
    int  h, m;
    if (c == 1)
    {
      c = 0;
      Serial.println("Alarm Mode!");



      Serial.print("Enter time in 24-hour format to set the alarm! [hhmm]: ");
      while (cnt < 4)
      {
        while (Serial.available() == 0) {};
        tmp = Serial.read();
        if ((tmp >= '0') and (tmp <= '9'))
        {
          buf[cnt] = tmp;
          cnt++;
          Serial.print(tmp);
        }
      }
      Serial.println();
      h = ((buf[0] - '0') * 10) + (buf[1] - '0');
      m = ((buf[2] - '0') * 10) + (buf[3] - '0');
      if ((h > 23) or (m > 59))
        Serial.println("ERROR: Invalid time");
      else
      {
        Serial.println(h);
        Serial.println(m);
        Serial.print("New Alarm set to ");
        if (h < 10)
          Serial.print("0");
        Serial.print(h, DEC);
        Serial.print(":");
        if (m < 10)
          Serial.print("0");
        Serial.print(m, DEC);
      }

    }
    // Serial.println("h is: " + String(h));
    // Serial.println("m is: " + String(m));
    // Serial.println("rtc h is: " + String(c_hours));
    // Serial.println("rtc m is: " + String(c_mins));
    if (h == c_hours && m == c_mins)
    {
      tone(8, 262, 250);
      delay(500);
      noTone(8);
    }
  }

  if (mode == 3)
  {
    if (digitalRead(2) == 1)
    {
      if (pres == 0)
      {
        fase = fase + 1;
        pres = 1;
        if (fase > 1)
          fase = 0;
      }

    } else
    {
      pres = 0;
    }

    if (fase == 0)
    {
      Oled.clearDisplay();
      Oled.setTextSize(2);
      Oled.setTextColor(WHITE);
      Oled.setCursor(0, 0);
      String current_temp = String(celsius) + " C*";
      Oled.print(current_temp);
      Oled.display();
      if (celsius < 26)
      {
        digitalWrite(blue_pin, HIGH);
        digitalWrite(red_pin, LOW);
        digitalWrite(green_pin, LOW);
      }
      if (celsius < 40 && celsius >= 26)
      {
        digitalWrite(blue_pin, LOW);
        digitalWrite(red_pin, LOW);
        digitalWrite(green_pin, HIGH);
      }
      if (celsius >= 40)
      {
        digitalWrite(blue_pin, LOW);
        digitalWrite(red_pin, HIGH);
        digitalWrite(green_pin, LOW);
      }

    }
    if (fase == 1)
    {
      Oled.clearDisplay();
      Oled.display();
      digitalWrite(blue_pin, LOW);
      digitalWrite(red_pin, LOW);
      digitalWrite(green_pin, LOW);

    }
  }

}

void button_isr()
{

  if (digitalRead(button_pin) == HIGH)
  {
    t1 = millis();
  }
  else
  {
    time = (millis() - t1) / 1000;
    //  Serial.println(time);
    s = 1;
    c = 1;
  }
}