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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

unsigned long startTime = 0;
unsigned long lastSecondUpdate = 0;
 volatile boolean bTime    = false;
  hw_timer_t *timer = NULL;

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

  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("Error initializing OLED display."));
    for(;;);
  }

  display.display();
  delay(2000);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  timer = timerBegin(0,80,true);
  timerAttachInterrupt(timer,blink,true);
  timerAlarmWrite(timer,1000000,true);
  timerAlarmEnable(timer);

  timerRestart(timer);
  timerStart(timer);
  timerStop(timer);
}

void ARDUINO_ISR_ATTR blink ()
{
  bTime = true;
   runStopwatchOnOLED();
  
}


void loop() {

  //bTime = false; 
}

void runStopwatchOnOLED() {
  unsigned long currentMillis = millis();
  unsigned long elapsedTime = currentMillis - startTime;
  unsigned long minutes = elapsedTime / (60 * 1000);
  unsigned long seconds = (elapsedTime / 1000) % 60;
  unsigned long milliseconds = (elapsedTime % 1000) / 10; // Milliseconds divided by 10 for display

  // Update display only if seconds have changed
  if (seconds != lastSecondUpdate) {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.print("Timer:");
    display.setCursor(0, 10);
    if (minutes < 10) display.print("0");
    display.print(minutes);
    display.print(":");
    if (seconds < 100) display.print("0");
    display.print(seconds);
    display.print(".");
    if (milliseconds < 10) display.print("0");
      display.print(milliseconds);
    display.display();
    
    lastSecondUpdate = seconds;
  }

  if (seconds >= 59 && currentMillis - lastSecondUpdate >= 990) { // When seconds reach 59 and almost 1 second has passed since last update
    startTime += 1000; // Increment start time by 1 minute
    lastSecondUpdate = 0; // Reset last second update
  }

  
}

void startTimer() {
  if (startTime == 0) { // Only start if the timer is not already running
    startTime = millis();
  }
}

void stopTimer() {
  startTime = 0; // Reset the start time to stop the timer
}