#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Fonts/FreeSans9pt7b.h>
#include <Fonts/FreeSans12pt7b.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// SCL A5
// SDA A4
#define OLED_RESET 0  // GPIO0
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

//Adafruit_SSD1306 display(128, 32, &Wire);

int button1 = 2;
int button2 = 3;
int button1State = 0;
int button2State = 0;
int previousButton1State = 0;
unsigned long previousMillis = 0;
unsigned long currentMillis = 0;
int sec = 0;
int milli = 0;
bool running = false;

void setup() {
  pinMode(button1, INPUT_PULLUP);
  pinMode(button2, INPUT_PULLUP);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  //display.setTextSize();
  display.setTextColor(WHITE);
  display.display();
}

void loop() {
  button1State = digitalRead(button1);
  button2State = digitalRead(button2);
  currentMillis = millis();

  if (button2State == LOW) {
    sec = 0;
    milli = 0;
    running = false;
  }

  if (button1State == LOW && previousButton1State == HIGH && (currentMillis - previousMillis >= 100)) {
    if (running == false) {
      running = true;
    } else {
      running = false;
     
    }
    
    previousMillis = currentMillis;
     display.setFont(&FreeSans9pt7b);
        display.setFont();
        display.setCursor(25,38);
        display.print("press zero to start");

  }
  previousButton1State = button1State;
  

  if (running) {
    
    //msec=(millis();
    //milli=(msec%1000)/10;
    milli = milli + 1;
    if (milli >= 10) {
      sec = sec + 1;
      milli = 0;
    }
  }

  //display.clearDisplay();
  //display.setCursor(0, 0);
  display.clearDisplay();
        display.setFont(&FreeSans9pt7b);
        display.setFont();
        display.setCursor(25,0);
        display.print("Viscosity Time");
        display.setFont(&FreeSans12pt7b);
        display.setCursor(35,35);
  if (sec < 10) {
    display.print("00");
    display.print(sec);
    display.setCursor(75,35);
    display.print(",");
  } else if (sec < 100) {
    display.print("0");
    display.print(sec);
    display.setCursor(75,35);
    display.print(",");
  }else if (sec < 1000) {
    //display.print("0");
    display.print(sec);
    display.setCursor(75,35);
    display.print(",");
  }

  if (milli < 100) {
    display.setCursor(80,35);
    display.setFont(&FreeSans9pt7b);
    //display.print("0");
    display.print(milli);
    display.setCursor(95,35);
        display.print("s");
  } else {
    display.setCursor(80,35);
    display.setFont(&FreeSans9pt7b);
    display.print(milli);
    display.setCursor(95,35);
        display.print("s");
    
  }
  display.display();
  delay(10);
}