#include <Tiny4kOLED_TinyWireM.h>

//int button
const int adjPin = 4; //button pin on P4 of ATtiny85. P5 is a reset and you won't have a good time tying that to ground!

//int variables
int seconds = 0;
int minutes = 0;
int hours = 0;

//time test values
unsigned long current = 0; //current time at test after second has elapsed
unsigned long previous = 0;   //time at previous test for second that has elapsed
unsigned long period = 1000;  //period between tests (millis)

int buttonState = 0;

void setup() { // put your setup code here, to run once:
  
  pinMode(adjPin, INPUT_PULLUP);
  oled.begin(128, 64, sizeof(tiny4koled_init_128x64r),tiny4koled_init_128x64r);
  oled.clear();
  oled.on();
  oled.setFont(FONT8X16);
  oled.setCursor(28,1);
  oled.println("Dumbwatch");
  oled.setCursor(36,3);
  oled.println("by Maso");
  delay(3000); //for boot screen
  oled.clear();

}

void loop() { // put your main code here, to run repeatedly
  timer();
  screen();
  button();
}
  
void timer() {
  current = millis(); //check to see if interval(second) has passed                
  
  if(current - previous >= period){   
    previous = current; //save last time second passed
    
    if(seconds < 59){ //  Check if a minute has elapsed.
      seconds++; //  Increment seconds,
      } else {
        seconds = 0;                        //  or reset seconds,  
    if(minutes < 59){ //  Check if an hour has elapsed.
        minutes++; //  then increment minutes,
      } else {
        minutes = 0; //  or reset minutes,
    if(hours < 23){ //  Check if a day has elapsed.
      hours++; //  then increment hours,
      } else {
        hours = 0; //  or reset hours.
        }
      }
    }
    } else if(current - previous < 0){ //time correction, skips increment. CAN CAUSE DELAY
      previous = 0;
} 
}
  
void screen(){
  oled.setFontX2(FONT8X16);
  oled.setCursor(24, 1); //set to x = 24 for HH:MM. For full debug set to x = 0
  //oled.print("HH:MM:SS"); //placeholder
  //oled.print("HH:MM"); //also placeholder
  if(hours < 10) {
    oled.print("0"); //add leading zeroes
  }
  oled.print(hours);
  oled.print(":");
  if(minutes < 10) {
    oled.print("0"); //add leading zeroes
  }
  oled.print(minutes);
  
  //oled.print(":");
  //oled.print(seconds);
}

void button() {
  buttonState = digitalRead(adjPin);
  if(buttonState == LOW) { 
    minutes++;
  } 
  if(minutes > 59) {
    hours++;
    minutes = 0;
  }
  if(hours > 23) {
    hours = 0;
  }
}