/*
Ega Rizky Setiawan(21/479314/TK/52861)
*/

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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for SSD1306 display connected using I2C
#define OLED_RESET     -1 // Reset pin
#define SCREEN_ADDRESS 0x3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

//declare button class to manage buttons
class pushBtn{
  public:
  int btnPin;
  bool lastSteadyState = LOW;
  bool lastBounceState = LOW;
  bool isPressed;
  bool btnState;
  int* counter;
  int mod;
  const int debounceDelay = 50;
  unsigned long int lastDebounceTime = 0;

  pushBtn(int pinNumber, int modifier , int* count){
    btnPin = pinNumber;
    mod = modifier;
    counter = count;
  }

  //updatecounter
  void updateCounter(){
    *counter += mod;
    if(*counter < 0){
      *counter = 0; 
    }
  }
  //check if button is pressed
  void btnPressCheck(){
    btnState = digitalRead(btnPin);

    if((millis() - lastDebounceTime) > debounceDelay){
      if(btnState == LOW && lastSteadyState == HIGH){
        isPressed == true;
        updateCounter();
      }
      else if(btnState == HIGH && lastSteadyState == LOW){
        isPressed = false;
      }
      lastSteadyState = btnState;
    }
    if(btnState != lastBounceState){
      lastDebounceTime = millis();
      lastBounceState = btnState;
    }
  }
  //
};

//function for display main screen
void mainDisplay(int counter){
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(20, 10);
  display.println("Counter: ");
  display.setTextSize(3);
  display.setCursor(55, 35);
  display.println(String(counter));
  display.display();
}

//function for display reset
void resetDisplay(){
  display.clearDisplay();
  display.setTextSize(3);
  display.setCursor(20, 10);
  display.println("RESET");
  display.display();
  delay(1000);
}

//declare pin for button
const int upBtnPin = 12;
const int downBtnPin = 14;
int counter = 0;

//variable for reset function
const unsigned int resetDelay = 2000;
unsigned long int resetTime = 0;
bool waitloop = false;

//instance up and down button object
pushBtn upBtn(upBtnPin, 1, &counter);
pushBtn downBtn(downBtnPin, -1, &counter);


//function for reset 
void resetCheck(){
  if(upBtn.isPressed && downBtn.isPressed){
    
    if((millis() - resetTime) > resetDelay){
      if(waitloop){
        counter = 0;
        resetDisplay();
      }
      waitloop = true;
      resetTime = millis();
    }
  }
  else{
    waitloop = false;
  }
}

void setup() {
  Serial.begin(115200);

  // Checks if the OLED is connected or not.
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }

  // Shows the Adafruit splash screen
  display.display();
  delay(1000);
  display.clearDisplay();

  // Use internal pullups for buttons
  pinMode(upBtnPin, INPUT_PULLUP);
  pinMode(downBtnPin, INPUT_PULLUP);
}

void loop() {
  mainDisplay(counter); //display main screeen
  upBtn.btnPressCheck(); // check if up button is pressed
  downBtn.btnPressCheck(); // check if down button is pressed
  resetCheck(); // check if both up and down button is pressed
}