const int digitPins[4] = {4, 19, 21, 22};
const int clockPin = 18;
const int latchPin = 5;
const int dataPin = 23;
const int secondIndicatorPin = 15;  
const int buttonPin1 = 12;       //2         
const int buttonPin2 = 16;       //1   
const int resetButtonPin = 14;   //3      
const int reverseCountPin = 2;   //l   
const int ledPin = 17;           //r   

const byte digit[10] = {
    B00111111, // 0
    B00000110, // 1
    B01011011, // 2
    B01001111, // 3
    B01100110, // 4
    B01101101, // 5
    B01111101, // 6
    B00000111, // 7
    B01111111, // 8
    B01101111  // 9
};

int digitBuffer[4] = {0};
int digitScan = 0;

int buttonState1 = HIGH;
int lastButtonState1 = HIGH;
unsigned long lastDebounceTime1 = 0;
const int debounceDelay = 1;
int clickCount = 0;

int buttonState2 = HIGH;
int lastButtonState2 = HIGH;
unsigned long lastDebounceTime2 = 0;

int resetButtonState = HIGH;
int lastResetButtonState = HIGH;
unsigned long lastDebounceTimeReset = 0;

int reverseCountState = HIGH;
int lastReverseCountState = HIGH;

void setup()
{
    Serial.begin(115200);
    delay(5);

    for (int i = 0; i < 4; i++)
    {
        pinMode(digitPins[i], OUTPUT);
    }

    pinMode(latchPin, OUTPUT);
    pinMode(clockPin, OUTPUT);
    pinMode(dataPin, OUTPUT);
    pinMode(secondIndicatorPin, OUTPUT); 
    pinMode(buttonPin1, INPUT);
    pinMode(buttonPin2, INPUT);
    pinMode(resetButtonPin, INPUT);
    pinMode(reverseCountPin, INPUT);
    pinMode(ledPin, OUTPUT);

    Serial.println("Press the buttons to increment or reset the counter.");
}

void updateDisp()
{
    for (byte j = 0; j < 4; j++)
        digitalWrite(digitPins[j], LOW);

    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, B11111111);
    digitalWrite(latchPin, HIGH);

    delayMicroseconds(5);
    digitalWrite(digitPins[digitScan], HIGH);

    digitalWrite(latchPin, LOW);
    if (digitScan == 0)
        shiftOut(dataPin, clockPin, MSBFIRST, ~(digit[digitBuffer[digitScan]] | B10000000));
    else
        shiftOut(dataPin, clockPin, MSBFIRST, ~digit[digitBuffer[digitScan]]);

    digitalWrite(latchPin, HIGH);
    digitScan++;
    if (digitScan > 3)
        digitScan = 0;
}

void handleButtonPress1()
{
    clickCount += 100;
}

void handleButtonPress2()
{
    if (clickCount < 9999)
    {
        clickCount++;
    }
    else
    {
        clickCount = 0;
    }
}

void handleResetButtonPress()
{
    clickCount = 0;
}

void loop()
{
    int reading1 = digitalRead(buttonPin1);
    if (reading1 != lastButtonState1)
    {
        lastDebounceTime1 = millis();
    }

    if ((millis() - lastDebounceTime1) > debounceDelay)
    {
        if (reading1 != buttonState1)
        {
            buttonState1 = reading1;

            if (buttonState1 == LOW)
            {
                handleButtonPress1();
            }
        }
    }

    lastButtonState1 = reading1;

    int reading2 = digitalRead(buttonPin2);
    if (reading2 != lastButtonState2)
    {
        lastDebounceTime2 = millis();
    }

    if ((millis() - lastDebounceTime2) > debounceDelay)
    {
        if (reading2 != buttonState2)
        {
            buttonState2 = reading2;

            if (buttonState2 == LOW)
            {
                if (reverseCountState == HIGH)
                {
                    handleButtonPress2();
                }
                else
                {
                    clickCount--;
                    if (clickCount < 0)
                    {
                        clickCount = 9999;
                    }
                }
            }
        }
    }

    lastButtonState2 = reading2;

    int resetButtonReading = digitalRead(resetButtonPin);
    if (resetButtonReading != lastResetButtonState)
    {
        lastDebounceTimeReset = millis();

        if (resetButtonReading == LOW)
        {
            handleResetButtonPress();
        }
    }

    lastResetButtonState = resetButtonReading;

    int reverseCountReading = digitalRead(reverseCountPin);
    if (reverseCountReading != lastReverseCountState)
    {
        lastDebounceTime2 = millis();

        if (reverseCountReading == LOW)
        {
            reverseCountState = LOW;
        }
        else
        {
            reverseCountState = HIGH;
        }
    }

    lastReverseCountState = reverseCountReading;

    digitBuffer[3] = clickCount / 1000;
    digitBuffer[2] = (clickCount % 1000) / 100;
    digitBuffer[1] = (clickCount % 100) / 10;
    digitBuffer[0] = clickCount % 10;

    if (clickCount % 5 != 0)
    {
        digitalWrite(ledPin, HIGH);
    }
    else
    {
        digitalWrite(ledPin, LOW);
    }

    updateDisp();

    delay(1);
}