#define DATA_PIN   PA7   // DS
#define LATCH_PIN  PA5   // STCP
#define CLOCK_PIN  PA4   // SHCP
#define BUTTON_PIN PC13  // Кнопка

bool direction = true;   // true = вправо, false = влево
int ledIndex = 0;
bool lastButtonState = HIGH;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;

void setup() {
  pinMode(DATA_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);

  // В Wokwi важно задать подтяжку программно:
  pinMode(BUTTON_PIN, INPUT);
  digitalWrite(BUTTON_PIN, HIGH);  // подтяжка к VCC вручную

  updateShiftRegister(0x00);
}

void loop() {
  bool reading = digitalRead(BUTTON_PIN);

  // антидребезг
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (lastButtonState == HIGH && reading == LOW) {
      direction = !direction;
    }
  }

  lastButtonState = reading;

  // бегущий огонь
  updateShiftRegister(1 << ledIndex);

  if (direction) {
    ledIndex++;
    if (ledIndex > 7) ledIndex = 0;
  } else {
    ledIndex--;
    if (ledIndex < 0) ledIndex = 7;
  }

  delay(150);
}

void updateShiftRegister(uint8_t data) {
  digitalWrite(LATCH_PIN, LOW);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, data);
  digitalWrite(LATCH_PIN, HIGH);
}