#include <SPI.h>

#define btndebounce 100

#define load    25        // 74HC165 PL
#define clock   26        // Ortak clock pini
#define dataIn  27        // 74HC165 Q7

#define latch   32        // 74HC595 ST_CP
#define dataOut 33        // 74HC595 DS

uint32_t lastSwitchPress = 0;
uint32_t CurrentSwitchPress = 0;
uint8_t outputsUpdate = 0;  // Artık sadece 8-bit yeterli

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

  pinMode(load, OUTPUT);
  pinMode(clock, OUTPUT);
  pinMode(dataIn, INPUT);
  pinMode(latch, OUTPUT);
  pinMode(dataOut, OUTPUT);
}

void loop() {
  SN74165Control();
}

void SN74165Control() {
  CurrentSwitchPress = millis();
  if (CurrentSwitchPress - lastSwitchPress > btndebounce) {
    digitalWrite(load, LOW);
    delayMicroseconds(5);
    digitalWrite(load, HIGH);

    uint8_t incoming = shift8In(dataIn, clock, MSBFIRST);

    if (incoming > 0) {
      outputsUpdate ^= incoming;  // Toggle mantığı
      digitalWrite(latch, LOW);
      shift8Out(dataOut, clock, MSBFIRST, outputsUpdate);
      digitalWrite(latch, HIGH);

      Serial.print("Button States (binary): ");
      Serial.println(outputsUpdate, BIN);
    }
    lastSwitchPress = CurrentSwitchPress;
  }
}

uint8_t shift8In(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {
  uint8_t value = 0;
  for (int i = 0; i < 8; i++) {
    if (bitOrder == LSBFIRST)
      value |= (digitalRead(dataPin) << i);
    else
      value |= (digitalRead(dataPin) << (7 - i));

    digitalWrite(clockPin, HIGH);
    digitalWrite(clockPin, LOW);
  }
  return value;
}

void shift8Out(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val) {
  for (int i = 0; i < 8; i++) {
    if (bitOrder == LSBFIRST)
      digitalWrite(dataPin, !!(val & (1 << i)));
    else
      digitalWrite(dataPin, !!(val & (1 << (7 - i))));

    digitalWrite(clockPin, HIGH);
    digitalWrite(clockPin, LOW);
  }
}