// 74HC165 pins
const byte inputSelectPin = 2;
const byte clockPulsePin = 3;
const byte dataOutPin = 4;

// 74HC595 pins
const byte clearPin = 5;
const byte serialDataPin = 6;
const byte shiftClockPin = 7;
const byte latchClockPin = 8;

// Number of input buttons (adjust as needed)
const int numButtons = 8;

uint16_t inputData = 0; // Store input data
uint16_t previousData = 0; // Store the previous input data

byte mode = 0; // Store the selected mode: 0 for SIPO, 1 for PISO, 2 for PIPO, 3 for SISO

void setup() {
  // 74HC165 setup
  pinMode(inputSelectPin, OUTPUT);
  pinMode(clockPulsePin, OUTPUT);
  pinMode(dataOutPin, INPUT);

  // 74HC595 setup
  pinMode(clearPin, OUTPUT);
  pinMode(shiftClockPin, OUTPUT);
  pinMode(latchClockPin, OUTPUT);
  pinMode(serialDataPin, OUTPUT);
  digitalWrite(clearPin, LOW);
  digitalWrite(clearPin, HIGH);

  // Initialize serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Read input data from 74HC165
  inputData = readInputData();

  // Update the 74HC595 with the new input data
  updateOutputData(inputData);

  // Read mode selection from DIP switch (1 to 4)
  mode = readModeSelection();

  // Print data and mode for debugging
  printData(inputData);
  printMode(mode);

  // Delay before the next loop iteration
  delay(5000);
}

// Function to read input data from 74HC165
uint16_t readInputData() {
  uint16_t dataIn = 0;

  digitalWrite(inputSelectPin, LOW);
  digitalWrite(clockPulsePin, LOW);
  digitalWrite(clockPulsePin, HIGH);
  digitalWrite(inputSelectPin, HIGH);

  for (int j = 0; j < numButtons; j++) {
    bool buttonState = digitalRead(dataOutPin);
    dataIn |= (buttonState << j);

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

  return dataIn;
}

// Function to update 74HC595 with input data
void updateOutputData(uint16_t data) {
  digitalWrite(latchClockPin, LOW);
  shiftOut(serialDataPin, shiftClockPin, MSBFIRST, highByte(data));
  shiftOut(serialDataPin, shiftClockPin, MSBFIRST, lowByte(data));
  digitalWrite(latchClockPin, HIGH);
}

// Function to read mode selection from DIP switch (1 to 4)
byte readModeSelection() {
  // Use pins 9 to 12 for mode selection (1 to 4)
  byte modeSelection = 0;
  for (byte i = 9; i <= 12; i++) {
    modeSelection |= (digitalRead(i) << (i - 9));
  }
  return modeSelection;
}

// Function to print data for debugging
void printData(uint16_t data) {
  if (previousData != data) {
    previousData = data;
    
    Serial.print("Input Data (DEC): ");
    Serial.print(data, DEC);
    Serial.println();

    Serial.print("Input Data (BIN): ");
    Serial.print(data, BIN);
    Serial.println();
  }
}

// Function to print the selected mode for debugging
void printMode(byte selectedMode) {
  Serial.print("Selected Mode: ");
  switch (selectedMode) {
    case 0:
      Serial.println("SIPO");
      break;
    case 1:
      Serial.println("PISO");
      break;
    case 2:
      Serial.println("PIPO");
      break;
    case 3:
      Serial.println("SISO");
      break;
    default:
      Serial.println("Invalid Mode");
      break;
  }
}