const int LEDS[16] = {27,25, 26, 23, 22, 19, 18, 5, 17, 16, 4, 0, 2, 15, 12, 14};
const int IN_LEDS[3][4] = {{19, 18, 5, 17}, {16, 4, 0, 2},{22,23,22,23}};
const int OUT_LEDS[5] = {12, 14, 27, 26, 25};


long input1, input2, result, op;

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


  for (int a = 0; a < 16; a++) {
    pinMode(LEDS[a], OUTPUT);
  }
}

void outLeds(int num, int index) {
  String binaryStr = String( num, BIN);
  binaryStr = ("0000" + binaryStr).substring(binaryStr.length());

  for (int a  = 0; a < 4; a++) {
    digitalWrite(IN_LEDS[index][a], binaryStr.charAt(a) == '1' ? HIGH : LOW);
  }
}


void resultLeds(int num) {
  String binaryStr = String( num, BIN);
  binaryStr = ("00000" + binaryStr).substring(binaryStr.length());

  for (int a  = 0; a < 5; a++) {
    digitalWrite(OUT_LEDS[a], binaryStr.charAt(a) == '1' ? HIGH : LOW);
  }
}

void loop() {
  Serial.println("Input any key to start... ");
  while (Serial.available() == 0)
  {
  }

 
  Serial.readString();


  for (int a = 0; a < 16; a++) {
    digitalWrite(LEDS[a], LOW);
  }

  Serial.print("Enter the first number: ");
  while (Serial.available() == 0)
  {
  }


  input1 = Serial.readString().toInt();
  Serial.println(input1);


  outLeds(input1, 0);

  Serial.print("Enter the second number: ");
  while (Serial.available() == 0)
  {
  }

  input2 = Serial.readString().toInt();
  Serial.println(input2);


  outLeds(input2, 1);

  Serial.println("\nChoose Operation:");
  Serial.println("[1] Addition (RED)");
  Serial.println("[2] Subtraction (GREEN)");
  Serial.print("Choose your operation: ");
  while (Serial.available() == 0) {
  }

  
  op = Serial.readString().toInt();
  Serial.println(op);
  outLeds(op, 2);


  switch (op) {
    case 1:
      result = input1 + input2;
      break;
    case 2:
      result = input1 - input2;
      break;
    default:
      Serial.println("Invalid input.");
  }

  Serial.print("Result : ");
  Serial.println(result);

  resultLeds(result);
}