int BUTTON_1 = 11, BUTTON_2 = 12; // button set ups
int LED_1 = 2, LED_2 = 3, LED_3 = 4, LED_4 = 5; // led set ups
int currentButtonState_1, currentButtonState_2, lastButtonState_1, lastButtonState_2;
int noOfModes = 8, noOfPins = 3; // change every time a pin is added; noOfModes = 2^noOfPins
int modeCounter = 0, ledState = LOW;
int currentDecimal, decimal, binary = 0, remainder, product = 1; // for binary computation

void setup() {
  pinMode(BUTTON_1, INPUT_PULLUP);
  pinMode(BUTTON_2, INPUT_PULLUP);
  pinMode(LED_1, OUTPUT);
  pinMode(LED_2, OUTPUT);
  pinMode(LED_3, OUTPUT);
  pinMode(LED_4, OUTPUT);
  currentButtonState_1 = digitalRead(BUTTON_1);
  currentButtonState_2 = digitalRead(BUTTON_2);
  Serial.begin(115200);
}

void loop() {
  // save last state
  lastButtonState_1 = currentButtonState_1;
  lastButtonState_2 = currentButtonState_2;

  // read new state
  currentButtonState_1 = digitalRead(BUTTON_1);
  currentButtonState_2 = digitalRead(BUTTON_2);

  if (lastButtonState_1 == HIGH && currentButtonState_1 == LOW) {

    // to determine what mode the code currently is in
    if (modeCounter < noOfModes-1) modeCounter++; // -1 because 0 is also a mode
    else if (modeCounter == noOfModes-1) modeCounter = 0;

    // to determine which led will be lighted
    light(modeCounter);

    // print out the current mode
    Serial.print("Mode ");
    Serial.print(modeCounter);
    Serial.println(" activated.");
  }

  if (lastButtonState_2 == HIGH && currentButtonState_2 == LOW) {
    ledState = !ledState;
    digitalWrite(LED_4, ledState);

    if (ledState == LOW) Serial.println("Clockwise activated.");
    else Serial.println("Counter clockwise activated.");
  }
}

int light(int i) {
  for (int j = 1; j <= noOfPins; j++) {
      digitalWrite(j+1, LOW); // all lights will be turned off
  }

  // set & reset values
  currentDecimal = i;
  decimal = i;
  product = 1;
  binary = 0;

  while (decimal != 0) {
    remainder = decimal % 2;
    binary = binary + (remainder * product);
    decimal = decimal / 2;
    product *= 10;

    switch (product) {
      case 10:
        if (remainder == 1) digitalWrite(LED_1, HIGH);
        else digitalWrite(LED_1, LOW);
        break;
       case 100:
        if (remainder == 1) digitalWrite(LED_2, HIGH);
        else digitalWrite(LED_2, LOW);
        break;
       case 1000:
        if (remainder == 1) digitalWrite(LED_3, HIGH);
        else digitalWrite(LED_3, LOW);
        break;
    }
  }

  Serial.print("(");
  Serial.print(binary);
  Serial.print(") ");
}