#define IN1 2
#define IN2 3
#define IN3 4
#define IN4 5
#define RED_LED 6
#define WHITE_LED 7
#define GREEN_LED 8
#define MULTI_COLOURED_LED 9
#define YELLOW_LED 10
#define BLUE_LED 11

bool ledState = false;

void setup() {
  Serial.begin(9600);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(WHITE_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(MULTI_COLOURED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(BLUE_LED, OUTPUT);
  pinMode(A1, OUTPUT);
}

void loop() {
  if (Serial.available() > 0) {
    char value = Serial.read();
    Serial.println(value);

    if (value == 'U') {
      Forward();
    } else if (value == 'D') {
      if (Serial.available() > 0) {
        char nextChar = Serial.read();
        if (nextChar == 'L') {
          ledState = !ledState;
          digitalWrite(A1, ledState ? HIGH : LOW);
        }
      }
    } else if (value == 'S') {
      Stop();
    } else if (value == 'L') {
      Left();
    } else if (value == 'R') {
      Right();
    } else if (value == '1') {
      digitalWrite(RED_LED, HIGH);
    } else if (value == '2') {
      digitalWrite(RED_LED, LOW);
    } else if (value == '3') {
      digitalWrite(WHITE_LED, HIGH);
    } else if (value == '4') {
      digitalWrite(WHITE_LED, LOW);
    } else if (value == '5') {
      digitalWrite(GREEN_LED, HIGH);
    } else if (value == '6') {
      digitalWrite(GREEN_LED, LOW);
    } else if (value == '7') {
      digitalWrite(MULTI_COLOURED_LED, HIGH);
    } else if (value == '8') {
      digitalWrite(MULTI_COLOURED_LED, LOW);
    } else if (value == '9') {
      digitalWrite(YELLOW_LED, HIGH);
    } else if (value == '0') {
      digitalWrite(YELLOW_LED, LOW);
    } else if (value == 'q') {
      digitalWrite(BLUE_LED, HIGH);
    } else if (value == 'w') {
      digitalWrite(BLUE_LED, LOW);
    } else {
      Serial.println("Invalid command");
    }
  }
}

void Forward() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void Backward() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void Stop() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
}

void Left() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void Right() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}