/**
  *Velocity is the speed and direction of a moving object
  *@author John D. McGregor
  *@version 1.0
  */
class Velocity{
	protected int xSpeed;
	protected int ySpeed;
	protected int speed;
	protected int direction;

	/**
	  *Default Constructor initializes all attributes to zero
    *pre: must have at least 16 bytes free before calling constructor
	  */
	public Velocity(){
		xSpeed = 0;
		ySpeed = 0;
		speed = 0;
		direction = 0;
	}

	/**
	  *Constructor
	  *@param newSpeed     Defines the initial speed
	  *@param newDirection Defines the initial direction
    *pre: must have at least 16 bytes free before calling constructor
	  */
	public Velocity(int newSpeed,int newDirection){
		direction = newDirection;
		this.setSpeed(newSpeed);
		decomposeSpeed();
	}

	/**
	  *reverses the meaning of the X component of velocity
	  */
	public void reverseX(){
		xSpeed = - xSpeed;
		if(direction < 180){
			direction = 180 - direction;
		}
		else{
			direction = 540 - direction;
		}
	}
	
	/**
	  *reverses the meaning of the Y component of velocity
	  */
	public void reverseY(){
		ySpeed = - ySpeed;
		direction = (360 - direction)% 360;
	}

	/**
	  *Setter for speed
	  *Also sets XSpeed and YSpeed
	  */
	public void setSpeed(int newSpeed){
		speed = newSpeed;
		decomposeSpeed();
	}

	/**
	  *Setter for the direction
	  *post: direction>=0 && direction<=360
	  */
	public void setDirection(int newDirection){
		direction = newDirection % 360;
	}

	/**
	  *Simple accessor for direction
	  */
	public int getDirection(){
		return direction;
	}

	/**
	  *Simple accessor for X component of speed
	  */
	public int getSpeedX(){
		return xSpeed;
	}

	/**
	  *Simple accessor for Y component of speed
	  */
	public int getSpeedY(){
		return ySpeed;
	}


  public boolean isHeadingUp(){

    if(direction > 0 && direction < 180){

      return true;

    }else{

      return false;

    }

  }

	/**
	  *Creates the X and Y components of the speed
	  *Should be called every time speed is set
	  */
	void decomposeSpeed(){
		xSpeed = (int)(Math.cos(direction/57.9)*speed);
		ySpeed = (int)(Math.sin(direction/57.9)*speed);
	}
}