package dtmgame;

import java.awt.Graphics;
import java.awt.Point;

/**
 * @author Shaohan Hu
 * 
 */
public class CircleParticle {
    private static final long serialVersionUID = 1L;
    private int x, y;
    private int r;
    private int vx, vy;
    private int left, right, top, bottom;

    private int rvx, rvy;
    private int randomMagnitude = 1;

    public CircleParticle(int x, int y, int r, int vx, int vy, int left,
			  int right, int top, int bottom) {
	this.x = x;
	this.y = y;
	this.r = r;
	this.vx = vx;
	this.vy = vy;
	this.left = left;
	this.right = right;
	this.top = top;
	this.bottom = bottom;
    }

    public Point getPosition() {
	return new Point(x, y);
    }

    public void takeOneStep() {
	x += (vx + rvx);
	y += (vy + rvy);
	this.updateDirections();
    }

    public void updateDirections() {
	if (Math.random() >= 0.5) {
	    rvx = randomMagnitude;
	} else {
	    rvx = randomMagnitude * (-1);
	}

	if (Math.random() >= 0.5) {
	    rvy = 3;
	} else {
	    rvy = randomMagnitude * (-1);
	}

	if (x + vx + rvx <= left || x + vx + rvx >= right) {
	    vx += rvx;
	    vx *= -1;
	}

	if (y + vy <= top || y + vy >= bottom) {
	    vy += rvy;
	    vy *= -1;
	}
    }

    public void drawParticle(Graphics g) {
	g.fillOval(x - r, y - r, 2 * r, 2 * r);
    }
}