package G1.particles_moving;

import java.awt.Canvas;
import java.awt.Graphics;
import java.util.Random;

import javax.swing.JApplet;

/* Osnovne skracenice (shortcuts):
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 * ctrl+shift+F = Autoformat
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 * 
 */

public class ParticleApplet extends JApplet {

	public ParticleApplet() {

	}

	@Override
	public void init() {
		// TODO Auto-generated method stub
		super.init();
		setSize(500, 500);
		add(new ParticleCanvas(1000));
	}
}

class ParticleCanvas extends Canvas {
	private Random randGen = new Random();
	private Particle[] particles;

	public ParticleCanvas(int n) {
		setSize(500, 500);
		particles = new Particle[n];
		for (int i = 0; i < n; i++)
			particles[i] = new Particle(randGen.nextInt(500),
					randGen.nextInt(500), this);
		// pokretanje niti, nakon cega nit pocinje da izvrsava svoj run metod
		for (Particle p : particles)
			p.start();
	}

	@Override
	public void paint(Graphics g) {
		super.paint(g);
		for (Particle p : particles) {
			g.fillOval(p.getX(), p.getY(), 5, 5);
		}
	}
}

class Particle extends Thread {
	private int x;
	private int y;
	private ParticleCanvas canvas;

	public Particle(int x, int y, ParticleCanvas canvas) {
		super();
		this.canvas=canvas;
		this.x = x;
		this.y = y;
	}

	public int getX() {
		return x;
	}

	public int getY() {
		return y;
	}

	private void move() {
		double rvx = Math.random();
		double rvy = Math.random();
		if (rvx < 0.33)
			x -= 1;
		else if (rvx > 0.66)
			x += 1;
		if (rvy < 0.33)
			y -= 1;
		else if (rvy > 0.66)
			y += 1;
	}

	@Override
	public void run() {
		while (true) {
			move();
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			canvas.repaint();
		}
	}
}