/*
 * @(#)ManyCanvas.java	1.8 00/08/03
 * Copyright (c) 1999,2000 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */

package example.manyballs;

import javax.microedition.lcdui.*;


public class ManyCanvas extends javax.microedition.lcdui.Canvas {

    Display display;

    // a set of free roaming balls
    SmallBall[] balls;
    int numBalls;
    int width, height;
    boolean paused;

    public ManyCanvas(Display d, int maxBalls) {

	display = d;		// save the display

	// initialize the array of balls
	balls = new SmallBall[maxBalls];
	
	width = getWidth();
	height = getHeight();

	// Start with one ball
	balls[0] = new SmallBall(this, 0, 0,width,height-12);
	numBalls = 1;
	paused = true;
    }

    /**
     * Draws the drawing frame (which also contains the ball) and the
     * controls.
     */
    protected void paint(Graphics g) {
	// Draw the frame 
	g.setColor(0xffffff);
	g.fillRect(0,0, width-1, height-1);
	g.setColor(0);
	g.drawRect(0+1,0+1,width-2,height-2);

	// Draw each ball
	for(int i = 0; i < numBalls; i++) {
	    balls[i].paint(g);
	}
	
	g.drawString(numBalls + " Balls", 5, height-14, 0);
    }

    /**
     * Handle a pen down event.
     */
    public void keyPressed( int keyCode) {

	int action = getGameAction(keyCode);

	switch (action) {
	case LEFT:
	    // Reduce the number of threads
	    if (numBalls > 0) {

		// decrement the counter
		numBalls = numBalls - 1;

		// stop the thread and remove the reference to it
		balls[numBalls].stop = true;
		balls[numBalls] = null;
	    }
	    break;

	case RIGHT:
	    // Increase the number of threads
	    if (numBalls < balls.length) {

		// create a new ball and start it moving
		balls[numBalls] = new SmallBall(this, 0, 0, width,height-12);
		new Thread(balls[numBalls]).start();

		// increment the counter
		numBalls = numBalls + 1;
	    }
	    break;

	case UP:
	    // Make them move faster
	    SmallBall.faster();
	    break;

	case DOWN:
	    // Make them move slower
	    SmallBall.slower();
	    break;
	}
	repaint();
    }

    /**
     * Destroy
     */
    void destroy() {
	// kill all the balls and terminate
	for (int i = 0; i < balls.length && balls[i] != null; i++) {
	    balls[i].stop = true;

	    // enable the balls to be garbage collected
	    balls[i] = null;
	}
	numBalls = 0;
    }


    /*
     * Return whether the canvas is paused or not.
     */
    boolean isPaused() {
	return paused;
    }

    /**
     * Pause the balls by signaling each of them to stop.
     * The ball object still exists and holds the current position
     * of the ball.  It may be restarted later.
     * The thread will terminate.
     * TBD: is a join needed?
     */
    void pause() {
	if (!paused) {
	    paused = true;
	    for (int i = 0; i < balls.length && balls[i] != null; i++) {
		balls[i].stop = true;
	    }
	}
	repaint();
    }

    /*
     * Start creates a new thread for each ball and start it.
     */
    void start() {
	if (paused) {
	    paused = false;
	    display.setCurrent(this);
	    for (int i = 0; i < balls.length && balls[i] != null; i++) {
		Thread t = new Thread(balls[i]);
		t.start();
	    }
	}
	repaint();
    }
	

}