/*==============================================================================

FILE:  DemoIntro.java

GENERAL DESCRIPTION:
   MIDlet to display introduction for demonstration menu MIDlet.

Copyright (c) 2002 Qualcomm Inc.  All rights reserved.
==============================================================================*/

package com.qualcomm.demo.menu;

import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.*;
import java.lang.*;
import java.util.*;
import com.sun.midp.midlet.Scheduler;
import javax.microedition.media.*;
import javax.microedition.media.control.*;
import com.qualcomm.midp.Main;

/**
 * DemoIntro MIDlet.
 */
public class DemoIntro extends MIDlet implements CommandListener
{
   // MIDlet to instantiate when this MIDlet is done
   private final String MENU_MIDLET = "com.qualcomm.demo.menu.DemoMenu";

   // Number of milliseconds to animate and to wait before going to next MIDlet
   private final int ANIMATION_TIME = 5000;
   private final int TOTAL_TIME = 8000;

   // Number of milliseconds for each animation step
   private final int ANIMATION_STEP_TIME = 30;

   // Horizontal offset of final location of first and second images
   // ("Qualcomm" and "Presents")
   private final int IMAGE_OFFSET_X1 = -20;
   private final int IMAGE_OFFSET_X2 = 0;

   // Vertical space between final location of first two and second two images
   // (after "Qualcomm" and "Presents")
   private final int IMAGE_SPACING_Y1 = 5;
   private final int IMAGE_SPACING_Y2 = 15;

   // Maximum value for animation stepping
   private final int MAX_ANIMATION_STEP = 10;

   // Random number generator
   private Random random = new Random();

   // Animation step number (counts down to 0)
   private int animationStep;

   // Timer tasks to animate screen and wait for demo to finish
   TimerTask animatorTask;
   TimerTask waiterTask;

   // Display for this MIDlet
   private Display display;

   private Player introMusic = null;
   private Control volControl = null;

   // Softkeys for main screen
   private final Command skipCommand =
      new Command("Skip", Command.SCREEN, 1);
   private final Command exitCommand =
      new Command("Exit", Command.EXIT, 1);

   // Main screen and initialization code
   private final Canvas screen = new Canvas()
   {
      // Height of all 3 images plus space in between
      // (assume screen is big enough for this)
      private final int totalImageHeight =
         qualcommImg.getHeight() + IMAGE_SPACING_Y1 +
         presentsImg.getHeight() + IMAGE_SPACING_Y1 +
         javaImg.getHeight();

      // Image display final X-positions
      private final int qualcommX =
         ((getWidth() - qualcommImg.getWidth()) / 2) + IMAGE_OFFSET_X1;
      private final int presentsX =
         ((getWidth() - presentsImg.getWidth()) / 2) + IMAGE_OFFSET_X2;
      private final int javaX =
         (getWidth() - javaImg.getWidth()) / 2;

      // Image display final Y-positions
      private final int qualcommY =
         (getHeight() - totalImageHeight) / 2;
      private final int presentsY =
         qualcommY + qualcommImg.getHeight() + IMAGE_SPACING_Y1;
      private final int javaY =
         presentsY + presentsImg.getHeight() + IMAGE_SPACING_Y2;

      // Images with final positions
      private final MovingImage qualcomm =
         new MovingImage(qualcommImg, qualcommX, qualcommY);
      private final MovingImage presents =
         new MovingImage(presentsImg, presentsX, presentsY);
      private final MovingImage java =
         new MovingImage(javaImg, javaX, javaY);

      // Class to represent moving image
      class MovingImage
      {
         // Image and final position
         private Image image;
         private int finalX;
         private int finalY;

         // Animation step values
         private int stepX = randomAnimationStep();
         private int stepY = randomAnimationStep();

         // Constructor
         MovingImage(Image image, int finalX, int finalY)
         {
            this.image = image;
            this.finalX = finalX;
            this.finalY = finalY;
         }

         // Returns random animation step value
         private int randomAnimationStep()
         {
            // Get random number between 1 and MAX_ANIMATION_STEP (inclusive)
            int i = ((random.nextInt() & 0x7fffffff) % MAX_ANIMATION_STEP) + 1;

            // Return positive or negative number
            return ((random.nextInt() >= 0) ? i : -i);
         }

         // Converts a virtual X or Y position (which is where the image would
         // be if the movement wasn't confined to the screen) to an actual X or
         // Y position, given the effective X or Y screen dimension (which is
         // the actual X or Y screen dimension minus the X or Y image dimension)
         private int convertPos(int pos, int dim)
         {
            // Convert position to equivalent number between 0 and (dim * 2)
            if (pos < 0)
            {
               pos = -pos;
            }
            pos %= (dim * 2);

            // If position between dim and (dim * 2), convert to go from other
            // direction
            if (pos >= dim)
            {
               pos = (dim * 2) - 1 - pos;
            }

            return pos;
         }

         // Draws the image in the position specified by the given step
         public void draw(Graphics g, int step)
         {
            int x = convertPos(finalX - (step * stepX),
                               (getWidth() - image.getWidth()));
            int y = convertPos(finalY - (step * stepY),
                               (getHeight() - image.getHeight()));

            g.drawImage(image, x, y, Graphics.TOP | Graphics.LEFT);
         }
      }

      // Paints the screen
      protected void paint(Graphics g)
      {
         // Clear screen to white
         g.setColor(0xffffff);
         g.fillRect(0, 0, getWidth(), getHeight());

         // Draw first two images ("qualcomm" will go on top if overlapping)
         presents.draw(g, animationStep);
         qualcomm.draw(g, animationStep);

         // Draw "java" image only when animation complete
         if (animationStep == 0)
         {
            java.draw(g, 0);
         }
      }
   };
   {
      // Configure softkeys
      screen.addCommand(skipCommand);
      screen.addCommand(exitCommand);
      screen.setCommandListener(this);
   }

   // Schedules menu MIDlet in place of this MIDlet
   private void scheduleMenuMidlet()
   {
      // Instead of instantiating the menu MIDlet while demoIntro is 
      // still active, we will restart KVM to run menu MIDlet. This 
      // can prevent the case that when garbage collection needs to be
      // kicked in to reclaim free memory for the newly-instantiated 
      // MIDlet and at the same time an asynchronous funciton is active.
      // This would cause the applicaiton to hang.
      Main.registerStartApp(MENU_MIDLET, null);   
      /* 
      // Exit this app
    
      // Try to instantiate new midlet
      try
      {
         Scheduler.getScheduler().scheduleMIDlet(
            (MIDlet)(Class.forName(MENU_MIDLET).newInstance()));
      }
      catch (Exception e)
      {
         // Create an error message
         String errorString =
            "Could not instantiate " + MENU_MIDLET + "\n" + e.toString();

         // Create an "error" screen containing error message
         Form errorScreen = new Form("Fatal Error");
         errorScreen.append(errorString);