package com.synthdreams.GalacticBlast;

import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.system.Characters;
import net.rim.device.api.system.Application;
import java.lang.Thread;
import java.lang.Math;
import java.util.*;

// Gameplay extends FullScreen only, it doesn't need the functionality of the
// MainScreen object.  Either are screens though, and can be pushed onto the 
// screen stack
// Special Note: For those familiar with the concept double buffering, supposedly
// the rim UI automatically does this.  It seems to from what I can see, I
// notice no tearing or graphic anomalies.
// For those unfamiliar, if you blit (write) graphic data directly primary graphic
// buffer, it is out of sync with the refresh of the screen.  This can cause
// tearing or other weird graphic issues, as half of the screen is still being shown
// where the objects were, and the other half where the objects are now.  This
// is solved by first drawing to a back buffer, and then flipping the entire
// back buffer with the front during the screen's refresh.  In java there are
// specific game-oriented screen classes to do this, but supposedly the RIM
// libs do this automatically. 
public class GamePlay extends FullScreen
{
    // These three objects are called from many places and are made public
    public static GFX gfx;  // Static object for graphics control
    public static SND snd;  // Static object for sound control
    public static Random rndGenerator; // Static object for random numbers
    
    Refresher _refresher;  // Thread that continually refreshes the game
    EnemyAI _enemyai; // Thread when the enemies think
    Vector _objects; // A vector of all objects currently in play
    
    boolean _active; // Flag if our game is currently active or not (eg did we lose)
    int _score; // Player's current score
    
    // Getters for active and score
    boolean getActive() { return _active; }
    int getScore() {return _score; }
    
    // Refresh is a type of thread that runs to refresh the game.  
    // Its job is to make sure all the processing is called for each object, update the background,
    // update score, check for end of game, etc.  This is the main heartbeat.
    private class Refresher extends Thread
    {
        // When the object is created it starts itself as a thread
        Refresher()
        { 
           start();
        }
        
        // This method defines what this thread does every time it runs.
        public void run()
        {
            // Temporary variable that stores the score value of all
            // the objects that were just cleaned (destroyed/removed)
            // return a negative number if we died
            int cleanReturn;
            
            // This thread runs while the game is active
            while (_active)
            {
                
                // Level population/processing, responsible for creating new enemies
                processLevel();
                
                // Perform physics by calling each object's process command.  Objects
                // are unique and control their own physics (e.g. a photon blast can move
                // faster than our hero ship), so we loop through all our objects
                // and call the process method on each.
                for (int lcv = 0 ; lcv < _objects.size() ; lcv++)
                {
                    ((OBJ) _objects.elementAt(lcv)).process();
                }
                
                // Collision detection of objects.  If they collide, this method
                // will call the damage method of each object, which might lead
                // to no life for the object
                OBJ.collisionDetect(_objects);
                
                // Clean up stuff that's gone (e.g. life of 0 and in 
                // destroyable state, eg explosion graphic), quit if we were destroyed
                cleanReturn = OBJ.cleanObjects(_objects);
                
                // If we didn't die, add the score, redraw, etc.
                if (cleanReturn >= 0)
                {
                   _score += cleanReturn;
                   
                   // Now that all our processing is done, tell the graphics engine to 
                   // redraw the screen through a call to invalidate (invalidates the screen
                   // and automatically causes a redraw)
                   invalidate();
                }
                else
                {
                   // if we died, mark active as false.
                   _active = false;    
                }
                   
                try
                {
                    // Attempt to sleep for 50 ms
                    this.sleep(50);
                        
                }
                catch (InterruptedException e)
                {
                    // Do nothing if we couldn't sleep, we don't care about exactly perfect
                    // timing.
                }
            }
        }
                
    }

    // We have a separate thread that takes care of enemy AI.  This allows us to control how
    // quickly the enemies think outside of our main refresh thread.  That way we can make
    // dumb enemies that think much slower than the action happening around them, or smart
    // enemies that think as fast.
    private class EnemyAI extends Thread
    {
        EnemyAI()
        { 
           start();
           
        }
        
        public void run()
        {
            // Just make sure the thread doesn't accidentally run when the game is over
            while (_active)
            {
                // Loop through all the objects and call the think method, which
                // controls the actions of that object.  Technically, this call's
                // the hero's think method as well, but Hero doesn't have the
                // think method overridden from the parent's, which is just blank,
                // so the hero does no automatic thinking.
                for (int lcv = 0 ; lcv < _objects.size() ; lcv++)
                {
                    if (_active)
                        ((OBJ) _objects.elementAt(lcv)).think(_objects);
                }
                
                try
                {
                    // Enemies think 5 times a second
                    this.sleep(1000/5);
                        
                }
                catch (InterruptedException e)
                {
                    // Do nothing, again we don't care if timing isn't exact
                }
            }

        }
        
    }

    public GamePlay()
    {
        snd = new SND(); // Create sound engine
        gfx = new GFX(); // Create graphics engine
    
        rndGenerator = new Random(); // Create random number generator

        _active = true; // Mark the game as active
        _score = 0; // Start with a score of 0

        // Set our background to stars.png with a speed of 3 pixels per refresh
        gfx.initBackground("stars.jpg", 3);

        // Start our music playing.  Something odd I noticed with my Blackberry 8830,
        // which may either be a bug or some functionality I'm missing from the
        // sound routines, is the volume starts out very quiet the first time you
        // start playing. If you stop the music playing and play it again, the volume
        // is fine.  This might not be true for all Blackberrys, but it doesn't hurt
        // anything to start, stop, and start again, so that's what we've done here,
        // just to solve the volume bug/misundertsanding.
        snd.playMusic("music.mid");
        snd.stopMusic();
        snd.playMusic("music.mid");

        // Create a new vector to hold all the active objects (hero, enemies, photons, etc)
        _objects = new Vector();
        
        // Our hero will always be the very first object in the vector.
        _objects.addElement(new Hero(Graphics.getScreenWidth() / 2, Graphics.getScreenHeight() - 50));
        
        // Create the refresher and enemy AI last, we want to make sure all our objects are setup first
        // so the threads don't make use of uninitialized objects
        _refresher = new Refresher();        
        _enemyai = new EnemyAI();
       
    }
  
    // Process level is responsible for new computer generated events in the game.  In our
    // case, the only one really is creating new enemies.  
    public void processLevel()
    {
        OBJ tempObject;
        
        // Throw a new enemy in every 25 pixels.  This can be made more complex if desired
        // of course
        if (gfx.getBackPos() % 25 == 0)
        {
            // Create a new enemy drone with the X coordinate somewhere between the two edges of the
            // screen
            tempObject = new EnemyDrone(rndGenerator.nextInt() % Graphics.getScreenWidth(), 0);
            
            // Set the Y coordinate to above the screen, so it comes in from the top
            tempObject.setY(tempObject.getY() - tempObject.getBitmap().getHeight() + 3);
            
            // Add the enemy to the object vector
            _objects.addElement(tempObject);    
        }
    }
 
    // This method is called when the invalidate method is called from the refresh thread.
    // We have it passing the graphics object over to our graphics engine so our
    // custom graphics routines can take care of any drawing necessary.
    protected void paint(Graphics graphics)
    { 
       gfx.process(graphics, _objects, _score, ((Hero)_objects.elementAt(0)).getLives()); 
    }
    
    // The keyChar method is called by the event handler when a key is pressed.  
    public boolean keyChar(char key, int status, int time) 
    {
        
        boolean retVal = false;
        
        switch (key)
        {
            // If escape is pressed, we set the game to inactive (quit)
            case Characters.ESCAPE:
                _active = false;
                retVal = true;
                break;
                
            // If the spacebar is pressed, we call the fire method of our
            // hero object, causing him to fire a photon
            case Characters.SPACE:
                ((Hero)_objects.elementAt(0)).fire(_objects);

                retVal = true;
                break;
            
            default:
               break;
        }
                 
        return retVal;
    }
    
    // The navigationMovement method is called by the event handler when the trackball is used. 
    protected boolean navigationMovement(int dx, int dy, int status, int time)
    {
        // If the trackball was scrolled in the horizontal direction, we add that amount to
        // our hero's X velocity
        if (dx != 0)
            ((OBJ)_objects.elementAt(0)).setVelX(dx/Math.abs(dx)*5+((OBJ)_objects.elementAt(0)).getVelX());

        // If the trackball was scrolled in the vertical direction, we add that amount to
        // our hero's Y velocity            
        if (dy != 0)
            ((OBJ)_objects.elementAt(0)).setVelY(dy/Math.abs(dy)*5+((OBJ)_objects.elementAt(0)).getVelY());
            
        return true;
    }
    
}