package android.opengl;

import java.io.Writer;
import java.util.ArrayList;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGL11;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.egl.EGLSurface;
import javax.microedition.khronos.opengles.GL;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.BaseConfigChooser.ComponentSizeChooser;
import android.opengl.BaseConfigChooser.SimpleEGLConfigChooser;
import android.service.wallpaper.WallpaperService;
import android.util.Log;
import android.view.SurfaceHolder;

public class GLWallpaperService extends WallpaperService
{
	private static final String TAG = "GLWallpaperService";

	@Override
	public Engine onCreateEngine()
	{
		return new GLEngine();
	}

	public class GLEngine extends Engine
	{
		public final static int RENDERMODE_WHEN_DIRTY = 0;
		public final static int RENDERMODE_CONTINUOUSLY = 1;

		private GLThread mGLThread;
		private EGLConfigChooser mEGLConfigChooser;
		private EGLContextFactory mEGLContextFactory;
		private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
		private GLWrapper mGLWrapper;
		private int mDebugFlags;

		public GLEngine()
		{
			super();
		}

		@Override
		public void onVisibilityChanged(boolean visible)
		{
			if (visible)
			{
				onResume();
			}
			else
			{
				onPause();
			}
			super.onVisibilityChanged(visible);
		}

		@Override
		public void onCreate(SurfaceHolder surfaceHolder)
		{
			super.onCreate(surfaceHolder);
			// Log.d(TAG, "GLEngine.onCreate()");
		}

		@Override
		public void onDestroy()
		{
			super.onDestroy();
			// Log.d(TAG, "GLEngine.onDestroy()");
			mGLThread.requestExitAndWait();
		}

		@Override
		public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height)
		{
			// Log.d(TAG, "onSurfaceChanged()");
			mGLThread.onWindowResize(width, height);
			super.onSurfaceChanged(holder, format, width, height);
		}

		@Override
		public void onSurfaceCreated(SurfaceHolder holder)
		{
			//Log.d(TAG, "onSurfaceCreated()");
			mGLThread.surfaceCreated(holder);
			super.onSurfaceCreated(holder);
		}

		@Override
		public void onSurfaceDestroyed(SurfaceHolder holder)
		{
			//Log.d(TAG, "onSurfaceDestroyed()");
			mGLThread.surfaceDestroyed();
			super.onSurfaceDestroyed(holder);
		}

		/**
		 * An EGL helper class.
		 */
		public void setGLWrapper(GLWrapper glWrapper)
		{
			mGLWrapper = glWrapper;
		}

		public void setDebugFlags(int debugFlags)
		{
			mDebugFlags = debugFlags;
		}

		public int getDebugFlags()
		{
			return mDebugFlags;
		}

		public void setRenderer(Renderer renderer)
		{
			checkRenderThreadState();
			if (mEGLConfigChooser == null)
			{
				mEGLConfigChooser = new SimpleEGLConfigChooser(true);
			}
			if (mEGLContextFactory == null)
			{
				mEGLContextFactory = new DefaultContextFactory();
			}
			if (mEGLWindowSurfaceFactory == null)
			{
				mEGLWindowSurfaceFactory = new DefaultWindowSurfaceFactory();
			}
			mGLThread = new GLThread(renderer, mEGLConfigChooser, mEGLContextFactory, mEGLWindowSurfaceFactory, mGLWrapper);
			mGLThread.start();
		}

		public void setEGLContextFactory(EGLContextFactory factory)
		{
			checkRenderThreadState();
			mEGLContextFactory = factory;
		}

		public void setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory factory)
		{
			checkRenderThreadState();
			mEGLWindowSurfaceFactory = factory;
		}

		public void setEGLConfigChooser(EGLConfigChooser configChooser)
		{
			checkRenderThreadState();
			mEGLConfigChooser = configChooser;
		}

		public void setEGLConfigChooser(boolean needDepth)
		{
			setEGLConfigChooser(new SimpleEGLConfigChooser(needDepth));
		}

		public void setEGLConfigChooser(int redSize, int greenSize, int blueSize, int alphaSize, int depthSize, int stencilSize)
		{
			setEGLConfigChooser(new ComponentSizeChooser(redSize, greenSize, blueSize, alphaSize, depthSize, stencilSize));
		}

		public void setRenderMode(int renderMode)
		{
			mGLThread.setRenderMode(renderMode);
		}

		public int getRenderMode()
		{
			return mGLThread.getRenderMode();
		}

		public void requestRender()
		{
			mGLThread.requestRender();
		}

		public void onPause()
		{
			mGLThread.onPause();
		}

		public void onResume()
		{
			mGLThread.onResume();
		}

		public void queueEvent(Runnable r)
		{
			mGLThread.queueEvent(r);
		}

		private void checkRenderThreadState()
		{
			if (mGLThread != null)
			{
				throw new IllegalStateException("setRenderer has already been called for this instance.");
			}
		}
	}

	public interface Renderer
	{

		public void onSurfaceCreated(GL10 gl, EGLConfig config);

		public void onSurfaceChanged(GL10 gl, int width, int height);

		public void onDrawFrame(GL10 gl);
	}
}

class LogWriter extends Writer
{
	private StringBuilder mBuilder = new StringBuilder();

	@Override
	public void close()
	{
		flushBuilder();
	}

	@Override
	public void flush()
	{
		flushBuilder();
	}

	@Override
	public void write(char[] buf, int offset, int count)
	{
		for (int i = 0; i < count; i++)
		{
			char c = buf[offset + i];
			if (c == '\n')
			{
				flushBuilder();
			}
			else
			{
				mBuilder.append(c);
			}
		}
	}

	private void flushBuilder()
	{
		if (mBuilder.length() > 0)
		{
			Log.v("GLSurfaceView", mBuilder.toString());
			mBuilder.delete(0, mBuilder.length());
		}
	}
}

// ----------------------------------------------------------------------

/**
 * An interface for customizing the eglCreateContext and eglDestroyContext
 * calls.
 * 
 * 
 * This interface must be implemented by clients wishing to call
 * {@link GLWallpaperService#setEGLContextFactory(EGLContextFactory)}
 */
interface EGLContextFactory
{
	EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig);

	void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context);
}

class DefaultContextFactory implements EGLContextFactory
{

	public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig config)
	{
		return egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT, null);
	}

	public void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context)
	{
		egl.eglDestroyContext(display, context);
	}
}

/**
 * An interface for customizing the eglCreateWindowSurface and eglDestroySurface
 * calls.
 * 
 * 
 * This interface must be implemented by clients wishing to call
 * {@link GLWallpaperService#setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory)}
 */
interface EGLWindowSurfaceFactory
{
	EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config, Object nativeWindow);

	void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface);
}

class DefaultWindowSurfaceFactory implements EGLWindowSurfaceFactory
{

	public EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config, Object nativeWindow)
	{
		// this is a bit of a hack to work around Droid init problems - if you
		// don't have this, it'll get hung up on orientation changes
		EGLSurface eglSurface = null;
		while (eglSurface == null)
		{
			try
			{
				eglSurface = egl.eglCreateWindowSurface(display, config, nativeWindow, null);
			} catch (Throwable t)
			{
			} finally
			{
				if (eglSurface == null)
				{
					try
					{
						Thread.sleep(10);
					} catch (InterruptedException t)
					{
					}
				}
			}
		}
		return eglSurface;
	}

	public void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface)
	{
		egl.eglDestroySurface(display, surface);
	}
}

interface GLWrapper
{
	/**
	 * Wraps a gl interface in another gl interface.
	 * 
	 * @param gl
	 *            a GL interface that is to be wrapped.
	 * @return either the input argument or another GL object that wraps the
	 *         input argument.
	 */
	GL wrap(GL gl);
}

class EglHelper
{

	private EGL10 mEgl;
	private EGLDisplay mEglDisplay;
	private EGLSurface mEglSurface;
	private EGLContext mEglContext;
	EGLConfig mEglConfig;

	private EGLConfigChooser mEGLConfigChooser;
	private EGLContextFactory mEGLContextFactory;
	private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
	private GLWrapper mGLWrapper;

	public EglHelper(EGLConfigChooser chooser, EGLContextFactory contextFactory, EGLWindowSurfaceFactory surfaceFactory, GLWrapper wrapper)
	{
		this.mEGLConfigChooser = chooser;
		this.mEGLContextFactory = contextFactory;
		this.mEGLWindowSurfaceFactory = surfaceFactory;
		this.mGLWrapper = wrapper;
	}

	/**
	 * Initialize EGL for a given configuration spec.
	 * 
	 * @param configSpec
	 */
	public void start()
	{

		if (mEgl == null)
		{

			/*
			 * Get an EGL instance
			 */
			mEgl = (EGL10) EGLContext.getEGL();
		}
		else
		{

		}

		if (mEglDisplay == null)
		{

			/*
			 * Get to the default display.
			 */
			mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
		}
		else
		{

		}

		if (mEglConfig == null)
		{

			/*
			 * We can now initialize EGL for that display
			 */
			int[] version = new int[2];
			mEgl.eglInitialize(mEglDisplay, version);
			mEglConfig = mEGLConfigChooser.chooseConfig(mEgl, mEglDisplay);
		}
		else
		{

		}

		if (mEglContext == null)
		{

			/*
			 * Create an OpenGL ES context. This must be done only once, an
			 * OpenGL context is a somewhat heavy object.
			 */
			mEglContext = mEGLContextFactory.createContext(mEgl, mEglDisplay, mEglConfig);
			if (mEglContext == null || mEglContext == EGL10.EGL_NO_CONTEXT)
			{
				throw new RuntimeException("createContext failed");
			}
		}
		else
		{

		}

		mEglSurface = null;
	}

	/*
	 * React to the creation of a new surface by creating and returning an
	 * OpenGL interface that renders to that surface.
	 */
	public GL createSurface(SurfaceHolder holder)
	{
		/*
		 * The window size has changed, so we need to create a new surface.
		 */
		if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE)
		{

			/*
			 * Unbind and destroy the old EGL surface, if there is one.
			 */
			mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT);
			mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
		}

		/*
		 * Create an EGL surface we can render into.
		 */
		mEglSurface = mEGLWindowSurfaceFactory.createWindowSurface(mEgl, mEglDisplay, mEglConfig, holder);

		if (mEglSurface == null || mEglSurface == EGL10.EGL_NO_SURFACE)
		{
			throw new RuntimeException("createWindowSurface failed");
		}

		/*
		 * Before we can issue GL commands, we need to make sure the context is
		 * current and bound to a surface.
		 */
		if (!mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext))
		{
			throw new RuntimeException("eglMakeCurrent failed.");
		}

		GL gl = mEglContext.getGL();
		if (mGLWrapper != null)
		{
			gl = mGLWrapper.wrap(gl);
		}

		/*
		 * if ((mDebugFlags & (DEBUG_CHECK_GL_ERROR | DEBUG_LOG_GL_CALLS))!= 0)
		 * { int configFlags = 0; Writer log = null; if ((mDebugFlags &
		 * DEBUG_CHECK_GL_ERROR) != 0) { configFlags |=
		 * GLDebugHelper.CONFIG_CHECK_GL_ERROR; } if ((mDebugFlags &
		 * DEBUG_LOG_GL_CALLS) != 0) { log = new LogWriter(); } gl =
		 * GLDebugHelper.wrap(gl, configFlags, log); }
		 */
		return gl;
	}

	/**
	 * Display the current render surface.
	 * 
	 * @return false if the context has been lost.
	 */
	public boolean swap()
	{
		mEgl.eglSwapBuffers(mEglDisplay, mEglSurface);

		/*
		 * Always check for EGL_CONTEXT_LOST, which means the context and all
		 * associated data were lost (For instance because the device went to
		 * sleep). We need to sleep until we get a new surface.
		 */
		return mEgl.eglGetError() != EGL11.EGL_CONTEXT_LOST;
	}

	public void destroySurface()
	{
		if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE)
		{
			mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT);
			mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
			mEglSurface = null;
		}
	}

	public void finish()
	{
		if (mEglContext != null)
		{
			mEGLContextFactory.destroyContext(mEgl, mEglDisplay, mEglContext);
			mEglContext = null;
		}
		if (mEglDisplay != null)
		{
			mEgl.eglTerminate(mEglDisplay);
			mEglDisplay = null;
		}
	}
}

class GLThread extends Thread
{
	private final static boolean LOG_THREADS = false;
	public final static int DEBUG_CHECK_GL_ERROR = 1;
	public final static int DEBUG_LOG_GL_CALLS = 2;

	private final GLThreadManager sGLThreadManager = new GLThreadManager();
	private GLThread mEglOwner;

	private EGLConfigChooser mEGLConfigChooser;
	private EGLContextFactory mEGLContextFactory;
	private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
	private GLWrapper mGLWrapper;

	public SurfaceHolder mHolder;
	private boolean mSizeChanged = true;

	// Once the thread is started, all accesses to the following member
	// variables are protected by the sGLThreadManager monitor
	public boolean mDone;
	private boolean mPaused;
	private boolean mHasSurface;
	private boolean mWaitingForSurface;
	private boolean mHaveEgl;
	private int mWidth;
	private int mHeight;
	private int mRenderMode;
	private boolean mRequestRender;
	private boolean mEventsWaiting;
	// End of member variables protected by the sGLThreadManager monitor.

	private GLWallpaperService.Renderer mRenderer;
	private ArrayList mEventQueue = new ArrayList();
	private EglHelper mEglHelper;

	GLThread(GLWallpaperService.Renderer renderer, EGLConfigChooser chooser, EGLContextFactory contextFactory, EGLWindowSurfaceFactory surfaceFactory, GLWrapper wrapper)
	{
		super();
		mDone = false;
		mWidth = 0;
		mHeight = 0;
		mRequestRender = true;
		mRenderMode = GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY;
		mRenderer = renderer;
		this.mEGLConfigChooser = chooser;
		this.mEGLContextFactory = contextFactory;
		this.mEGLWindowSurfaceFactory = surfaceFactory;
		this.mGLWrapper = wrapper;
	}

	@Override
	public void run()
	{
		setName("GLThread " + getId());
		if (LOG_THREADS)
		{
			Log.i("GLThread", "starting tid=" + getId());
		}

		try
		{
			guardedRun();
		} catch (InterruptedException e)
		{
			// fall thru and exit normally
		} finally
		{
			sGLThreadManager.threadExiting(this);
		}
	}

	/*
	 * This private method should only be called inside a
	 * synchronized(sGLThreadManager) block.
	 */
	private void stopEglLocked()
	{
		if (mHaveEgl)
		{
			mHaveEgl = false;
			mEglHelper.destroySurface();
			sGLThreadManager.releaseEglSurface(this);
		}
	}

	private void guardedRun() throws InterruptedException
	{
		mEglHelper = new EglHelper(mEGLConfigChooser, mEGLContextFactory, mEGLWindowSurfaceFactory, mGLWrapper);
		try
		{
			GL10 gl = null;
			boolean tellRendererSurfaceCreated = true;
			boolean tellRendererSurfaceChanged = true;

			/*
			 * This is our main activity thread's loop, we go until asked to
			 * quit.
			 */
			while (!isDone())
			{
				/*
				 * Update the asynchronous state (window size)
				 */
				int w = 0;
				int h = 0;
				boolean changed = false;
				boolean needStart = false;
				boolean eventsWaiting = false;

				synchronized (sGLThreadManager)
				{
					while (true)
					{
						// Manage acquiring and releasing the SurfaceView
						// surface and the EGL surface.
						if (mPaused)
						{
							stopEglLocked();
						}
						if (!mHasSurface)
						{
							if (!mWaitingForSurface)
							{
								stopEglLocked();
								mWaitingForSurface = true;
								sGLThreadManager.notifyAll();
							}
						}
						else
						{
							if (!mHaveEgl)
							{
								if (sGLThreadManager.tryAcquireEglSurface(this))
								{
									mHaveEgl = true;
									mEglHelper.start();
									mRequestRender = true;
									needStart = true;
								}
							}
						}

						// Check if we need to wait. If not, update any state
						// that needs to be updated, copy any state that
						// needs to be copied, and use "break" to exit the
						// wait loop.

						if (mDone)
						{
							return;
						}

						if (mEventsWaiting)
						{
							eventsWaiting = true;
							mEventsWaiting = false;
							break;
						}

						if ((!mPaused) && mHasSurface && mHaveEgl && (mWidth > 0) && (mHeight > 0) && (mRequestRender || (mRenderMode == GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY)))
						{
							changed = mSizeChanged;
							w = mWidth;
							h = mHeight;
							mSizeChanged = false;
							mRequestRender = false;
							if (mHasSurface && mWaitingForSurface)
							{
								changed = true;
								mWaitingForSurface = false;
								sGLThreadManager.notifyAll();
							}
							break;
						}

						// By design, this is the only place where we wait().

						if (LOG_THREADS)
						{
							Log.i("GLThread", "waiting tid=" + getId());
						}
						sGLThreadManager.wait();
					}
				} // end of synchronized(sGLThreadManager)

				/*
				 * Handle queued events
				 */
				if (eventsWaiting)
				{
					Runnable r;
					while ((r = getEvent()) != null)
					{
						r.run();
						if (isDone())
						{
							return;
						}
					}
					// Go back and see if we need to wait to render.
					continue;
				}

				if (needStart)
				{
					tellRendererSurfaceCreated = true;
					changed = true;
				}
				if (changed)
				{
					gl = (GL10) mEglHelper.createSurface(mHolder);
					tellRendererSurfaceChanged = true;
				}
				if (tellRendererSurfaceCreated)
				{
					mRenderer.onSurfaceCreated(gl, mEglHelper.mEglConfig);
					tellRendererSurfaceCreated = false;
				}
				if (tellRendererSurfaceChanged)
				{
					mRenderer.onSurfaceChanged(gl, w, h);
					tellRendererSurfaceChanged = false;
				}
				if ((w > 0) && (h > 0))
				{
					/* draw a frame here */
					mRenderer.onDrawFrame(gl);

					/*
					 * Once we're done with GL, we need to call swapBuffers() to
					 * instruct the system to display the rendered frame
					 */
					mEglHelper.swap();
				}
			}
		} finally
		{
			/*
			 * clean-up everything...
			 */
			synchronized (sGLThreadManager)
			{
				stopEglLocked();
				mEglHelper.finish();
			}
		}
	}

	private boolean isDone()
	{
		synchronized (sGLThreadManager)
		{
			return mDone;
		}
	}

	public void setRenderMode(int renderMode)
	{
		if (!((GLWallpaperService.GLEngine.RENDERMODE_WHEN_DIRTY <= renderMode) && (renderMode <= GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY)))
		{
			throw new IllegalArgumentException("renderMode");
		}
		synchronized (sGLThreadManager)
		{
			mRenderMode = renderMode;
			if (renderMode == GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY)
			{
				sGLThreadManager.notifyAll();
			}
		}
	}

	public int getRenderMode()
	{
		synchronized (sGLThreadManager)
		{
			return mRenderMode;
		}
	}

	public void requestRender()
	{
		synchronized (sGLThreadManager)
		{
			mRequestRender = true;
			sGLThreadManager.notifyAll();
		}
	}

	public void surfaceCreated(SurfaceHolder holder)
	{
		mHolder = holder;
		synchronized (sGLThreadManager)
		{
			if (LOG_THREADS)
			{
				Log.i("GLThread", "surfaceCreated tid=" + getId());
			}
			mHasSurface = true;
			sGLThreadManager.notifyAll();
		}
	}

	public void surfaceDestroyed()
	{
		synchronized (sGLThreadManager)
		{
			if (LOG_THREADS)
			{
				Log.i("GLThread", "surfaceDestroyed tid=" + getId());
			}
			mHasSurface = false;
			sGLThreadManager.notifyAll();
			while (!mWaitingForSurface && isAlive() && !mDone)
			{
				try
				{
					sGLThreadManager.wait();
				} catch (InterruptedException e)
				{
					Thread.currentThread().interrupt();
				}
			}
		}
	}

	public void onPause()
	{
		synchronized (sGLThreadManager)
		{
			mPaused = true;
			sGLThreadManager.notifyAll();
		}
	}

	public void onResume()
	{
		synchronized (sGLThreadManager)
		{
			mPaused = false;
			mRequestRender = true;
			sGLThreadManager.notifyAll();
		}
	}

	public void onWindowResize(int w, int h)
	{
		synchronized (sGLThreadManager)
		{
			mWidth = w;
			mHeight = h;
			mSizeChanged = true;
			sGLThreadManager.notifyAll();
		}
	}

	public void requestExitAndWait()
	{
		// don't call this from GLThread thread or it is a guaranteed
		// deadlock!
		synchronized (sGLThreadManager)
		{
			mDone = true;
			sGLThreadManager.notifyAll();
		}
		try
		{
			join();
		} catch (InterruptedException ex)
		{
			Thread.currentThread().interrupt();
		}
	}

	/**
	 * Queue an "event" to be run on the GL rendering thread.
	 * 
	 * @param r
	 *            the runnable to be run on the GL rendering thread.
	 */
	public void queueEvent(Runnable r)
	{
		synchronized (this)
		{
			mEventQueue.add(r);
			synchronized (sGLThreadManager)
			{
				mEventsWaiting = true;
				sGLThreadManager.notifyAll();
			}
		}
	}

	private Runnable getEvent()
	{
		synchronized (this)
		{
			if (mEventQueue.size() > 0)
			{
				return (Runnable) mEventQueue.remove(0);
			}

		}
		return null;
	}

	private class GLThreadManager
	{

		public synchronized void threadExiting(GLThread thread)
		{
			if (LOG_THREADS)
			{
				Log.i("GLThread", "exiting tid=" + thread.getId());
			}
			thread.mDone = true;
			if (mEglOwner == thread)
			{
				mEglOwner = null;
			}
			notifyAll();
		}

		/*
		 * Tries once to acquire the right to use an EGL surface. Does not
		 * block.
		 * 
		 * @return true if the right to use an EGL surface was acquired.
		 */
		public synchronized boolean tryAcquireEglSurface(GLThread thread)
		{
			if (mEglOwner == thread || mEglOwner == null)
			{
				mEglOwner = thread;
				notifyAll();
				return true;
			}
			return false;
		}

		public synchronized void releaseEglSurface(GLThread thread)
		{
			if (mEglOwner == thread)
			{
				mEglOwner = null;
			}
			notifyAll();
		}
	}
}

interface EGLConfigChooser
{
	EGLConfig chooseConfig(EGL10 egl, EGLDisplay display);
}

abstract class BaseConfigChooser implements EGLConfigChooser
{
	public BaseConfigChooser(int[] configSpec)
	{
		mConfigSpec = configSpec;
	}

	public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display)
	{
		int[] num_config = new int[1];
		egl.eglChooseConfig(display, mConfigSpec, null, 0, num_config);

		int numConfigs = num_config[0];

		if (numConfigs <= 0)
		{
			throw new IllegalArgumentException("No configs match configSpec");
		}

		EGLConfig[] configs = new EGLConfig[numConfigs];
		egl.eglChooseConfig(display, mConfigSpec, configs, numConfigs, num_config);
		EGLConfig config = chooseConfig(egl, display, configs);
		if (config == null)
		{
			throw new IllegalArgumentException("No config chosen");
		}
		return config;
	}

	abstract EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs);

	protected int[] mConfigSpec;

	public static class ComponentSizeChooser extends BaseConfigChooser
	{
		public ComponentSizeChooser(int redSize, int greenSize, int blueSize, int alphaSize, int depthSize, int stencilSize)
		{
			super(new int[] {EGL10.EGL_RED_SIZE, redSize, EGL10.EGL_GREEN_SIZE, greenSize, EGL10.EGL_BLUE_SIZE, blueSize, EGL10.EGL_ALPHA_SIZE, alphaSize, EGL10.EGL_DEPTH_SIZE, depthSize, EGL10.EGL_STENCIL_SIZE, stencilSize, EGL10.EGL_NONE});
			mValue = new int[1];
			mRedSize = redSize;
			mGreenSize = greenSize;
			mBlueSize = blueSize;
			mAlphaSize = alphaSize;
			mDepthSize = depthSize;
			mStencilSize = stencilSize;
		}

		@Override
		public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs)
		{
			EGLConfig closestConfig = null;
			int closestDistance = 1000;
			for (EGLConfig config : configs)
			{
				int d = findConfigAttrib(egl, display, config, EGL10.EGL_DEPTH_SIZE, 0);
				int s = findConfigAttrib(egl, display, config, EGL10.EGL_STENCIL_SIZE, 0);
				if (d >= mDepthSize && s >= mStencilSize)
				{
					int r = findConfigAttrib(egl, display, config, EGL10.EGL_RED_SIZE, 0);
					int g = findConfigAttrib(egl, display, config, EGL10.EGL_GREEN_SIZE, 0);
					int b = findConfigAttrib(egl, display, config, EGL10.EGL_BLUE_SIZE, 0);
					int a = findConfigAttrib(egl, display, config, EGL10.EGL_ALPHA_SIZE, 0);
					int distance = Math.abs(r - mRedSize) + Math.abs(g - mGreenSize) + Math.abs(b - mBlueSize) + Math.abs(a - mAlphaSize);
					if (distance < closestDistance)
					{
						closestDistance = distance;
						closestConfig = config;
					}
				}
			}
			return closestConfig;
		}

		private int findConfigAttrib(EGL10 egl, EGLDisplay display, EGLConfig config, int attribute, int defaultValue)
		{

			if (egl.eglGetConfigAttrib(display, config, attribute, mValue))
			{
				return mValue[0];
			}
			return defaultValue;
		}

		private int[] mValue;
		// Subclasses can adjust these values:
		protected int mRedSize;
		protected int mGreenSize;
		protected int mBlueSize;
		protected int mAlphaSize;
		protected int mDepthSize;
		protected int mStencilSize;
	}

	/**
	 * This class will choose a supported surface as close to RGB565 as
	 * possible, with or without a depth buffer.
	 * 
	 */
	public static class SimpleEGLConfigChooser extends ComponentSizeChooser
	{
		public SimpleEGLConfigChooser(boolean withDepthBuffer)
		{
			super(4, 4, 4, 0, withDepthBuffer ? 16 : 0, 0);
			// Adjust target values. This way we'll accept a 4444 or
			// 555 buffer if there's no 565 buffer available.
			mRedSize = 5;
			mGreenSize = 6;
			mBlueSize = 5;
		}
	}
}