/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package javax.microedition.m3g;

import java.lang.ref.WeakReference;

import java.util.Hashtable;

import org.eclipse.swt.widgets.Display;

#ifdef RD_JAVA_OMJ

import com.nokia.mj.impl.rt.support.Finalizer;

#endif // RD_JAVA_OMJ

/**

 * M3G interface object. An interface is automatically created for

 * each MIDlet using the 3D API to keep track of Java-side object

 * lifetimes etc.

 */

class Interface

{

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

    // Static data

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

    // Common class enumeration for Java and native code

    private static final int ANIMATION_CONTROLLER = 0x01;

    private static final int ANIMATION_TRACK      = 0x02;

    private static final int APPEARANCE           = 0x03;

    private static final int BACKGROUND           = 0x04;

    private static final int CAMERA               = 0x05;

    private static final int COMPOSITING_MODE     = 0x06;

    private static final int FOG                  = 0x07;

    private static final int GROUP                = 0x08;

    private static final int IMAGE_2D             = 0x09;

    private static final int INDEX_BUFFER         = 0x0A;

    private static final int KEYFRAME_SEQUENCE    = 0x0B;

    private static final int LIGHT                = 0x0C;

    private static final int LOADER               = 0x0D;

    private static final int MATERIAL             = 0x0E;

    private static final int MESH                 = 0x0F;

    private static final int MORPHING_MESH        = 0x10;

    private static final int POLYGON_MODE         = 0x11;

    private static final int RENDER_CONTEXT       = 0x12;

    private static final int SKINNED_MESH         = 0x13;

    private static final int SPRITE_3D            = 0x14;

    private static final int TEXTURE_2D           = 0x15;

    private static final int VERTEX_ARRAY         = 0x16;

    private static final int VERTEX_BUFFER        = 0x17;

    private static final int WORLD                = 0x18;

    // Once created, the interface singleton currently remains in

    // memory until VM exit.  By using a WeakReference here, with hard

    // references stored in each object, it could be GC'd when no more

    // objects exist, but that probably isn't worth the extra memory

    // overhead.

    //private static Hashtable s_instances = new Hashtable();

    private static Interface instance = null;

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

    // Instance data

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

    /**

     * Handle of the native interface object.

     */

    private int handle;

    /**

     * Global handle-to-Object3D map used to both find the Java

     * counterparts of objects returned from the native methods, and

     * keep certain objects from being garbage collected.

     */

    private final Hashtable liveObjects = new Hashtable();

    /**

     * Flag for shutdown signal

     */

    private boolean iShutdown = false;

    /**

     * Flag for native peer init state

     */

    private boolean iNativeInitialized = false;

#ifdef RD_JAVA_OMJ

    private Finalizer mFinalizer;

#endif // RD_JAVA_OMJ

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

    // Constructors

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

    private Interface()

    {

        // Contruct native peer

        initNativePeer();

#ifdef RD_JAVA_OMJ

        mFinalizer = new Finalizer()

        {

            public void finalizeImpl()

            {

                doFinalize();

            }

        };

#else // RD_JAVA_OMJ

        Platform.registerFinalizer(this);

#endif // RD_JAVA_OMJ

    }

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

    // Package methods

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

    /**

     * Returns the M3G interface instance for the current MIDlet.

     */

    static final Interface getInstance()

    {

        if (instance == null)

        {

            instance = new Interface();

        }

        return instance;

    }

    /**

     * Returns the native handle of the current Interface instance.

     */

    static final int getHandle()

    {

        getInstance().integrityCheck();

        return getInstance().handle;

    }

    /**

     * Registers an Object3D with this interface. The object is added

     * to the global handle-to-object map, and the native finalization

     * callback is set up. The handle of the object must already be

     * set at this point!

     */

    static final void register(Object3D obj)

    {

        Platform.registerFinalizer(obj);

        getInstance().liveObjects.put(new Integer(obj.handle),

                                      new WeakReference(obj));

    }

    static final void register(Loader obj)

    {

        Platform.registerFinalizer(obj);

        getInstance().liveObjects.put(new Integer(obj.handle),

                                      new WeakReference(obj));

    }

    /**

     * Finds an Object3D in the global handle-to-object map. Also

     * removes dead objects (that is, null references) from the map

     * upon encountering them.

     */

    static final Object3D findObject(int handle)

    {

        Interface self = getInstance();

        Integer iHandle = new Integer(handle);

        Object ref = self.liveObjects.get(iHandle);

        if (ref != null)

        {

            Object3D obj = (Object3D)((WeakReference)ref).get();

            if (obj == null)

            {

                self.liveObjects.remove(iHandle);

            }

            return obj;

        }

        else

        {

            return null;

        }

    }

    /**

     * Returns the Java object representing a native object, or

     * creates a new proxy/peer if one doesn't exist yet.

     */

    static final Object3D getObjectInstance(int handle)

    {

        // A zero handle equals null

        if (handle == 0)

        {

            return null;

        }

        // Then try to find an existing Java representative for the

        // object

        Object3D obj = findObject(handle);

        if (obj != null)

        {

            return obj;

        }

        // Not found, create a new Java object. Note that only

        // non-abstract classes can possibly be returned.

        switch (_getClassID(handle))

        {

        case ANIMATION_CONTROLLER:

            return new AnimationController(handle);

        case ANIMATION_TRACK:

            return new AnimationTrack(handle);

        case APPEARANCE:

            return new Appearance(handle);

        case BACKGROUND:

            return new Background(handle);

        case CAMERA:

            return new Camera(handle);

        case COMPOSITING_MODE:

            return new CompositingMode(handle);

        case FOG:

            return new Fog(handle);

        case GROUP:

            return new Group(handle);

        case IMAGE_2D:

            return new Image2D(handle);

        case INDEX_BUFFER:

            return new TriangleStripArray(handle);

        case KEYFRAME_SEQUENCE:

            return new KeyframeSequence(handle);

        case LIGHT:

            return new Light(handle);

            //case LOADER:

        case MATERIAL:

            return new Material(handle);

        case MESH:

            return new Mesh(handle);

        case MORPHING_MESH:

            return new MorphingMesh(handle);

        case POLYGON_MODE:

            return new PolygonMode(handle);

            //case RENDER_CONTEXT:

        case SKINNED_MESH:

            return new SkinnedMesh(handle);

        case SPRITE_3D:

            return new Sprite3D(handle);

        case TEXTURE_2D:

            return new Texture2D(handle);

        case VERTEX_ARRAY:

            return new VertexArray(handle);

        case VERTEX_BUFFER:

            return new VertexBuffer(handle);

        case WORLD:

            return new World(handle);

        default:

            throw new Error();

        }

    }

    /**

     * Forces removal of an object from the handle-to-object map.

     */

    static final void deregister(Object3D obj, Interface self)

    {

        self.liveObjects.remove(new Integer(obj.handle));

        if (self.liveObjects.isEmpty() && self.iShutdown)

        {

            self.registeredFinalize();

        }

    }

    /**

     * Forces removal of an object from the handle-to-object map.

     */

    static final void deregister(Loader obj, Interface self)

    {

        self.liveObjects.remove(new Integer(obj.handle));

        if (self.liveObjects.isEmpty() && self.iShutdown)

        {

            self.registeredFinalize();

        }

    }

    /**

     *  Sets shutdown indication flag. Actual native

     *  cleanup occurs when liveObjects count is zero

     */

    void signalShutdown()

    {

        iShutdown = true;

    }

    /**

     * Gets the state of this interface

     * @return true if interface is fully constructed, otherwise false

     */

    boolean isFullyInitialized()

    {

        return iNativeInitialized;

    }

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

    // Private methods

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

    /**

     * Checks the status of the native interface

     */

    private void integrityCheck()

    {

        if (!iNativeInitialized)

        {

            // If native interface cannot be initialized we cannot recover from it

            if (!initNativePeer())

            {

                throw new Error("UI thread not available");

            }

        }

    }

    /**

     * Initializes native peer

     * @return true if native interface was succesfully inialized otherwise false

     */

    private boolean initNativePeer()

    {

        if (iNativeInitialized)

        {

            return true;

        }

        if (Platform.uiThreadAvailable())

        {

            Platform.executeInUIThread(

                new M3gRunnable()

            {

                public void doRun()

                {

                    handle = _ctor();

                }

            });

            iNativeInitialized = true;

            return true;

        }

        else

        {

            return false;

        }

    }

#ifdef RD_JAVA_OMJ

    private void doFinalize()

    {

        if (mFinalizer != null)

        {

            registeredFinalize();

            mFinalizer = null;

        }

    }

#endif // RD_JAVA_OMJ

    // Native finalization hook, for Symbian only

    final private void registeredFinalize()

    {

        if (Interface.instance != null)

        {

            // Finalize M3G interface

            Platform.executeInUIThread(

                new M3gRunnable()

            {

                public void doRun()

                {

                    Platform.finalizeInterface(handle);

                }

            });

            Interface.instance = null;

        }

    }

    // Native constructor

    private static native int _ctor();

    // Native class ID resolver

    private static native int _getClassID(int hObject);

}