/*
 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package com.sun.opengl.impl;

// FIXME: refactor Java SE dependencies
// import java.awt.GraphicsConfiguration;
// import java.awt.GraphicsDevice;
// import java.awt.GraphicsEnvironment;
import java.lang.ref.*;
import java.util.*;
import javax.media.opengl.*;

/** Provides a mechanism by which OpenGL contexts can share textures
    and display lists in the face of multithreading and asynchronous
    context creation as is inherent in the AWT and Swing. */

public class GLContextShareSet {
  // FIXME: refactor Java SE dependencies
  //  private static boolean forceTracking = Debug.isPropertyDefined("jogl.glcontext.forcetracking");
  private static final boolean DEBUG = Debug.debug("GLContextShareSet");

  // This class is implemented with a WeakHashMap that goes from the
  // contexts as keys to a complex data structure as value that tracks
  // context creation and deletion.

  private static Map/*<GLContext, ShareSet>*/ shareMap = new WeakHashMap();
  private static Object dummyValue = new Object();

  private static class ShareSet {
    private Map allShares       = new WeakHashMap();
    private Map createdShares   = new WeakHashMap();
    private Map destroyedShares = new WeakHashMap();

    public void add(GLContext ctx) {
      if (allShares.put(ctx, dummyValue) == null) {
        // FIXME: downcast to GLContextImpl undesirable
        if (((GLContextImpl) ctx).isCreated()) {
          createdShares.put(ctx, dummyValue);
        } else {
          destroyedShares.put(ctx, dummyValue);
        }
      }      
    }

    public GLContext getCreatedShare(GLContext ignore) {
      for (Iterator iter = createdShares.keySet().iterator(); iter.hasNext(); ) {
        GLContext ctx = (GLContext) iter.next();
        if (ctx != ignore) {
          return ctx;
        }
      }
      return null;
    }

    public void contextCreated(GLContext ctx) {
      Object res = destroyedShares.remove(ctx);
      assert res != null : "State of ShareSet corrupted; thought context " +
        ctx + " should have been in destroyed set but wasn't";
      res = createdShares.put(ctx, dummyValue);
      assert res == null : "State of ShareSet corrupted; thought context " +
        ctx + " shouldn't have been in created set but was";
    }

    public void contextDestroyed(GLContext ctx) {
      Object res = createdShares.remove(ctx);
      assert res != null : "State of ShareSet corrupted; thought context " +
        ctx + " should have been in created set but wasn't";
      res = destroyedShares.put(ctx, dummyValue);
      assert res == null : "State of ShareSet corrupted; thought context " +
        ctx + " shouldn't have been in destroyed set but was";
    }
  }

  /** Indicate that contexts <code>share1</code> and
      <code>share2</code> will share textures and display lists. Both
      must be non-null. */
  public static synchronized void registerSharing(GLContext share1, GLContext share2) {
    if (share1 == null || share2 == null) {
      throw new IllegalArgumentException("Both share1 and share2 must be non-null");
    }
    ShareSet share = entryFor(share1);
    if (share == null) {
      share = entryFor(share2);
    }
    if (share == null) {
      share = new ShareSet();
    }
    share.add(share1);
    share.add(share2);
    addEntry(share1, share);
    addEntry(share2, share);
  }

  public static synchronized GLContext getShareContext(GLContext contextToCreate) {
    ShareSet share = entryFor(contextToCreate);
    if (share == null) {
      return null;
    }
    return share.getCreatedShare(contextToCreate);
  }

  public static synchronized void contextCreated(GLContext context) {
    ShareSet share = entryFor(context);
    if (share != null) {
      share.contextCreated(context);
    }
  }

  public static synchronized void contextDestroyed(GLContext context) {
    ShareSet share = entryFor(context);
    if (share != null) {
      share.contextDestroyed(context);
    }
  }

  // FIXME: refactor Java SE dependencies
  //  /** Indicates that the two supplied contexts (which must be able to
  //      share textures and display lists) should be in the same
  //      namespace for tracking of server-side object creation and
  //      deletion. Because the sharing necessary behind the scenes is
  //      different than that requested at the user level, the two notions
  //      are different. This must be called immediately after the
  //      creation of the new context (which is the second argument)
  //      before any server-side OpenGL objects have been created in that
  //      context. */
  //  public static void registerForObjectTracking(GLContext olderContextOrNull,
  //                                               GLContext newContext,
  //                                               GLContext realShareContext) {
  //    if (isObjectTrackingEnabled() || isObjectTrackingDebuggingEnabled()) {
  //      GLContextImpl impl1 = null;      
  //      GLContextImpl impl2 = null;      
  //      GLObjectTracker tracker = null;
  //
  //      synchronized (GLContextShareSet.class) {
  //        if (olderContextOrNull != null &&
  //            newContext != null) {
  //          if (entryFor(olderContextOrNull) != entryFor(newContext)) {
  //            throw new IllegalArgumentException("old and new contexts must be able to share textures and display lists");
  //          }
  //        }
  //
  //        // FIXME: downcast to GLContextImpl undesirable
  //        impl1 = (GLContextImpl) olderContextOrNull;
  //        impl2 = (GLContextImpl) newContext;
  //
  //        GLObjectTracker deletedObjectTracker = null;
  //        GLContextImpl shareImpl = (GLContextImpl) realShareContext;
  //        // Before we zap the "user-level" object trackers, make sure
  //        // that all contexts in the share set share the destroyed object
  //        // tracker
  //        if (shareImpl != null) {
  //          deletedObjectTracker = shareImpl.getDeletedObjectTracker();
  //        }
  //        if (deletedObjectTracker == null) {
  //          // Must create one and possibly set it up in the older context
  //          deletedObjectTracker = new GLObjectTracker();
  //          if (DEBUG) {
  //            System.err.println("Created deletedObjectTracker " + deletedObjectTracker + " because " +
  //                               ((shareImpl == null) ? "shareImpl was null" : "shareImpl's (" + shareImpl + ") deletedObjectTracker was null"));
  //          }
  //
  //          if (shareImpl != null) {
  //            // FIXME: think should really assert in this case
  //            shareImpl.setDeletedObjectTracker(deletedObjectTracker);
  //            if (DEBUG) {
  //              System.err.println("Set deletedObjectTracker " + deletedObjectTracker + " in shareImpl context " + shareImpl);
  //            }
  //          }
  //        }
  //        impl2.setDeletedObjectTracker(deletedObjectTracker);
  //        if (DEBUG) {
  //          System.err.println("Set deletedObjectTracker " + deletedObjectTracker + " in impl2 context " + impl2);
  //        }
  //      }
  //
  //      // Must not hold lock around this operation
  //      // Don't share object trackers with the primordial share context from Java2D
  //      if (Java2D.isOGLPipelineActive()) {
  //        // FIXME: probably need to do something different here
  //        // Need to be able to figure out the GraphicsDevice for the
  //        // older context if it's on-screen
  //        GraphicsConfiguration gc = GraphicsEnvironment.
  //          getLocalGraphicsEnvironment().
  //          getDefaultScreenDevice().
  //          getDefaultConfiguration();
  //        GLContext j2dShareContext = Java2D.getShareContext(gc);
  //        if (impl1 != null && impl1 == j2dShareContext) {
  //          impl1 = null;
  //        }
  //      }
  //
  //      synchronized (GLContextShareSet.class) {
  //        if (impl1 != null) {
  //          tracker = impl1.getObjectTracker();
  //          assert (tracker != null)
  //            : "registerForObjectTracking was not called properly for the older context";
  //        }
  //        if (tracker == null) {
  //          tracker = new GLObjectTracker();
  //        }
  //        // Note that we don't assert that the tracker is non-null for
  //        // impl2 because the way we use this functionality we actually
  //        // overwrite the initially-set object tracker in the new context
  //        impl2.setObjectTracker(tracker);
  //      }
  //    }
  //  }
  //
  //  /** In order to avoid glGet calls for buffer object checks related
  //      to glVertexPointer, etc. calls as well as glMapBuffer calls, we
  //      need to share the same GLBufferSizeTracker object between
  //      contexts sharing textures and display lists. For now we keep
  //      this mechanism orthogonal to the GLObjectTracker to hopefully
  //      keep things easier to understand. (The GLObjectTracker is
  //      currently only needed in a fairly esoteric case, when the
  //      Java2D/JOGL bridge is active, but the GLBufferSizeTracker
  //      mechanism is now always required.) */
  //  public static void registerForBufferObjectSharing(GLContext olderContextOrNull, GLContext newContext) {
  //    // FIXME: downcasts to GLContextImpl undesirable
  //    GLContextImpl older = (GLContextImpl) olderContextOrNull;
  //    GLContextImpl newer = (GLContextImpl) newContext;
  //    GLBufferSizeTracker tracker = null;
  //    if (older != null) {
  //      tracker = older.getBufferSizeTracker();
  //      assert (tracker != null)
  //        : "registerForBufferObjectSharing was not called properly for the older context, or has a bug in it";
  //    }
  //    if (tracker == null) {
  //      tracker = new GLBufferSizeTracker();
  //    }
  //    newer.setBufferSizeTracker(tracker);
  //  }

  //----------------------------------------------------------------------
  // Internals only below this point
  //

  private static ShareSet entryFor(GLContext context) {
    return (ShareSet) shareMap.get(context);
  }

  private static void addEntry(GLContext context, ShareSet share) {
    if (shareMap.get(context) == null) {
      shareMap.put(context, share);
    }
  }

  // FIXME: refactor Java SE dependencies
  //  private static boolean isObjectTrackingEnabled() {
  //    return ((Java2D.isOGLPipelineActive() && Java2D.isFBOEnabled()) ||
  //            isObjectTrackingDebuggingEnabled());
  //  }
  //
  //  private static boolean isObjectTrackingDebuggingEnabled() {
  //    return forceTracking;
  //  }
}