/*

 * Copyright 2003-2008 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.awt.X11;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.logging.*;

import java.awt.Point;

/**

 * The class responsible for registration/deregistration of drop sites.

 *

 * @since 1.5

 */

final class XDropTargetRegistry {

    private static final Logger logger =

        Logger.getLogger("sun.awt.X11.xembed.xdnd.XDropTargetRegistry");

    private static final long DELAYED_REGISTRATION_PERIOD = 200;

    private static final XDropTargetRegistry theInstance =

        new XDropTargetRegistry();

    private final HashMap<Long, Runnable> delayedRegistrationMap =

        new HashMap<Long, Runnable>();

    private XDropTargetRegistry() {}

    static XDropTargetRegistry getRegistry() {

        return theInstance;

    }

    /**

     * Returns the XID of the topmost window with WM_STATE set in the ancestor

     * heirarchy of the specified window or 0 if none found.

     */

    private long getToplevelWindow(long window) {

        XBaseWindow candWindow = XToolkit.windowToXWindow(window);

        if (candWindow != null) {

            XWindowPeer toplevel = candWindow.getToplevelXWindow();

            if (toplevel != null && !(toplevel instanceof XEmbeddedFramePeer)) {

                return toplevel.getWindow();

            }

        }

        /* Traverse the ancestor tree from window up to the root and find

           the top-level client window nearest to the root. */

        do {

            if (XlibUtil.isTrueToplevelWindow(window)) {

                return window;

            }

            window = XlibUtil.getParentWindow(window);

        } while (window != 0);

        return window;

    }

    static final long getDnDProxyWindow() {

        return XWindow.getXAWTRootWindow().getWindow();

    }

    private static final class EmbeddedDropSiteEntry {

        private final long root;

        private final long event_mask;

        private List<XDropTargetProtocol> supportedProtocols;

        private final HashSet<Long> nonXEmbedClientSites = new HashSet<Long>();

        private final List<Long> sites = new ArrayList<Long>();

        public EmbeddedDropSiteEntry(long root, long event_mask,

                                     List<XDropTargetProtocol> supportedProtocols) {

            if (supportedProtocols == null) {

                throw new NullPointerException("Null supportedProtocols");

            }

            this.root = root;

            this.event_mask = event_mask;

            this.supportedProtocols = supportedProtocols;

        }

        public long getRoot() {

            return root;

        }

        public long getEventMask() {

            return event_mask;

        }

        public boolean hasNonXEmbedClientSites() {

            return !nonXEmbedClientSites.isEmpty();

        }

        public synchronized void addSite(long window, boolean isXEmbedClient) {

            Long lWindow = Long.valueOf(window);

            if (!sites.contains(lWindow)) {

                sites.add(lWindow);

            }

            if (!isXEmbedClient) {

                nonXEmbedClientSites.add(lWindow);

            }

        }

        public synchronized void removeSite(long window) {

            Long lWindow = Long.valueOf(window);

            sites.remove(lWindow);

            nonXEmbedClientSites.remove(lWindow);

        }

        public void setSupportedProtocols(List<XDropTargetProtocol> list) {

            supportedProtocols = list;

        }

        public List<XDropTargetProtocol> getSupportedProtocols() {

            return supportedProtocols;

        }

        public boolean hasSites() {

            return !sites.isEmpty();

        }

        public long[] getSites() {

            long[] ret = new long[sites.size()];

            Iterator iter = sites.iterator();

            int index = 0;

            while (iter.hasNext()) {

                Long l = (Long)iter.next();

                ret[index++] = l.longValue();

            }

            return ret;

        }

        public long getSite(int x, int y) {

            assert XToolkit.isAWTLockHeldByCurrentThread();

            Iterator<Long> iter = sites.iterator();

            while (iter.hasNext()) {

                Long l = iter.next();

                long window = l.longValue();

                Point p = XBaseWindow.toOtherWindow(getRoot(), window, x, y);

                if (p == null) {

                    continue;

                }

                int dest_x = p.x;

                int dest_y = p.y;

                if (dest_x >= 0 && dest_y >= 0) {

                    XWindowAttributes wattr = new XWindowAttributes();

                    try {

                        int status = XlibWrapper.XGetWindowAttributes(XToolkit.getDisplay(),

                                                                      window, wattr.pData);

                        XToolkit.RESTORE_XERROR_HANDLER();

                        if (status == 0 ||

                            (XToolkit.saved_error != null &&

                             XToolkit.saved_error.get_error_code() != XConstants.Success)) {

                            continue;

                        }

                        if (wattr.get_map_state() != XConstants.IsUnmapped

                            && dest_x < wattr.get_width()

                            && dest_y < wattr.get_height()) {

                            return window;

                        }

                    } finally {

                        wattr.dispose();

                    }

                }

            }

            return 0;

        }

    }

    private final HashMap<Long, EmbeddedDropSiteEntry> embeddedDropSiteRegistry =

        new HashMap<Long, EmbeddedDropSiteEntry>();

    private EmbeddedDropSiteEntry registerEmbedderDropSite(long embedder) {

        assert XToolkit.isAWTLockHeldByCurrentThread();

        Iterator dropTargetProtocols =

            XDragAndDropProtocols.getDropTargetProtocols();

        // The list of protocols supported by the embedder.

        List<XDropTargetProtocol> embedderProtocols = new ArrayList();

        while (dropTargetProtocols.hasNext()) {

            XDropTargetProtocol dropTargetProtocol =

                (XDropTargetProtocol)dropTargetProtocols.next();

            if (dropTargetProtocol.isProtocolSupported(embedder)) {

                embedderProtocols.add(dropTargetProtocol);

            }

        }

        embedderProtocols = Collections.unmodifiableList(embedderProtocols);

        /* Grab server, since we are working with the window that belongs to

           another client. */

        XlibWrapper.XGrabServer(XToolkit.getDisplay());

        try {

            long root = 0;

            long event_mask = 0;

            XWindowAttributes wattr = new XWindowAttributes();

            try {

                int status = XlibWrapper.XGetWindowAttributes(XToolkit.getDisplay(),

                                                              embedder, wattr.pData);

                XToolkit.RESTORE_XERROR_HANDLER();

                if (status == 0 ||

                    (XToolkit.saved_error != null &&

                     XToolkit.saved_error.get_error_code() != XConstants.Success)) {

                    throw new XException("XGetWindowAttributes failed");

                }

                event_mask = wattr.get_your_event_mask();

                root = wattr.get_root();

            } finally {

                wattr.dispose();

            }

            if ((event_mask & XConstants.PropertyChangeMask) == 0) {

                XlibWrapper.XSelectInput(XToolkit.getDisplay(), embedder,

                                         event_mask | XConstants.PropertyChangeMask);

                XToolkit.RESTORE_XERROR_HANDLER();

                if (XToolkit.saved_error != null &&

                    XToolkit.saved_error.get_error_code() != XConstants.Success) {

                    throw new XException("XSelectInput failed");

                }

            }

            return new EmbeddedDropSiteEntry(root, event_mask, embedderProtocols);

        } finally {

            XlibWrapper.XUngrabServer(XToolkit.getDisplay());

        }

    }

    private static final boolean XEMBED_PROTOCOLS = true;

    private static final boolean NON_XEMBED_PROTOCOLS = false;

    private void registerProtocols(long embedder, boolean protocols,

                                   List<XDropTargetProtocol> supportedProtocols) {

        Iterator dropTargetProtocols = null;

        /*

         * By default, we register a drop site that supports all dnd

         * protocols. This approach is not appropriate in plugin

         * scenario if the browser supports Motif DnD and doesn't support

         * XDnD. If we forcibly set XdndAware on the browser toplevel, any drag

         * source that supports both protocols and prefers XDnD will be unable

         * to drop anything on the browser.

         * The solution for this problem is not to register XDnD drop site

         * if the browser supports only Motif DnD.

         * In general, if the browser already supports some protocols, we

         * register the embedded drop site only for those protocols. Otherwise

         * we register the embedded drop site for all protocols.

         */

        if (!supportedProtocols.isEmpty()) {

            dropTargetProtocols = supportedProtocols.iterator();

        } else {

            dropTargetProtocols =

                XDragAndDropProtocols.getDropTargetProtocols();

        }

        /* Grab server, since we are working with the window that belongs to

           another client. */

        XlibWrapper.XGrabServer(XToolkit.getDisplay());

        try {

            while (dropTargetProtocols.hasNext()) {

                XDropTargetProtocol dropTargetProtocol =

                    (XDropTargetProtocol)dropTargetProtocols.next();

                if ((protocols == XEMBED_PROTOCOLS) ==

                    dropTargetProtocol.isXEmbedSupported()) {

                    dropTargetProtocol.registerEmbedderDropSite(embedder);

                }

            }

        } finally {

            XlibWrapper.XUngrabServer(XToolkit.getDisplay());

        }

    }

    public void updateEmbedderDropSite(long embedder) {

        XBaseWindow xbaseWindow = XToolkit.windowToXWindow(embedder);

        // No need to update our own drop sites.

        if (xbaseWindow != null) {

            return;

        }

        assert XToolkit.isAWTLockHeldByCurrentThread();

        Iterator dropTargetProtocols =

            XDragAndDropProtocols.getDropTargetProtocols();

        // The list of protocols supported by the embedder.

        List<XDropTargetProtocol> embedderProtocols = new ArrayList();

        while (dropTargetProtocols.hasNext()) {

            XDropTargetProtocol dropTargetProtocol =

                (XDropTargetProtocol)dropTargetProtocols.next();

            if (dropTargetProtocol.isProtocolSupported(embedder)) {

                embedderProtocols.add(dropTargetProtocol);

            }

        }

        embedderProtocols = Collections.unmodifiableList(embedderProtocols);

        Long lToplevel = Long.valueOf(embedder);

        boolean isXEmbedServer = false;

        synchronized (this) {

            EmbeddedDropSiteEntry entry =

                (EmbeddedDropSiteEntry)embeddedDropSiteRegistry.get(lToplevel);

            if (entry == null) {

                return;

            }

            entry.setSupportedProtocols(embedderProtocols);

            isXEmbedServer = !entry.hasNonXEmbedClientSites();

        }

        /*

         * By default, we register a drop site that supports all dnd

         * protocols. This approach is not appropriate in plugin

         * scenario if the browser supports Motif DnD and doesn't support

         * XDnD. If we forcibly set XdndAware on the browser toplevel, any drag

         * source that supports both protocols and prefers XDnD will be unable

         * to drop anything on the browser.

         * The solution for this problem is not to register XDnD drop site

         * if the browser supports only Motif DnD.

         * In general, if the browser already supports some protocols, we

         * register the embedded drop site only for those protocols. Otherwise

         * we register the embedded drop site for all protocols.

         */

        if (!embedderProtocols.isEmpty()) {

            dropTargetProtocols = embedderProtocols.iterator();

        } else {

            dropTargetProtocols =

                XDragAndDropProtocols.getDropTargetProtocols();

        }

        /* Grab server, since we are working with the window that belongs to

           another client. */

        XlibWrapper.XGrabServer(XToolkit.getDisplay());

        try {

            while (dropTargetProtocols.hasNext()) {

                XDropTargetProtocol dropTargetProtocol =

                    (XDropTargetProtocol)dropTargetProtocols.next();

                if (!isXEmbedServer || !dropTargetProtocol.isXEmbedSupported()) {

                    dropTargetProtocol.registerEmbedderDropSite(embedder);

                }

            }

        } finally {

            XlibWrapper.XUngrabServer(XToolkit.getDisplay());

        }

    }

    private void unregisterEmbedderDropSite(long embedder,

                                            EmbeddedDropSiteEntry entry) {

        assert XToolkit.isAWTLockHeldByCurrentThread();

        Iterator dropTargetProtocols =

            XDragAndDropProtocols.getDropTargetProtocols();

        /* Grab server, since we are working with the window that belongs to

           another client. */

        XlibWrapper.XGrabServer(XToolkit.getDisplay());

        try {

            while (dropTargetProtocols.hasNext()) {

                XDropTargetProtocol dropTargetProtocol =

                    (XDropTargetProtocol)dropTargetProtocols.next();

                dropTargetProtocol.unregisterEmbedderDropSite(embedder);

            }

            long event_mask = entry.getEventMask();

            /* Restore the original event mask for the embedder. */

            if ((event_mask & XConstants.PropertyChangeMask) == 0) {

                XlibWrapper.XSelectInput(XToolkit.getDisplay(), embedder,

                                         event_mask);

                XToolkit.RESTORE_XERROR_HANDLER();

                if (XToolkit.saved_error != null &&

                    XToolkit.saved_error.get_error_code() != XConstants.Success) {

                    throw new XException("XSelectInput failed");

                }

            }

        } finally {

            XlibWrapper.XUngrabServer(XToolkit.getDisplay());

        }

    }

    private void registerEmbeddedDropSite(long toplevel, long window) {

        XBaseWindow xBaseWindow = XToolkit.windowToXWindow(window);

        boolean isXEmbedClient =

            (xBaseWindow instanceof XEmbeddedFramePeer) &&

            ((XEmbeddedFramePeer)xBaseWindow).isXEmbedActive();

        XEmbedCanvasPeer peer = null;

        {

            XBaseWindow xbaseWindow = XToolkit.windowToXWindow(toplevel);

            if (xbaseWindow != null) {

                if (xbaseWindow instanceof XEmbedCanvasPeer) {

                    peer = (XEmbedCanvasPeer)xbaseWindow;

                } else {

                    throw new UnsupportedOperationException();

                }

            }

        }

        Long lToplevel = Long.valueOf(toplevel);

        EmbeddedDropSiteEntry entry = null;

        synchronized (this) {

            entry =

                (EmbeddedDropSiteEntry)embeddedDropSiteRegistry.get(lToplevel);

            if (entry == null) {

                if (peer != null) {

                    // Toplevel is an XEmbed server within this VM.

                    // Register an XEmbed drop site.

                    peer.setXEmbedDropTarget();

                    // Create a dummy entry to register the embedded site.

                    entry = new EmbeddedDropSiteEntry(0, 0,

                                                      Collections.<XDropTargetProtocol>emptyList());

                } else {

                    // Foreign toplevel.

                    // Select for PropertyNotify events on the toplevel, so that

                    // we can track changes of the properties relevant to DnD

                    // protocols.

                    entry = registerEmbedderDropSite(toplevel);

                    // Register the toplevel with all DnD protocols that are not

                    // supported by XEmbed - actually setup a proxy, so that

                    // all DnD notifications sent to the toplevel are first

                    // routed to us.

                    registerProtocols(toplevel, NON_XEMBED_PROTOCOLS,

                                      entry.getSupportedProtocols());

                }

                embeddedDropSiteRegistry.put(lToplevel, entry);

            }

        }

        assert entry != null;

        synchronized (entry) {

            // For a foreign toplevel.

            if (peer == null) {

                if (!isXEmbedClient) {

                    // Since this is not an XEmbed client we can no longer rely

                    // on XEmbed to route DnD notifications even for DnD

                    // protocols that are supported by XEmbed.

                    // We rollback to the XEmbed-unfriendly solution - setup

                    // a proxy, so that all DnD notifications sent to the

                    // toplevel are first routed to us.

                    registerProtocols(toplevel, XEMBED_PROTOCOLS,

                                      entry.getSupportedProtocols());

                } else {

                    Iterator dropTargetProtocols =

                        XDragAndDropProtocols.getDropTargetProtocols();

                    // Register the embedded window as a plain drop site with

                    // all DnD protocols that are supported by XEmbed.

                    while (dropTargetProtocols.hasNext()) {

                        XDropTargetProtocol dropTargetProtocol =

                            (XDropTargetProtocol)dropTargetProtocols.next();

                        if (dropTargetProtocol.isXEmbedSupported()) {

                            dropTargetProtocol.registerEmbedderDropSite(window);

                        }

                    }

                }

            }

            entry.addSite(window, isXEmbedClient);

        }

    }

    private void unregisterEmbeddedDropSite(long toplevel, long window) {

        Long lToplevel = Long.valueOf(toplevel);

        EmbeddedDropSiteEntry entry = null;

        synchronized (this) {

            entry =

                (EmbeddedDropSiteEntry)embeddedDropSiteRegistry.get(lToplevel);

            if (entry == null) {

                return;

            }

            entry.removeSite(window);

            if (!entry.hasSites()) {

                embeddedDropSiteRegistry.remove(lToplevel);

                XBaseWindow xbaseWindow = XToolkit.windowToXWindow(toplevel);

                if (xbaseWindow != null) {

                    if (xbaseWindow instanceof XEmbedCanvasPeer) {

                        XEmbedCanvasPeer peer = (XEmbedCanvasPeer)xbaseWindow;

                        // Unregister an XEmbed drop site.

                        peer.removeXEmbedDropTarget();

                    } else {

                        throw new UnsupportedOperationException();

                    }

                } else {

                    unregisterEmbedderDropSite(toplevel, entry);

                }

            }

        }

    }

    /*

     * Returns a drop site that is embedded in the specified embedder window and

     * contains the point with the specified root coordinates.

     */