/*

 * Copyright 2003 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.awt.Toolkit;

import java.awt.Component;

import java.awt.Point;

import java.awt.dnd.DnDConstants;

import java.awt.dnd.DragSource;

import java.awt.dnd.MouseDragGestureRecognizer;

import java.awt.dnd.DragGestureListener;

import java.awt.event.InputEvent;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.awt.event.MouseMotionListener;

import java.lang.reflect.*;

import sun.awt.dnd.SunDragSourceContextPeer;

/**

 * <p>

 * This subclass of MouseDragGestureRecognizer defines a DragGestureRecognizer

 * for Mouse based gestures on OSF/Motif.

 * </p>

 *

 * @author Laurence P. G. Cable

 *

 * @see java.awt.dnd.DragGestureListener

 * @see java.awt.dnd.DragGestureEvent

 * @see java.awt.dnd.DragSource

 */

class XMouseDragGestureRecognizer extends MouseDragGestureRecognizer {

    private static final long serialVersionUID = -841711780352520383L;

    /*

     * constant for number of pixels hysterisis before drag is determined

     * to have started

     */

    protected static int motionThreshold;

    protected static final int ButtonMask = InputEvent.BUTTON1_DOWN_MASK |

                                            InputEvent.BUTTON2_DOWN_MASK |

                                            InputEvent.BUTTON3_DOWN_MASK;

    /**

     * construct a new XMouseDragGestureRecognizer

     *

     * @param ds  The DragSource for the Component c

     * @param c   The Component to observe

     * @param act The actions permitted for this Drag

     * @param dgl The DragGestureRecognizer to notify when a gesture is detected

     *

     */

    protected XMouseDragGestureRecognizer(DragSource ds, Component c, int act, DragGestureListener dgl) {

        super(ds, c, act, dgl);

    }

    /**

     * construct a new XMouseDragGestureRecognizer

     *

     * @param ds  The DragSource for the Component c

     * @param c   The Component to observe

     * @param act The actions permitted for this Drag

     */

    protected XMouseDragGestureRecognizer(DragSource ds, Component c, int act) {

        this(ds, c, act, null);

    }

    /**

     * construct a new XMouseDragGestureRecognizer

     *

     * @param ds  The DragSource for the Component c

     * @param c   The Component to observe

     */

    protected XMouseDragGestureRecognizer(DragSource ds, Component c) {

        this(ds, c, DnDConstants.ACTION_NONE);

    }

    /**

     * construct a new XMouseDragGestureRecognizer

     *

     * @param ds  The DragSource for the Component c

     */

    protected XMouseDragGestureRecognizer(DragSource ds) {

        this(ds, null);

    }

    /**

     * determine the drop action from the event

     */

    protected int mapDragOperationFromModifiers(MouseEvent e) {

        int mods = e.getModifiersEx();

        int btns = mods & ButtonMask;

        // Do not allow right mouse button drag since Motif DnD does not

        // terminate drag operation on right mouse button release.

        if (!(btns == InputEvent.BUTTON1_DOWN_MASK ||

              btns == InputEvent.BUTTON2_DOWN_MASK)) {

            return DnDConstants.ACTION_NONE;

        }

        return

            SunDragSourceContextPeer.convertModifiersToDropAction(mods,

                                                                  getSourceActions());

    }

    /**

     * Invoked when the mouse has been clicked on a component.

     */

    public void mouseClicked(MouseEvent e) {

        // do nothing

    }

    /**

     * Invoked when a mouse button has been pressed on a component.

     */

    public void mousePressed(MouseEvent e) {

        events.clear();

        if (mapDragOperationFromModifiers(e) != DnDConstants.ACTION_NONE) {

            try {

                motionThreshold = DragSource.getDragThreshold();

            } catch (Exception exc) {

                motionThreshold = 5;

            }

            appendEvent(e);

        }

    }

    /**

     * Invoked when a mouse button has been released on a component.

     */

    public void mouseReleased(MouseEvent e) {

        events.clear();

    }

    /**

     * Invoked when the mouse enters a component.

     */

    public void mouseEntered(MouseEvent e) {

        events.clear();

    }

    /**

     * Invoked when the mouse exits a component.

     */

    public void mouseExited(MouseEvent e) {

        if (!events.isEmpty()) { // gesture pending

            int dragAction = mapDragOperationFromModifiers(e);

            if (dragAction == DnDConstants.ACTION_NONE) {

                events.clear();

            }

        }

    }

    /**

     * Invoked when a mouse button is pressed on a component.

     */

    public void mouseDragged(MouseEvent e) {

        if (!events.isEmpty()) { // gesture pending

            int dop = mapDragOperationFromModifiers(e);

            if (dop == DnDConstants.ACTION_NONE) {

                return;

            }

            MouseEvent trigger = (MouseEvent)events.get(0);

            Point      origin  = trigger.getPoint();

            Point      current = e.getPoint();

            int        dx      = Math.abs(origin.x - current.x);

            int        dy      = Math.abs(origin.y - current.y);

            if (dx > motionThreshold || dy > motionThreshold) {

                fireDragGestureRecognized(dop, ((MouseEvent)getTriggerEvent()).getPoint());

            } else

                appendEvent(e);

        }

    }

    /**

     * Invoked when the mouse button has been moved on a component

     * (with no buttons no down).

     */

    public void mouseMoved(MouseEvent e) {

        // do nothing

    }

}