/*
 *                 Sun Public License Notice
 * 
 * The contents of this file are subject to the Sun Public License
 * Version 1.0 (the "License"). You may not use this file except in
 * compliance with the License. A copy of the License is available at
 * http://www.sun.com/
 * 
 * The Original Code is NetBeans. The Initial Developer of the Original
 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2000 Sun
 * Microsystems, Inc. All Rights Reserved.
 */

package org.openide.explorer.view;

import java.awt.dnd.*;
import java.awt.datatransfer.*;

import javax.swing.JList;
import javax.swing.SwingUtilities;

import org.openide.nodes.Node;
import org.openide.util.datatransfer.PasteType;
import org.openide.util.RequestProcessor;


/**
*
* @author Dafe Simonek
*/
final class ListViewDropSupport 
    implements DropTargetListener, Runnable 
{

    // Attributes

    /** true if support is active, false otherwise */
    boolean active = false;

    boolean dropTargetPopupAllowed;

    /** Drop target asociated with the tree */
    DropTarget dropTarget;

    /** The index of last item the cursor hotspot was above */
    int lastIndex = -1;

    // Associations

    /** View manager. */
    protected ListView view;

    /** The component we are supporting with drop support */
    protected JList list;

    // Operations
    public ListViewDropSupport (ListView view, JList list) {
        this( view, list, true );
    }

    /** Creates new TreeViewDropSupport */
    public ListViewDropSupport (ListView view, JList list, boolean dropTargetPopupAllowed)
    {
        this.view = view;
        this.list = list;
        this.dropTargetPopupAllowed = dropTargetPopupAllowed;
    }

    public void setDropTargetPopupAllowed(boolean value) {
        dropTargetPopupAllowed=value;
    }

    public boolean isDropTargetPopupAllowed() {
        return dropTargetPopupAllowed;
    }

    /** User is starting to drag over us */
    public void dragEnter (DropTargetDragEvent dtde) {
        lastIndex = indexWithCheck(dtde);
        if (lastIndex < 0)
            dtde.rejectDrag();
        else {
            dtde.acceptDrag(dtde.getDropAction());
            NodeRenderer.dragEnter(
                list.getModel().getElementAt(lastIndex));
            list.repaint(list.getCellBounds(lastIndex, lastIndex));
        }
    }

    /** User drags over us */
    public void dragOver (DropTargetDragEvent dtde) {
        int index = indexWithCheck(dtde);
        if (index < 0) {
            dtde.rejectDrag();
            if (lastIndex >= 0) {
                NodeRenderer.dragExit();
                list.repaint(list.getCellBounds(lastIndex, lastIndex));
                lastIndex = -1;
            }
        } else {
            dtde.acceptDrag(dtde.getDropAction());
            if (lastIndex != index) {
                if (lastIndex < 0)
                    lastIndex = index;
                NodeRenderer.dragExit();
                NodeRenderer.dragEnter(list.getModel().getElementAt(index));
                list.repaint(list.getCellBounds(lastIndex, index));
                lastIndex = index;
            }
        }
    }

    public void dropActionChanged (DropTargetDragEvent dtde) {
        // System.out.println("Changing drop action..."); // NOI18N
        // PENDING...?
    }

    /** User exits the dragging */
    public void dragExit (DropTargetEvent dte) {
        if (lastIndex >= 0) {
            NodeRenderer.dragExit();
            list.repaint(list.getCellBounds(lastIndex, lastIndex));
        }
    }

    /** Performs the drop action, if we are dropping on
    * right node and target node agrees.
    */
    public void drop (DropTargetDropEvent dtde) {
        // System.out.println("Dropping!!!"); // NOI18N
        // obtain the node we have cursor on
        int index = list.locationToIndex(dtde.getLocation());
        Object obj = list.getModel().getElementAt(index);
        Node dropNode = null;
        if( obj instanceof VisualizerNode )
            dropNode = ((VisualizerNode) obj).node;
        
        int dropAction = dtde.getDropAction();
        
        // return if conditions are not satisfied
        if (index < 0 || !canDrop (dropNode, dropAction)) {
            dtde.rejectDrop();
            return;
        }
        // get paste types for given transferred transferable
        PasteType[] pt =
            DragDropUtilities.getPasteTypes((Node)obj,
                ExplorerDnDManager.getDefault ().getDraggedTransferable (DnDConstants.ACTION_MOVE==dropAction));
        if ((pt == null) || (pt.length <= 0)) {
            dtde.dropComplete(false);
            // something is wrong, notify user
            // ugly hack, but if we don't wait, deadlock will come
            // (sun's issue....)
            RequestProcessor.getDefault().post(this, 500);
            return;
        }
        // finally perform the drop
        dtde.acceptDrop(dropAction);
        if (dropAction == DnDConstants.ACTION_LINK) {
            // show popup menu to the user
            // PENDING
        } else {
            DragDropUtilities.performPaste (pt[0], null);
        }
    }

    /** Can node recieve given drop action? */
    // XXX canditate for more general support
    private boolean canDrop (Node n, int dropAction) {
        if (n == null) {
            return false;
        }
        
        if (ExplorerDnDManager.getDefault ().getAllowedDragActions()==DnDConstants.ACTION_NONE) {
            return false;
        }
        
        // test if a parent of the dragged nodes isn't the node over
        // only for MOVE action
        if (DnDConstants.ACTION_MOVE==dropAction) {
            Node[] nodes = ExplorerDnDManager.getDefault ().getDraggedNodes();
            for (int i=0; i