/*
 * @(#)DnDTracker.java
 * 
 * Copyright (c) 2009-2010 The authors and contributors of JHotDraw.
 * 
 * You may not use, copy or modify this file, except in compliance with the 
 * accompanying license terms.
 */
package org.jhotdraw.draw.tool;

import javax.annotation.Nullable;
import org.jhotdraw.draw.*;
import java.awt.Container;
import java.awt.dnd.DnDConstants;
import java.awt.event.MouseEvent;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;

/**
 * This is a tracker which supports drag and drop of figures between drawing
 * views and any other component or application which support drag and drop.
 * <p>
 * DnDTracker can be used stand-alone or instead of {@code DragTracker} in the
 * {@code SelectionTool} or the {@code DelegationSelectionTool}.
 * <p>
 * To get a drag image using drag and drop, the drawing needs to provide
 * an image output format.
 * <p>
 * Drag and Drop is about information moving, not images or objects.  Its about
 * moving a figure to another application and that application understanding
 * both its shape, color, attributes, and everything about it - not necessarily
 * how it looks.
 *
 * @author Werner Randelshofer
 * @version $Id$
 */
public class DnDTracker extends AbstractTool implements DragTracker {
    private static final long serialVersionUID = 1L;

    @Nullable protected Figure anchorFigure;
    /**
     * The drag rectangle encompasses the bounds of all dragged figures.
     */
    @Nullable protected Rectangle2D.Double dragRect;
    /**
     * The previousOrigin holds the origin of all dragged figures of the
     * previous mouseDragged event. This coordinate is constrained using
     * the Constrainer of the DrawingView.
     */
    protected Point2D.Double previousOrigin;
    /**
     * The anchorOrigin holds the origin of all dragged figures of the
     * mousePressed event.
     */
    protected Point2D.Double anchorOrigin;
    /**
     * The previousPoint holds the location of the mouse of the previous
     * mouseDragged event. This coordinate is not constrained using
     * the Constrainer of the DrawingView.
     */
    protected Point2D.Double previousPoint;
    /**
     * The anchorPoint holds the location of the mouse of the
     * mousePressed event. This coordinate is not constrained using
     * the Constrainer of the DrawingView.
     */
    protected Point2D.Double anchorPoint;
    private boolean isDragging;

    public DnDTracker() {
       
    }

    public DnDTracker(Figure figure) {
        anchorFigure = figure;
    }

    @Override
    public void mouseMoved(MouseEvent evt) {
        updateCursor(editor.findView((Container) evt.getSource()), evt.getPoint());
    }
    @Override
    public void mousePressed(MouseEvent evt) {
        super.mousePressed(evt);
        DrawingView view = getView();

        if (evt.isShiftDown()) {
            view.setHandleDetailLevel(0);
            view.toggleSelection(anchorFigure);
            if (!view.isFigureSelected(anchorFigure)) {
                anchorFigure = null;
            }
        } else if (!view.isFigureSelected(anchorFigure)) {
            view.setHandleDetailLevel(0);
            view.clearSelection();
            view.addToSelection(anchorFigure);
        }

        if (!view.getSelectedFigures().isEmpty()) {

            dragRect = null;
            for (Figure f : view.getSelectedFigures()) {
                if (dragRect == null) {
                    dragRect = f.getBounds();
                } else {
                    dragRect.add(f.getBounds());
                }
            }


            anchorPoint = previousPoint = view.viewToDrawing(anchor);
            anchorOrigin = previousOrigin = new Point2D.Double(dragRect.x, dragRect.y);
        }
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        DrawingView v = getView();

        Figure f = v.findFigure(e.getPoint());
        if (f != null) {
            if (!v.getSelectedFigures().contains(f)) {
                v.clearSelection();
                v.addToSelection(f);
            }

            v.getComponent().getTransferHandler().exportAsDrag(v.getComponent(), e, DnDConstants.ACTION_MOVE);
        }
        fireToolDone();
    }

    @Override
    public void mouseReleased(MouseEvent evt) {
            updateCursor(editor.findView((Container) evt.getSource()), evt.getPoint());
        fireToolDone();
    }

    @Override
    public void setDraggedFigure(Figure f) {
        anchorFigure = f;
    }
}