/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.gvt.text;

import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.Iterator;

import org.apache.batik.gvt.GraphicsNode;
import org.apache.batik.gvt.RootGraphicsNode;
import org.apache.batik.gvt.Selectable;
import org.apache.batik.gvt.Selector;
import org.apache.batik.gvt.TextNode;
import org.apache.batik.gvt.event.GraphicsNodeChangeEvent;
import org.apache.batik.gvt.event.GraphicsNodeEvent;
import org.apache.batik.gvt.event.GraphicsNodeKeyEvent;
import org.apache.batik.gvt.event.GraphicsNodeMouseEvent;
import org.apache.batik.gvt.event.SelectionEvent;
import org.apache.batik.gvt.event.SelectionListener;

/**
 * A simple implementation of GraphicsNodeMouseListener for text selection.
 *
 * @author <a href="mailto:bill.haneman@ireland.sun.com">Bill Haneman</a>
 * @version $Id$
 */

public class ConcreteTextSelector implements Selector {

    private ArrayList listeners;
    private GraphicsNode selectionNode;
    private RootGraphicsNode selectionNodeRoot;

    public ConcreteTextSelector() {
    }

    public void mouseClicked(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void mouseDragged(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void mouseEntered(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void mouseExited(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void mouseMoved(GraphicsNodeMouseEvent evt) {
    }

    public void mousePressed(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void mouseReleased(GraphicsNodeMouseEvent evt) {
        checkSelectGesture(evt);
    }

    public void keyPressed(GraphicsNodeKeyEvent evt) {
        report(evt, "keyPressed");
    }

    public void keyReleased(GraphicsNodeKeyEvent evt) {
        report(evt, "keyReleased");
    }

    public void keyTyped(GraphicsNodeKeyEvent evt) {
        report(evt, "keyTyped");
    }

    public void changeStarted (GraphicsNodeChangeEvent gnce) {
    }

    public void changeCompleted (GraphicsNodeChangeEvent gnce) {
        if (selectionNode == null) {
            return;
        }
        Shape newShape =
            ((Selectable)selectionNode).getHighlightShape();
        dispatchSelectionEvent
            (new SelectionEvent(getSelection(),
                                SelectionEvent.SELECTION_CHANGED,
                                newShape));
    }

    public void setSelection(Mark begin, Mark end) {
        TextNode node = begin.getTextNode();
        if (node != end.getTextNode()) {
            throw new Error("Markers not from same TextNode");
        }
        node.setSelection(begin, end);
        selectionNode = node;
        selectionNodeRoot = node.getRoot();
        Object selection = getSelection();
        Shape  shape     = node.getHighlightShape();
        dispatchSelectionEvent(new SelectionEvent
            (selection, SelectionEvent.SELECTION_DONE, shape));
    }

    public void clearSelection() {
        if (selectionNode == null) {
            return;
        }
        dispatchSelectionEvent(new SelectionEvent
            (null, SelectionEvent.SELECTION_CLEARED, null));
        selectionNode = null;
        selectionNodeRoot = null;
    }

    /*
     * Checks the event to see if it is a selection gesture and processes it
     * accordingly.
     * @param evt the GraphicsNodeEvent, which may be a "select gesture"
     * Param evt is a GraphicsNodeEvent rather than a GraphicsNodeMouseEvent
     * for future extension, so we can use Shift-arrow, etc.
     */
    protected void checkSelectGesture(GraphicsNodeEvent evt) {

        GraphicsNodeMouseEvent mevt = null;
        if (evt instanceof GraphicsNodeMouseEvent) {
            mevt = (GraphicsNodeMouseEvent) evt;
        }

        GraphicsNode source = evt.getGraphicsNode();
        if (isDeselectGesture(evt)) {
            if (selectionNode != null) {
                selectionNodeRoot.removeTreeGraphicsNodeChangeListener(this);
            }
            clearSelection();
        } else if (mevt != null) {

            Point2D p = new Point2D.Double(mevt.getX(), mevt.getY());
            AffineTransform t = source.getGlobalTransform();
            if (t == null) {
                t = new AffineTransform();
            }
            else {
                 try {
                     t = t.createInverse();
                 } catch (NoninvertibleTransformException ni) {
                 }
            }
            p = t.transform(p, null);

            if ((source instanceof Selectable) && 
                (isSelectStartGesture(evt))) {
                if (selectionNode != source) {
                    if (selectionNode != null) {
                        selectionNodeRoot
                            .removeTreeGraphicsNodeChangeListener(this);
                    }
                    selectionNode = source;
                    if (source != null) {
                        selectionNodeRoot = source.getRoot();
                        selectionNodeRoot
                            .addTreeGraphicsNodeChangeListener(this);
                    }
                }

                ((Selectable) source).selectAt(p.getX(), p.getY());
                dispatchSelectionEvent(
                        new SelectionEvent(null,
                                SelectionEvent.SELECTION_STARTED,
                                null));

            } else if (isSelectEndGesture(evt)) {
                if (selectionNode == source)  {
                    ((Selectable) source).selectTo(p.getX(), p.getY());
                }
                Object oldSelection = getSelection();
                if (selectionNode != null) {
                    Shape newShape;
                    newShape = ((Selectable)selectionNode).getHighlightShape();
                    dispatchSelectionEvent
                        (new SelectionEvent(oldSelection,
                                            SelectionEvent.SELECTION_DONE,
                                            newShape));
                }
            } else if (isSelectContinueGesture(evt)) {

                if (selectionNode == source) {
                    boolean result = ((Selectable) source).selectTo(p.getX(), 
                                                                    p.getY());
                    if (result) {
                        Shape newShape =
                            ((Selectable) selectionNode).getHighlightShape();

                        dispatchSelectionEvent(
                            new SelectionEvent(null,
                                SelectionEvent.SELECTION_CHANGED,
                                newShape));
                    }
                }
            } else if ((source instanceof Selectable) && 
                       (isSelectAllGesture(evt))) {
                if (selectionNode != source) {
                    if (selectionNode != null) {
                        selectionNodeRoot
                            .removeTreeGraphicsNodeChangeListener(this);
                    }
                    selectionNode = source;
                    if (source != null) {
                        selectionNodeRoot = source.getRoot();
                        selectionNodeRoot
                            .addTreeGraphicsNodeChangeListener(this);
                    }
                }
                ((Selectable) source).selectAll(p.getX(), p.getY());
                Object oldSelection = getSelection();
                Shape newShape =
                    ((Selectable) source).getHighlightShape();
                dispatchSelectionEvent(
                        new SelectionEvent(oldSelection,
                                SelectionEvent.SELECTION_DONE,
                                newShape));
            }
        }
    }

    private boolean isDeselectGesture(GraphicsNodeEvent evt) {
        return ((evt.getID() == GraphicsNodeMouseEvent.MOUSE_CLICKED)
            && (((GraphicsNodeMouseEvent) evt).getClickCount() == 1));
    }

    private boolean isSelectStartGesture(GraphicsNodeEvent evt) {
        return (evt.getID() == GraphicsNodeMouseEvent.MOUSE_PRESSED);
    }

    private boolean isSelectEndGesture(GraphicsNodeEvent evt) {
        return ((evt.getID() == GraphicsNodeMouseEvent.MOUSE_RELEASED));
    }

    private boolean isSelectContinueGesture(GraphicsNodeEvent evt) {
        return (evt.getID() == GraphicsNodeMouseEvent.MOUSE_DRAGGED);
    }

    private boolean isSelectAllGesture(GraphicsNodeEvent evt) {
        return ((evt.getID() == GraphicsNodeMouseEvent.MOUSE_CLICKED)
            && (((GraphicsNodeMouseEvent) evt).getClickCount() == 2));
    }

    /*
     * Get the contents of the current selection.
     */
    public Object getSelection() {
        Object value = null;
        if (selectionNode instanceof Selectable) {
            value = ((Selectable) selectionNode).getSelection();
        }
        return value;
    }

    /**
     * Reports whether the current selection contains any objects.
     */
    public boolean isEmpty() {
        return (getSelection() == null);
    }

    /**
     * Reports whether the current selection contains any objects.
     */
    public void dispatchSelectionEvent(SelectionEvent e) {
        if (listeners != null) {
            Iterator iter = listeners.iterator();
            switch(e.getID()) {
            case SelectionEvent.SELECTION_DONE:
                while (iter.hasNext()) {
                    ((SelectionListener)iter.next()).selectionDone(e);
                }
                break;
            case SelectionEvent.SELECTION_CHANGED:
                while (iter.hasNext()) {
                    ((SelectionListener)iter.next()).selectionChanged(e);
                }
                break;
            case SelectionEvent.SELECTION_CLEARED:
                while (iter.hasNext()) {
                    ((SelectionListener)iter.next()).selectionCleared(e);
                }
                break;
            case SelectionEvent.SELECTION_STARTED:
                while (iter.hasNext()) {
                    ((SelectionListener)iter.next()).selectionStarted(e);
                }
                break;
            }
        }
    }

    /**
     * Add a SelectionListener to this Selector's notification list.
     * @param l the SelectionListener to add.
     */
    public void addSelectionListener(SelectionListener l) {
        if (listeners == null) {
            listeners = new ArrayList();
        }
        listeners.add(l);
    }

    /**
     * Remove a SelectionListener from this Selector's notification list.
     * @param l the SelectionListener to be removed.
     */
    public void removeSelectionListener(SelectionListener l) {
        if (listeners != null) {
            listeners.remove(l);
        }
    }

    private void report(GraphicsNodeEvent evt, String message) {
        GraphicsNode source = evt.getGraphicsNode();
        String label = "(non-text node)";
        if (source instanceof TextNode) {
            char[] cbuff;
            java.text.CharacterIterator iter =
                ((TextNode) source).getAttributedCharacterIterator();
            cbuff = new char[iter.getEndIndex()];
            if (cbuff.length > 0) cbuff[0] = iter.first();
            for (int i=1; i<cbuff.length;++i) {
                cbuff[i] = iter.next();
            }
            label = new String(cbuff);
        }
        System.out.println("Mouse "+message+" in "+label);
    }
}