/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   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 .
 */

package ov;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;

import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JToggleButton;
import com.sun.star.accessibility.AccessibleEventId;
import com.sun.star.accessibility.AccessibleEventObject;
import com.sun.star.accessibility.AccessibleStateType;
import com.sun.star.accessibility.XAccessible;
import com.sun.star.accessibility.XAccessibleContext;
import com.sun.star.accessibility.XAccessibleSelection;
import com.sun.star.accessibility.XAccessibleStateSet;

import com.sun.star.uno.UnoRuntime;
import com.sun.star.lang.IndexOutOfBoundsException;


/** Display a list of children and select/deselect buttons
*/
class SelectionView
    extends ListeningObjectView
    implements ActionListener
{
    static public ObjectView Create (
        ObjectViewContainer aContainer,
        XAccessibleContext xContext)
    {
        XAccessibleSelection xSelection = UnoRuntime.queryInterface(
                XAccessibleSelection.class, xContext);
        if (xSelection != null)
            return new SelectionView(aContainer);
        else
            return null;
    }

    public SelectionView (ObjectViewContainer aContainer)
    {
        super (aContainer);
        Layout();
    }

    @Override
    public String GetTitle ()
    {
        return "Selection";
    }

    /** Create and arrange the widgets for this view.
    */
    private void Layout ()
    {
        setLayout (new GridBagLayout());

        GridBagConstraints aConstraints = new GridBagConstraints();

        // Label that shows wheter the selection is multi selectable.
        aConstraints.gridx = 0;
        aConstraints.gridy = 0;
        aConstraints.anchor = GridBagConstraints.WEST;
        maTypeLabel = new JLabel ();
        add (maTypeLabel, aConstraints);

        // the JListBox
        maChildrenSelector = new JPanel ();
        maChildrenSelector.setPreferredSize (new Dimension (100,100));
        maChildrenSelector.setLayout (new BoxLayout (maChildrenSelector, BoxLayout.Y_AXIS));

        aConstraints.gridx = 0;
        aConstraints.gridwidth = 4;
        aConstraints.gridy = 1;
        aConstraints.fill = GridBagConstraints.HORIZONTAL;
        add (new JScrollPane (maChildrenSelector,
                 JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
                 JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED),
            aConstraints);

        JButton aButton;
        aButton = new JButton( "Select all" );
        aButton.setActionCommand( "Select all" );
        aButton.addActionListener( this );
        aConstraints.gridx = 0;
        aConstraints.gridwidth = 1;
        aConstraints.gridy = 2;
        aConstraints.fill = GridBagConstraints.NONE;
        aConstraints.anchor = GridBagConstraints.WEST;
        add (aButton, aConstraints);

        aButton = new JButton( "Clear Selection" );
        aButton.setActionCommand( "Clear Selection" );
        aButton.addActionListener( this );
        aConstraints.gridx = 1;
        aConstraints.gridy = 2;
        aConstraints.weightx = 1;
        add (aButton, aConstraints);

        setSize (getPreferredSize());
    }


    @Override
    public void SetObject (XAccessibleContext xContext)
    {
        mxSelection = UnoRuntime.queryInterface(
            XAccessibleSelection.class, xContext);
        super.SetObject (xContext);
    }


    @Override
    public void Update ()
    {
        maChildrenSelector.removeAll ();

        // Determine whether multi selection is possible.
        XAccessibleStateSet aStateSet = mxContext.getAccessibleStateSet();
        boolean bMultiSelectable = false;
        ButtonGroup aButtonGroup = null;
        if (aStateSet!=null && aStateSet.contains(AccessibleStateType.MULTI_SELECTABLE))
        {
            bMultiSelectable = true;
            maTypeLabel.setText ("multi selectable");
        }
        else
        {
            maTypeLabel.setText ("single selectable");
            aButtonGroup = new ButtonGroup ();
        }

        int nCount = mxContext.getAccessibleChildCount();
        for (int i=0; i<nCount; i++)
        {
            try
            {
                XAccessible xChild = mxContext.getAccessibleChild(i);
                XAccessibleContext xChildContext = xChild.getAccessibleContext();

                String sName = i + " " + xChildContext.getAccessibleName();
                JToggleButton aChild;
                if (bMultiSelectable)
                    aChild = new JCheckBox (sName);
                else
                {
                    aChild = new JRadioButton (sName);
                    aButtonGroup.add (aChild);
                }

                XAccessibleStateSet aChildStateSet = mxContext.getAccessibleStateSet();
                aChild.setSelected (aChildStateSet!=null
                    && aChildStateSet.contains(AccessibleStateType.SELECTED));

                aChild.addActionListener (this);
                maChildrenSelector.add (aChild);

            }
            catch (IndexOutOfBoundsException e)
            {
            }
        }
    }


    void SelectAll()
    {
        mxSelection.selectAllAccessibleChildren();
    }

    void ClearSelection()
    {
        mxSelection.clearAccessibleSelection();
    }


    /** Call the function associated with the pressed button.
    */
    public void actionPerformed (ActionEvent aEvent)
    {
        String sCommand = aEvent.getActionCommand();

        if (sCommand.equals ("Clear Selection"))
            ClearSelection();
        else if (sCommand.equals ("Select all"))
            SelectAll();
        else
        {
            // Extract the child index from the widget text.
            String[] aWords = sCommand.split (" ");
            int nIndex = Integer.parseInt(aWords[0]);
            try
            {
                if (((JToggleButton)aEvent.getSource()).isSelected())
                    mxSelection.selectAccessibleChild (nIndex);
                else
                    mxSelection.deselectAccessibleChild (nIndex);
            }
            catch (IndexOutOfBoundsException e)
            {
                System.err.println ("caught exception while changing selection: " + e);
            }
        }
    }


    @Override
    public void notifyEvent (AccessibleEventObject aEvent)
    {
        if (aEvent.EventId == AccessibleEventId.SELECTION_CHANGED)
            Update ();
    }

    private JPanel maChildrenSelector;
    private XAccessibleSelection mxSelection;
    private JLabel maTypeLabel;
}