/*
 * 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 .
 */

import com.sun.star.accessibility.XAccessible;
import com.sun.star.accessibility.XAccessibleContext;
import com.sun.star.lang.IndexOutOfBoundsException;


/**
 * Map the tree of accessibility objects into their
 * AccessibilityTreeModel counterparts.
 */
class AccessibleTreeHandler
    extends NodeHandler
{
    private XAccessibleContext mxContext;

    @Override
    public NodeHandler createHandler (XAccessibleContext xContext)
    {
        if (xContext != null)
            return new AccessibleTreeHandler (xContext);
        else
            return null;
    }

    public AccessibleTreeHandler ()
    {
        super();
        mxContext = null;
    }

    private AccessibleTreeHandler (XAccessibleContext xContext)
    {
        super();
        mxContext = xContext;
        if (mxContext != null)
            // Add one to the number of children to include the string node
            // that tells you how many children there are.
            synchronized (maChildList)
            {
                maChildList.setSize (1 + mxContext.getAccessibleChildCount());
            }
    }

    @Override
    public AccessibleTreeNode createChild (AccessibleTreeNode aParent, int nIndex)
    {
        AccessibleTreeNode aChild = null;
        if (mxContext != null)
        {
            if (nIndex == 0)
                aChild = new StringNode ("Child count: " + mxContext.getAccessibleChildCount(),
                    aParent);
            else
            {
                // Lower index to skip the string node.
                nIndex -= 1;
                try
                {
                    XAccessible xChild = mxContext.getAccessibleChild (nIndex);
                    aChild = NodeFactory.Instance().createDefaultNode (
                        xChild, aParent);
                }
                catch( IndexOutOfBoundsException e )
                {
                    aChild = new StringNode ("ERROR: no child with index " + nIndex, aParent);
                }
            }
        }
        else
            aChild = new StringNode ("XAccessibleContext interface not supported", aParent);
        return aChild;
    }

    /** Try to add the specified accessible child into the lists of
        children.  The insertion position is determined from the
        getIndexInParent method of the child.
    */
    public AccessibleTreeNode addAccessibleChild (AccessibleTreeNode aParent, XAccessible xChild)
    {
        AccessibleTreeNode aChild = null;

        if (xChild != null)
        {
            XAccessibleContext xContext = xChild.getAccessibleContext();
            if (xContext != null)
            {
                long nIndex = xContext.getAccessibleIndexInParent() + 1;
                synchronized (maChildList)
                {
                    if ((nIndex >= 0) || (nIndex <= maChildList.size()))
                    {
                        aChild = NodeFactory.Instance().createDefaultNode (xChild, aParent);
                        maChildList.add (nIndex, aChild);
                    }
                }
            }
        }
        return aChild;
    }


    /** Update only the child count node.  Trust on other ways to update the
        accessible children.
    */
    @Override
    public void update (AccessibleTreeNode aNode)
    {
        synchronized (maChildList)
        {
            maChildList.set (0, null);
        }
    }
}
