/*

* Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  

*

*/

package com.nokia.helium.diamonds;

import java.io.File;

import java.io.FileOutputStream;

import java.util.Iterator;

import java.util.List;

import org.apache.log4j.Logger;

import org.dom4j.Attribute;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

/**

 * This class implements an XML file merger. All node from an external XML with

 * same format (same root node name) will get added to the source root element.

 */

public class XMLMerger {

    private Logger log = Logger.getLogger(getClass());

    private Document doc;

    private Element root;

    /**

     * Create an XMLMerger, the merge file will be used as input and output.

     * 

     * @param merge

     * @throws XMLMergerException

     */

        try {

            SAXReader reader = new SAXReader();

            root = doc.getRootElement();

        } catch (DocumentException e) {

            throw new XMLMergerException(e.getMessage());

        }        

    }

    /**

     * Add all sub element of data file into the merged file. If the root

     * element name is different for the merged file an XMLMergerException is

     * thrown.

     * 

     * @param data

     *            the input file.

     * @throws XMLMergerException

     */

    public void merge(File data) throws XMLMergerException {

        log.debug("Merging " + data.getAbsolutePath());

        try {

            SAXReader reader = new SAXReader();

            Document dataDoc = reader.read(data);

            Element dataRoot = dataDoc.getRootElement();

        } catch (DocumentException e) {

            throw new XMLMergerException(e.getMessage());

        }

    }

    /**

     * Merging two XML elements. It only keeps difference.

     * 

     * @param dest

     * @param src

     */

    @SuppressWarnings("unchecked")

    protected void mergeNode(Element dest, Element src) {

        for (Iterator<Element> node = src.elements().iterator(); node.hasNext();) {

            Element element = node.next();

            List<Element> ses = dest.elements(element.getName());

            boolean add = true;

            for (Element se : ses) {

                if (areSame(se, element)) {

                    log.debug("Element " + element.getName() + " already found in dest.");

                    add = false;

                }

            }

            if (add) {

                log.debug("Adding node " + element.getName() + " to " + dest.getName());

                dest.add(element.detach());

            } else if (ses.size() > 0) {

                log.debug("Merging " + ses.get(0).getName() + " to " + element.getName());

                mergeNode(ses.get(0), element);

            }

        }

    }

    /**

     * Compare two elements name and attributes. Returns true if name and all

     * attributes are matching, false otherwise.

     * 

     * @param a

     * @param b

     * @return boolean

     */

    @SuppressWarnings("unchecked")

    protected boolean areSame(Element a, Element b) {

        log.debug("areSame:" + a + " <=> " + b);

            return false;

        log.debug("same attribute list size?");

            return false;

        log.debug("same attribute list?");

        for (Iterator<Attribute> at = a.attributes().iterator(); at.hasNext();) {

            Attribute attra = at.next();

            Attribute attrb = b.attribute(attra.getName());

                return false;

        }

            return false;

        return true;

    }

    /**

     * Write the XML content back the file.

     * @throws XMLMergerException

     */

    protected void write() throws XMLMergerException {

        try {

            OutputFormat format = OutputFormat.createPrettyPrint();

            XMLWriter writer = new XMLWriter(fos, format);

            writer.write(doc);

            writer.flush();

        } catch (FileNotFoundException e) {

            throw new XMLMergerException(e.getMessage());

        } catch (UnsupportedEncodingException e) {

            throw new XMLMergerException(e.getMessage());

        } catch (IOException e) {

            throw new XMLMergerException(e.getMessage());

        }

    }

    /**

     * Exception class related to the XMLMerger. 

     */

    public class XMLMergerException extends Exception {

        private static final long serialVersionUID = 7624650310086957316L;

        /**

         * Default constructor.

         * @param msg error message

         */

        public XMLMergerException(String msg) {

            super(msg);

        }

    }

}