/*
 * 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 org.openoffice.xmerge.converter.xml.sxc;

import org.w3c.dom.Node;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import org.openoffice.xmerge.Document;
import org.openoffice.xmerge.DocumentMerger;
import org.openoffice.xmerge.MergeException;
import org.openoffice.xmerge.ConverterCapabilities;
import org.openoffice.xmerge.converter.xml.OfficeConstants;
import org.openoffice.xmerge.merger.DiffAlgorithm;
import org.openoffice.xmerge.merger.Difference;
import org.openoffice.xmerge.merger.Iterator;
import org.openoffice.xmerge.merger.NodeMergeAlgorithm;
import org.openoffice.xmerge.merger.diff.IteratorRowCompare;
import org.openoffice.xmerge.merger.diff.RowIterator;
import org.openoffice.xmerge.merger.merge.SheetMerge;
import org.openoffice.xmerge.merger.merge.PositionBaseRowMerge;
import org.openoffice.xmerge.merger.MergeAlgorithm;
import org.openoffice.xmerge.util.XmlUtil;
import org.openoffice.xmerge.util.Debug;

/**
 * Generic small device implementation of {@code DocumentMerger} for
 * the {@link org.openoffice.xmerge.converter.xml.sxc.SxcPluginFactory
 * SxcPluginFactory}.
 *
 * <p>Used with SXC {@code Document} objects.</p>
 */
public class DocumentMergerImpl implements DocumentMerger {

    private final ConverterCapabilities cc_;
    private final org.openoffice.xmerge.Document orig;

    /**
     * Constructor.
     *
     * @param  doc  The original &quot;Office&quot; {@code Document} to merge.
     * @param  cc   The {@code ConverterCapabilities}.
     */
    public DocumentMergerImpl(org.openoffice.xmerge.Document doc,
            ConverterCapabilities cc) {
        cc_ = cc;
        this.orig = doc;
    }

    public void merge(Document modifiedDoc) throws MergeException {

        SxcDocument sdoc1 = (SxcDocument)orig;
        SxcDocument sdoc2 = (SxcDocument)modifiedDoc;

        org.w3c.dom.Document doc1 = sdoc1.getContentDOM();
        org.w3c.dom.Document doc2 = sdoc2.getContentDOM();

        Element elem1 = doc1.getDocumentElement();
        Element elem2 = doc2.getDocumentElement();

        // get table name
        NodeList workSheetList1 =
            elem1.getElementsByTagName(OfficeConstants.TAG_TABLE);
        NodeList workSheetList2 =
            elem2.getElementsByTagName(OfficeConstants.TAG_TABLE);

        int numOfWorkSheet = workSheetList1.getLength();

        for (int i=0; i < numOfWorkSheet; i++) {
            Node workSheet = workSheetList1.item(i);

            // try to match the workSheet
            Node matchingWorkSheet = matchWorkSheet(workSheet, workSheetList2);

            if (matchingWorkSheet != null) {

                // need to put it into a row Iterator
                // use a straight comparsion algorithm then do a merge on it
                Iterator i1 = new RowIterator(cc_, workSheet);
                Iterator i2 = new RowIterator(cc_, matchingWorkSheet);

                // find out the diff
                DiffAlgorithm diffAlgo = new IteratorRowCompare();

                // find out the paragrah level diffs
                Difference[] diffResult = diffAlgo.computeDiffs(i1, i2);

                if (Debug.isFlagSet(Debug.INFO)) {
                    Debug.log(Debug.INFO, "Diff Result: ");

                    for (int j = 0; j < diffResult.length; j++) {
                        Debug.log(Debug.INFO, diffResult[j].debug());
                    }
                }

                // merge back the result
                NodeMergeAlgorithm rowMerger = new PositionBaseRowMerge(cc_);
                MergeAlgorithm merger = new SheetMerge(cc_, rowMerger);

                merger.applyDifference(i1, i2, diffResult);
            }
        }

        numOfWorkSheet = workSheetList2.getLength();

        // for those workSheet from target don't have a matching one in the
        // original workSheet list, we add it

        // find out the office body node first
        NodeList officeBodyList =
            elem1.getElementsByTagName(OfficeConstants.TAG_OFFICE_BODY);

        Node officeBody = officeBodyList.item(0);

        // for each WorkSheets, try to see whether we have it or not
        for (int j=0; j < numOfWorkSheet; j++) {
            Node workSheet= workSheetList2.item(j);

            // try to match the workSheet
            Node matchingWorkSheet = matchWorkSheet(workSheet, workSheetList1);

            // add the new WorkSheet to the original document iff match not found
            if (matchingWorkSheet == null) {
                Node cloneNode = XmlUtil.deepClone(officeBody, workSheet);
                officeBody.appendChild(cloneNode);
            }
        }
    }

    /**
     * Try to find a WorkSheet from the modified WorkSheetList that has a
     * matching table name from the original WorkSheet.
     *
     * @param   orgSheet      The original WorkSheet.
     * @param   modSheetList  The modified WorkSheet.
     *
     * @return  The {@code Node} in modSheetList that matches the {@code orgSheet}.
     */
    private Node matchWorkSheet(Node orgSheet, NodeList modSheetList) {

        Node matchSheet = null;

        String orgTableName = ((Element)orgSheet).getAttribute(
                            OfficeConstants.ATTRIBUTE_TABLE_NAME);

        if (orgTableName == null)
            return null;

        int numOfWorkSheet = modSheetList.getLength();

        String modTableName;

        for (int i=0; i < numOfWorkSheet; i++) {
            modTableName = ((Element)modSheetList.item(i)).getAttribute(
                            OfficeConstants.ATTRIBUTE_TABLE_NAME);
            if (modTableName == null)
                continue;

            if (orgTableName.equals(modTableName)) {
                matchSheet = modSheetList.item(i);
                break;
            }
        }

        return matchSheet;
    }
}