/* ====================================================================
   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.poi.hssf.model;

import static org.apache.logging.log4j.util.Unbox.box;

import java.security.AccessControlException;
import java.util.*;
import java.util.Map.Entry;

import org.apache.logging.log4j.Logger;
import org.apache.poi.logging.PoiLogManager;
import org.apache.poi.ddf.EscherBSERecord;
import org.apache.poi.ddf.EscherBoolProperty;
import org.apache.poi.ddf.EscherContainerRecord;
import org.apache.poi.ddf.EscherDgRecord;
import org.apache.poi.ddf.EscherDggRecord;
import org.apache.poi.ddf.EscherOptRecord;
import org.apache.poi.ddf.EscherPropertyTypes;
import org.apache.poi.ddf.EscherRGBProperty;
import org.apache.poi.ddf.EscherRecord;
import org.apache.poi.ddf.EscherSimpleProperty;
import org.apache.poi.ddf.EscherSpRecord;
import org.apache.poi.ddf.EscherSplitMenuColorsRecord;
import org.apache.poi.hssf.extractor.OldExcelExtractor;
import org.apache.poi.hssf.record.*;
import org.apache.poi.hssf.record.Record;
import org.apache.poi.hssf.record.common.UnicodeString;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.HSSFColor.HSSFColorPredefined;
import org.apache.poi.poifs.crypt.CryptoFunctions;
import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalName;
import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheet;
import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheetRange;
import org.apache.poi.ss.formula.FormulaShifter;
import org.apache.poi.ss.formula.ptg.Area3DPtg;
import org.apache.poi.ss.formula.ptg.NameXPtg;
import org.apache.poi.ss.formula.ptg.OperandPtg;
import org.apache.poi.ss.formula.ptg.Ptg;
import org.apache.poi.ss.formula.ptg.Ref3DPtg;
import org.apache.poi.ss.formula.udf.UDFFinder;
import org.apache.poi.ss.usermodel.BuiltinFormats;
import org.apache.poi.ss.usermodel.SheetVisibility;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.util.Internal;
import org.apache.poi.util.LocaleUtil;
import org.apache.poi.util.RecordFormatException;

/**
 * Low level model implementation of a Workbook.  Provides creational methods
 * for settings and objects contained in the workbook object.
 * <P>
 * This file contains the low level binary records starting at the workbook's BOF and
 * ending with the workbook's EOF.  Use HSSFWorkbook for a high level representation.
 * <P>
 * The structures of the highlevel API use references to this to perform most of their
 * operations.  Its probably unwise to use these low level structures directly unless you
 * really know what you're doing.  I recommend you read the Microsoft Excel 97 Developer's
 * Kit (Microsoft Press) and the documentation at https://sc.openoffice.org/excelfileformat.pdf
 * before even attempting to use this.
 *
 * @see HSSFWorkbook
 */
@Internal
public final class InternalWorkbook {
    /**
     * Excel silently truncates long sheet names to 31 chars.
     * This constant is used to ensure uniqueness in the first 31 chars
     */
    private static final int MAX_SENSITIVE_SHEET_NAME_LEN = 31;

    /**
     * Normally, the Workbook will be in a POIFS Stream called
     *  "Workbook". However, some weird XLS generators use "WORKBOOK"
     *  or "BOOK". This includes common case sensitive variations.
     */
    public static final List<String> WORKBOOK_DIR_ENTRY_NAMES = Collections.unmodifiableList(
            Arrays.asList(
                    "Workbook", // as per BIFF8 spec
                    "WORKBOOK", // Typically from third party programs
                    "BOOK",     // Typically odd Crystal Reports exports
                    "WorkBook"  // Another third party program special
            )
    );

    /**
     *     Crystal exports may use this for a regular .xls file. This
     *     needs to be distinguished case sensitively from {@link #OLD_WORKBOOK_DIR_ENTRY_NAME}.
     */
    public static final String BOOK = "BOOK";

    public static final String WORKBOOK = "WORKBOOK";

    public static final List<String> WORKBOOK_DIR_ENTRY_NAMES_CASE_INSENSITIVE =
            Collections.unmodifiableList(
                    Arrays.asList(WORKBOOK, BOOK)
    );

    /**
     * Name of older (pre-Excel 97) Workbook streams, which
     *  aren't supported by HSSFWorkbook, only by
     *  {@link OldExcelExtractor}
     */
    public static final String OLD_WORKBOOK_DIR_ENTRY_NAME = "Book";

    private static final Logger LOG = PoiLogManager.getLogger(InternalWorkbook.class);

    /**
     * constant used to set the "codepage" wherever "codepage" is set in records
     * (which is duplicated in more than one record)
     */
    private static final short CODEPAGE = 0x04B0;

    /**
     * this contains the Worksheet record objects
     */
    private final WorkbookRecordList records;

    /**
     * this contains a reference to the SSTRecord so that new stings can be added
     * to it.
     */
    protected SSTRecord sst;


    private LinkTable linkTable; // optionally occurs if there are  references in the document. (4.10.3)

    /**
     * holds the "boundsheet" records (aka bundlesheet) so that they can have their
     * reference to their "BOF" marker
     */
    private final List<BoundSheetRecord> boundsheets;
    private final List<FormatRecord> formats;
    private final List<HyperlinkRecord> hyperlinks;

    /** the number of extended format records */
    private int numxfs;
    /** the number of font records */
    private int numfonts;
    /** holds the max format id */
    private int maxformatid;
    /** whether 1904 date windowing is being used */
    private boolean uses1904datewindowing;
    private DrawingManager2 drawingManager;
    private final List<EscherBSERecord> escherBSERecords;
    private WindowOneRecord windowOne;
    private FileSharingRecord fileShare;
    private WriteAccessRecord writeAccess;
    private WriteProtectRecord writeProtect;

    /**
     * Hold the {@link NameCommentRecord}s indexed by the name of the {@link NameRecord} to which they apply.
     */
    private final Map<String, NameCommentRecord> commentRecords;

    private InternalWorkbook() {
        records     = new WorkbookRecordList();

        boundsheets = new ArrayList<>();
        formats = new ArrayList<>();
        hyperlinks = new ArrayList<>();
        numxfs = 0;
        numfonts = 0;
        maxformatid = -1;
        uses1904datewindowing = false;
        escherBSERecords = new ArrayList<>();
        commentRecords = new LinkedHashMap<>();
    }

    /**
     * read support  for low level
     * API.  Pass in an array of Record objects, A Workbook
     * object is constructed and passed back with all of its initialization set
     * to the passed in records and references to those records held. Unlike Sheet
     * workbook does not use an offset (its assumed to be 0) since its first in a file.
     * If you need an offset then construct a new array with a 0 offset or write your
     * own ;-p.
     *
     * @param recs an array of Record objects
     * @return Workbook object
     */
    public static InternalWorkbook createWorkbook(List<Record> recs) {
        LOG.atDebug().log("Workbook (readfile) created with reclen={}", box(recs.size()));
        InternalWorkbook retval = new InternalWorkbook();
        List<Record> records = new ArrayList<>(recs.size() / 3);
        retval.records.setRecords(records);

        boolean eofPassed = false;
        for (int k = 0; k < recs.size(); k++) {
            Record rec = recs.get(k);
            String logObj;
            switch (rec.getSid()) {

                case EOFRecord.sid :
                    logObj = "workbook eof";
                    break;

                case BoundSheetRecord.sid :
                    logObj = "boundsheet";
                    retval.boundsheets.add((BoundSheetRecord) rec);
                    retval.records.setBspos( k );
                    break;

                case SSTRecord.sid :
                    logObj = "sst";
                    retval.sst = ( SSTRecord ) rec;
                    break;

                case FontRecord.sid :
                    logObj = "font";
                    retval.records.setFontpos( k );
                    retval.numfonts++;
                    break;

                case ExtendedFormatRecord.sid :
                    logObj = "XF";
                    retval.records.setXfpos( k );
                    retval.numxfs++;
                    break;

                case TabIdRecord.sid :
                    logObj = "tabid";
                    retval.records.setTabpos( k );
                    break;

                case ProtectRecord.sid :
                    logObj = "protect";
                    retval.records.setProtpos( k );
                    break;

                case BackupRecord.sid :
                    logObj = "backup";
                    retval.records.setBackuppos( k );
                    break;

                case ExternSheetRecord.sid :
                    throw new RecordFormatException("Extern sheet is part of LinkTable");

                case NameRecord.sid :
                case SupBookRecord.sid :
                    // LinkTable can start with either of these
                    LOG.atDebug().log("found SupBook record at {}", box(k));
                    retval.linkTable = new LinkTable(recs, k, retval.records, retval.commentRecords);
                    k+=retval.linkTable.getRecordCount() - 1;
                    continue;

                case FormatRecord.sid :
                    logObj = "format";
                    FormatRecord fr = (FormatRecord) rec;
                    retval.formats.add(fr);
                    retval.maxformatid = Math.max(retval.maxformatid, fr.getIndexCode());
                    break;

                case DateWindow1904Record.sid :
                    logObj = "datewindow1904";
                    retval.uses1904datewindowing = ((DateWindow1904Record)rec).getWindowing() == 1;
                    break;

                case PaletteRecord.sid:
                    logObj = "palette";
                    retval.records.setPalettepos( k );
                    break;

                case WindowOneRecord.sid:
                    logObj = "WindowOneRecord";
                    retval.windowOne = (WindowOneRecord) rec;
                    break;

                case WriteAccessRecord.sid:
                    logObj = "WriteAccess";
                    retval.writeAccess = (WriteAccessRecord) rec;
                    break;

                case WriteProtectRecord.sid:
                    logObj = "WriteProtect";
                    retval.writeProtect = (WriteProtectRecord) rec;
                    break;

                case FileSharingRecord.sid:
                    logObj = "FileSharing";
                    retval.fileShare = (FileSharingRecord) rec;
                    break;

                case NameCommentRecord.sid:
                    logObj = "NameComment";
                    final NameCommentRecord ncr = (NameCommentRecord) rec;
                    retval.commentRecords.put(ncr.getNameText(), ncr);
                    break;

                case HyperlinkRecord.sid:
                    // Look for other interesting values that follow the EOFRecord
                    logObj = "Hyperlink";
                    retval.hyperlinks.add((HyperlinkRecord)rec);
                    break;

                default:
                    logObj = "(sid=" + rec.getSid() + ")";
                    break;
            }
            if (!eofPassed) {
                records.add(rec);
            }
            LOG.atTrace().log("found {} record at {}", logObj, box(k));
            if (rec.getSid() == EOFRecord.sid) {
                eofPassed = true;
            }
        }
        //What if we dont have any ranges and supbooks
        //        if (retval.records.supbookpos == 0) {
        //            retval.records.supbookpos = retval.records.bspos + 1;
        //            retval.records.namepos    = retval.records.supbookpos + 1;
        //        }

        if (retval.windowOne == null) {
            retval.windowOne = createWindowOne();
        }
        LOG.atDebug().log("exit create workbook from existing file function");
        return retval;
    }

    /**
     * Creates an empty workbook object with three blank sheets and all the empty
     * fields.  Use this to create a workbook from scratch.
     *
     * @return an empty workbook object
     */
    public static InternalWorkbook createWorkbook() {
        LOG.atDebug().log("creating new workbook from scratch");

        InternalWorkbook retval = new InternalWorkbook();
        List<Record> records = new ArrayList<>(30);
        retval.records.setRecords(records);
        List<FormatRecord> formats = retval.formats;

        records.add(createBOF());
        records.add(new InterfaceHdrRecord(CODEPAGE));
        records.add(createMMS());
        records.add(InterfaceEndRecord.instance);
        // store the write-access record at the proper position
        retval.getWriteAccess();
        records.add(createCodepage());
        records.add(createDSF());
        records.add(createTabId());
        retval.records.setTabpos(records.size() - 1);
        records.add(createFnGroupCount());
        records.add(createWindowProtect());
        records.add(createProtect());
        retval.records.setProtpos(records.size() - 1);
        records.add(createPassword());
        records.add(createProtectionRev4());
        records.add(createPasswordRev4());
        retval.windowOne = createWindowOne();
        records.add(retval.windowOne);
        records.add(createBackup());
        retval.records.setBackuppos(records.size() - 1);
        records.add(createHideObj());
        records.add(createDateWindow1904());
        records.add(createPrecision());
        records.add(createRefreshAll());
        records.add(createBookBool());
        records.add(createFont());
        records.add(createFont());
        records.add(createFont());
        records.add(createFont());
        retval.records.setFontpos( records.size() - 1 );   // last font record position
        retval.numfonts = 4;

        // set up format records
        for (int i = 0; i <= 7; i++) {
            FormatRecord rec = createFormat(i);
            retval.maxformatid = Math.max(retval.maxformatid, rec.getIndexCode());
            formats.add(rec);
            records.add(rec);
        }

        for (int k = 0; k < 21; k++) {
            records.add(InternalWorkbook.createExtendedFormat(k));
            retval.numxfs++;
        }
        retval.records.setXfpos( records.size() - 1 );
        for (int k = 0; k < 6; k++) {
            records.add(InternalWorkbook.createStyle(k));
        }
        records.add(InternalWorkbook.createUseSelFS());

        int nBoundSheets = 1; // now just do 1
        for (int k = 0; k < nBoundSheets; k++) {
            BoundSheetRecord bsr = createBoundSheet(k);

            records.add(bsr);
            retval.boundsheets.add(bsr);
            retval.records.setBspos(records.size() - 1);
        }
        records.add( InternalWorkbook.createCountry() );
        for ( int k = 0; k < nBoundSheets; k++ ) {
            retval.getOrCreateLinkTable().checkExternSheet(k);
        }
        retval.sst = new SSTRecord();
        records.add(retval.sst);
        records.add(InternalWorkbook.createExtendedSST());

        records.add(EOFRecord.instance);
        LOG.atDebug().log("exit create new workbook from scratch");

        return retval;
    }


    /**Retrieves the Builtin NameRecord that matches the name and index
     * There shouldn't be too many names to make the sequential search too slow
     * @param name byte representation of the builtin name to match
     * @param sheetNumber 1-based sheet number
     * @return null if no builtin NameRecord matches
     */
    public NameRecord getSpecificBuiltinRecord(byte name, int sheetNumber)
    {
        return getOrCreateLinkTable().getSpecificBuiltinRecord(name, sheetNumber);
    }

    /**
     * Removes the specified Builtin NameRecord that matches the name and index
     * @param name byte representation of the builtin to match
     * @param sheetIndex zero-based sheet reference
     */
    public void removeBuiltinRecord(byte name, int sheetIndex) {
        linkTable.removeBuiltinRecord(name, sheetIndex);
        // TODO - do we need "this.records.remove(...);" similar to that in this.removeName(int namenum) {}?
    }

    public int getNumRecords() {
        return records.size();
    }

    /**
     * gets the font record at the given index in the font table.  Remember
     * "There is No Four" (someone at M$ must have gone to Rocky Horror one too
     * many times)
     *
     * @param idx the index to look at (0 or greater but NOT 4)
     * @return FontRecord located at the given index
     */

    public FontRecord getFontRecordAt(int idx) {
        int index = idx;

        if (index > 4) {
            index -= 1;   // adjust for "There is no 4"
        }
        if (index > (numfonts - 1)) {
            throw new ArrayIndexOutOfBoundsException(
            "There are only " + numfonts + " font records, but you asked for index " + idx);
        }

        Record record = records.get((records.getFontpos() - (numfonts - 1)) + index);
        if (!(record instanceof FontRecord)) {
            throw new IllegalStateException("Did not have the expected record-type FontRecord: " + record.getClass());
        }
        return ( FontRecord ) record;
    }

    /**
     * Retrieves the index of the given font
     *
     * @param font the font
     *
     * @return the font index
     *
     * @throws IllegalArgumentException if the font index can't be determined
     */
    public int getFontIndex(FontRecord font) {
        for(int i=0; i<=numfonts; i++) {
            FontRecord thisFont =
                ( FontRecord ) records.get((records.getFontpos() - (numfonts - 1)) + i);
            if(thisFont == font) {
                // There is no 4!
                return (i > 3) ? i+1 : i;
            }
        }
        throw new IllegalArgumentException("Could not find that font!");
    }

    /**
     * creates a new font record and adds it to the "font table".  This causes the
     * boundsheets to move down one, extended formats to move down (so this function moves
     * those pointers as well)
     *
     * @return FontRecord that was just created
     */

    public FontRecord createNewFont() {
        FontRecord rec = createFont();

        records.add(records.getFontpos()+1, rec);
        records.setFontpos( records.getFontpos() + 1 );
        numfonts++;
        return rec;
    }

    /**
     * Removes the given font record from the
     *  file's list. This will make all
     *  subsequent font indicies drop by one,
     *  so you'll need to update those yourself!
     *
     * @param rec the font record
     */
    public void removeFontRecord(FontRecord rec) {
        records.remove(rec); // this updates FontPos for us
        numfonts--;
    }

    /**
     * gets the number of font records
     *
     * @return   number of font records in the "font table"
     */

    public int getNumberOfFontRecords() {
        return numfonts;
    }

    /**
     * Sets the BOF for a given sheet
     *
     * @param sheetIndex the number of the sheet to set the positing of the bof for
     * @param pos the actual bof position
     */

    public void setSheetBof(int sheetIndex, int pos) {
        LOG.atDebug().log("setting bof for sheetnum ={} at pos={}", box(sheetIndex),box(pos));

        checkSheets(sheetIndex);
        getBoundSheetRec(sheetIndex)
        .setPositionOfBof(pos);
    }

    private BoundSheetRecord getBoundSheetRec(int sheetIndex) {
        return boundsheets.get(sheetIndex);
    }

    /**
     * Returns the position of the backup record.
     *
     * @return the position of the backup record
     */
    public BackupRecord getBackupRecord() {
        return ( BackupRecord ) records.get(records.getBackuppos());
    }


    /**
     * sets the name for a given sheet.  If the boundsheet record doesn't exist and
     * its only one more than we have, go ahead and create it.  If it's &gt; 1 more than
     * we have, except
     *
     * @param sheetnum the sheet number (0 based)
     * @param sheetname the name for the sheet
     */
    public void setSheetName(int sheetnum, final String sheetname) {
        checkSheets(sheetnum);

        // YK: Mimic Excel and silently truncate sheet names longer than 31 characters
        String sn = (sheetname.length() > 31) ? sheetname.substring(0, 31) : sheetname;

        BoundSheetRecord sheet = boundsheets.get(sheetnum);
        sheet.setSheetname(sn);
    }

    /**
     * Determines whether a workbook contains the provided sheet name.  For the purpose of
     * comparison, long names are truncated to 31 chars.
     *
     * @param name the name to test (case insensitive match)
     * @param excludeSheetIdx the sheet to exclude from the check or -1 to include all sheets in the check.
     * @return true if the sheet contains the name, false otherwise.
     */
    public boolean doesContainsSheetName(String name, int excludeSheetIdx) {
        String aName = name;
        if (aName.length() > MAX_SENSITIVE_SHEET_NAME_LEN) {
            aName = aName.substring(0, MAX_SENSITIVE_SHEET_NAME_LEN);
        }
        int i=0;
        for (BoundSheetRecord boundSheetRecord : boundsheets) {
            if (excludeSheetIdx == i++) {
                continue;
            }
            String bName = boundSheetRecord.getSheetname();
            if (bName.length() > MAX_SENSITIVE_SHEET_NAME_LEN) {
                bName = bName.substring(0, MAX_SENSITIVE_SHEET_NAME_LEN);
            }
            if (aName.equalsIgnoreCase(bName)) {
                return true;
            }
        }
        return false;
    }

    /**
     * sets the order of appearance for a given sheet.
     *
     * @param sheetname the name of the sheet to reorder
     * @param pos the position that we want to insert the sheet into (0 based)
     */
    public void setSheetOrder(String sheetname, int pos ) {
        int sheetNumber = getSheetIndex(sheetname);
        //remove the sheet that needs to be reordered and place it in the spot we want
        boundsheets.add(pos, boundsheets.remove(sheetNumber));

        // also adjust order of Records, calculate the position of the Boundsheets via getBspos()...
        int initialBspos = records.getBspos();
        int pos0 = initialBspos - (boundsheets.size() - 1);
        Record removed = records.get(pos0 + sheetNumber);
        records.remove(pos0 + sheetNumber);
        records.add(pos0 + pos, removed);
        records.setBspos(initialBspos);
    }

    /**
     * gets the name for a given sheet.
     *
     * @param sheetIndex the sheet number (0 based)
     * @return sheetname the name for the sheet
     */
    public String getSheetName(int sheetIndex) {
        return getBoundSheetRec(sheetIndex).getSheetname();
    }

    /**
     * Gets the hidden flag for a given sheet.
     * Note that a sheet could instead be
     *  set to be very hidden, which is different
     *  ({@link #isSheetVeryHidden(int)})
     *
     * @param sheetnum the sheet number (0 based)
     * @return True if sheet is hidden
     */
    public boolean isSheetHidden(int sheetnum) {
        return getBoundSheetRec(sheetnum).isHidden();
    }

    /**
     * Gets the very hidden flag for a given sheet.
     * This is different from the normal
     *  hidden flag
     *  ({@link #isSheetHidden(int)})
     *
     * @param sheetnum the sheet number (0 based)
     * @return True if sheet is very hidden
     */
    public boolean isSheetVeryHidden(int sheetnum) {
        return getBoundSheetRec(sheetnum).isVeryHidden();
    }

    /**
     * Gets the hidden flag for a given sheet.
     * Note that a sheet could instead be
     *  set to be very hidden, which is different
     *  ({@link #isSheetVeryHidden(int)})
     *
     * @param sheetnum the sheet number (0 based)
     * @return True if sheet is hidden
     * @since 3.16 beta 2
     */
    public SheetVisibility getSheetVisibility(int sheetnum) {
        final BoundSheetRecord bsr = getBoundSheetRec(sheetnum);
        if (bsr.isVeryHidden()) {
            return SheetVisibility.VERY_HIDDEN;
        }
        if (bsr.isHidden()) {
            return SheetVisibility.HIDDEN;
        }
        return SheetVisibility.VISIBLE;
    }

    /**
     * Hide or unhide a sheet
     *
     * @param sheetnum The sheet number
     * @param hidden True to mark the sheet as hidden, false otherwise
     */
    public void setSheetHidden(int sheetnum, boolean hidden) {
        setSheetHidden(sheetnum, hidden ? SheetVisibility.HIDDEN : SheetVisibility.VISIBLE);
    }

    /**
     * Hide or unhide a sheet.
     *
     * @param sheetnum   The sheet number
     * @param visibility the sheet visibility to set (visible, hidden, very hidden)
     * @since 3.16 beta 2
     */
    public void setSheetHidden(int sheetnum, SheetVisibility visibility) {
        checkSheets(sheetnum);

        BoundSheetRecord bsr = getBoundSheetRec(sheetnum);
        bsr.setHidden(visibility == SheetVisibility.HIDDEN);
        bsr.setVeryHidden(visibility == SheetVisibility.VERY_HIDDEN);
    }


    /**
     * get the sheet's index
     * @param name  sheet name
     * @return sheet index or -1 if it was not found.
     */
    public int getSheetIndex(String name) {
        int retval = -1;

        final int size = boundsheets.size();
        for (int k = 0; k < size; k++) {
            String sheet = getSheetName(k);

            if (sheet.equalsIgnoreCase(name)) {
                retval = k;
                break;
            }
        }
        return retval;
    }

    /**
     * if we're trying to address one more sheet than we have, go ahead and add it!  if we're
     * trying to address >1 more than we have throw an exception!
     */
    private void checkSheets(int sheetnum) {
        if ((boundsheets.size()) <= sheetnum) {   // if we're short one add another..
            if ((boundsheets.size() + 1) <= sheetnum) {
                throw new IllegalStateException("Sheet number out of bounds!");
            }
            BoundSheetRecord bsr = createBoundSheet(sheetnum);

            records.add(records.getBspos()+1, bsr);
            records.setBspos( records.getBspos() + 1 );
            boundsheets.add(bsr);
            getOrCreateLinkTable().checkExternSheet(sheetnum);
            fixTabIdRecord();
        }
    }

    /**
     * @param sheetIndex zero based sheet index
     */
    public void removeSheet(int sheetIndex) {
        if (boundsheets.size() > sheetIndex) {
            records.remove(records.getBspos() - (boundsheets.size() - 1) + sheetIndex);
            boundsheets.remove(sheetIndex);
            fixTabIdRecord();
        }

        // Within NameRecords, it's ok to have the formula
        //  part point at deleted sheets. It's also ok to
        //  have the ExternSheetNumber point at deleted
        //  sheets.
        // However, the sheet index must be adjusted, or
        //  excel will break. (Sheet index is either 0 for
        //  global, or 1 based index to sheet)
        int sheetNum1Based = sheetIndex + 1;
        for(int i=0; i<getNumNames(); i++) {
            NameRecord nr = getNameRecord(i);

            if(nr.getSheetNumber() == sheetNum1Based) {
                // Excel re-writes these to point to no sheet
                nr.setSheetNumber(0);
            } else if(nr.getSheetNumber() > sheetNum1Based) {
                // Bump down by one, so still points
                //  at the same sheet
                nr.setSheetNumber(nr.getSheetNumber()-1);
            }
        }

        if (linkTable != null) {
            // also tell the LinkTable about the removed sheet
            //index hasn't change in the linktable
            linkTable.removeSheet(sheetIndex);
        }
    }

    /**
     * make the tabid record look like the current situation.
     */
    private void fixTabIdRecord() {

        // see bug 55982, quite a number of documents do not have a TabIdRecord and
        // thus there is no way to do the fixup here,
        // we use the same check on Tabpos as done in other places
        if(records.getTabpos() <= 0) {
            return;
        }

        Record rec = records.get(records.getTabpos());

        TabIdRecord tir = ( TabIdRecord ) rec;
        short[]     tia = new short[ boundsheets.size() ];

        for (short k = 0; k < tia.length; k++) {
            tia[ k ] = k;
        }
        tir.setTabIdArray(tia);
    }

    /**
     * returns the number of boundsheet objects contained in this workbook.
     *
     * @return number of BoundSheet records
     */

    public int getNumSheets() {
        LOG.atDebug().log("getNumSheets={}", box(boundsheets.size()));
        return boundsheets.size();
    }

    /**
     * get the number of ExtendedFormat records contained in this workbook.
     *
     * @return int count of ExtendedFormat records
     */

    public int getNumExFormats() {
        LOG.atDebug().log("getXF={}", box(numxfs));
        return numxfs;
    }

    /**
     * gets the ExtendedFormatRecord at the given 0-based index
     *
     * @param index of the Extended format record (0-based)
     * @return ExtendedFormatRecord at the given index
     */

    public ExtendedFormatRecord getExFormatAt(int index) {
        int xfptr = records.getXfpos() - (numxfs - 1);

        xfptr += index;

        Record record = records.get(xfptr);
        if (!(record instanceof ExtendedFormatRecord)) {
            throw new IllegalStateException("Did not have a ExtendedFormatRecord: " + record);
        }
        return (ExtendedFormatRecord) record;
    }

    /**
     * Removes the given ExtendedFormatRecord record from the
     *  file's list. This will make all
     *  subsequent font indicies drop by one,
     *  so you'll need to update those yourself!
     *
     * @param rec the ExtendedFormatRecord
     */
    public void removeExFormatRecord(ExtendedFormatRecord rec) {
        records.remove(rec); // this updates XfPos for us
        numxfs--;
    }

    /**
     * Removes ExtendedFormatRecord record with given index from the
     *  file's list. This will make all
     *  subsequent font indicies drop by one,
     *  so you'll need to update those yourself!
     *  @param index of the Extended format record (0-based)
     */
    public void removeExFormatRecord(int index) {
        int xfptr = records.getXfpos() - (numxfs - 1) + index;
        records.remove(xfptr); // this updates XfPos for us
        numxfs--;
    }


    /**
     * creates a new Cell-type Extended Format Record and adds it to the end of
     *  ExtendedFormatRecords collection
     *
     * @return ExtendedFormatRecord that was created
     */

    public ExtendedFormatRecord createCellXF() {
        ExtendedFormatRecord xf = createExtendedFormat();

        records.add(records.getXfpos()+1, xf);
        records.setXfpos( records.getXfpos() + 1 );
        numxfs++;
        return xf;
    }

    /**
     * Returns the StyleRecord for the given
     *  xfIndex, or null if that ExtendedFormat doesn't
     *  have a Style set.
     *
     * @param xfIndex the extended format index
     *
     * @return the StyleRecord, {@code null} if it that ExtendedFormat doesn't have a Style set.
     */
    public StyleRecord getStyleRecord(int xfIndex) {
        // Style records always follow after
        //  the ExtendedFormat records
        for(int i=records.getXfpos(); i<records.size(); i++) {
            Record r = records.get(i);
            if (r instanceof StyleRecord) {
                StyleRecord sr = (StyleRecord)r;
                if (sr.getXFIndex() == xfIndex) {
                    return sr;
                }
            }
        }
        return null;
    }

    /**
     * Update the StyleRecord to point to the new
     * given index.
     *
     * @param oldXf the extended format index that was previously associated with this StyleRecord
     * @param newXf the extended format index that is now associated with this StyleRecord
     */
    public void updateStyleRecord(int oldXf, int newXf) {
        // Style records always follow after
        //  the ExtendedFormat records
        for(int i=records.getXfpos(); i<records.size(); i++) {
            Record r = records.get(i);
            if (r instanceof StyleRecord) {
                StyleRecord sr = (StyleRecord)r;
                if (sr.getXFIndex() == oldXf) {
                    sr.setXFIndex(newXf);
                }
            }
        }
    }

    /**
     * Creates a new StyleRecord, for the given Extended
     *  Format index, and adds it onto the end of the
     *  records collection
     *
     * @param xfIndex the extended format index
     *
     * @return a new StyleRecord
     */
    public StyleRecord createStyleRecord(int xfIndex) {
        // Style records always follow after
        //  the ExtendedFormat records
        StyleRecord newSR = new StyleRecord();
        newSR.setXFIndex(xfIndex);

        // Find the spot
        int addAt = -1;
        for(int i=records.getXfpos(); i<records.size() &&
                addAt == -1; i++) {
            Record r = records.get(i);
            if(r instanceof ExtendedFormatRecord ||
                    r instanceof StyleRecord) {
                // Keep going
            } else {
                addAt = i;
            }
        }
        if(addAt == -1) {
            throw new IllegalStateException("No XF Records found!");
        }
        records.add(addAt, newSR);

        return newSR;
    }

    /**
     * Adds a string to the SST table and returns its index (if its a duplicate
     * just returns its index and update the counts) ASSUMES compressed unicode
     * (meaning 8bit)
     *
     * @param string the string to be added to the SSTRecord
     *
     * @return index of the string within the SSTRecord
     */

    public int addSSTString(UnicodeString string) {
        LOG.atDebug().log("insert to sst string='{}'", string);
        if (sst == null) {
            insertSST();
        }
      return sst.addString(string);
    }

    /**
     * given an index into the SST table, this function returns the corresponding String value
     * @param str the index into the SST table
     * @return String containing the SST String
     */
    public UnicodeString getSSTString(int str) {
        if (sst == null) {
            insertSST();
        }
        UnicodeString retval = sst.getString(str);

        LOG.atTrace().log("Returning SST for index={} String= {}", box(str), retval);
        return retval;
    }

    /**
     * use this function to add a Shared String Table to an existing sheet (say
     * generated by a different java api) without an sst....
     * @see #createExtendedSST()
     * @see SSTRecord
     */

    public void insertSST() {
        LOG.atDebug().log("creating new SST via insertSST!");

        sst = new SSTRecord();
        records.add(records.size() - 1, createExtendedSST());
        records.add(records.size() - 2, sst);
    }

    /**
     * Serializes all records int the worksheet section into a big byte array. Use
     * this to write the Workbook out.
     * @param offset of the data to be written
     * @param data array of bytes to write this to
     * @return the length of serialized bytes
     */
    public int serialize( int offset, byte[] data ) {
        LOG.atDebug().log("Serializing Workbook with offsets");

        int pos = 0;

        SSTRecord lSST = null;
        int sstPos = 0;
        boolean wroteBoundSheets = false;
        for ( Record record : records.getRecords() ) {
            int len = 0;
            if (record instanceof SSTRecord) {
                lSST = (SSTRecord)record;
                sstPos = pos;
            }
            if (record.getSid() == ExtSSTRecord.sid && lSST != null) {
                record = lSST.createExtSSTRecord(sstPos + offset);
            }
            if (record instanceof BoundSheetRecord) {
                 if(!wroteBoundSheets) {
                    for (BoundSheetRecord bsr : boundsheets) {
                        len += bsr.serialize(pos+offset+len, data);
                    }
                    wroteBoundSheets = true;
                 }
            } else {
               len = record.serialize( pos + offset, data );
            }
            pos += len;
        }

        LOG.atDebug().log("Exiting serialize workbook");
        return pos;
    }

    /**
     * Perform any work necessary before the workbook is about to be serialized.
     *
     * Include in it ant code that modifies the workbook record stream and affects its size.
     */
    public void preSerialize() {
        // Ensure we have enough tab IDs
        // Can be a few short if new sheets were added
        if (records.getTabpos() > 0) {
            Record rec = records.get(records.getTabpos());
            if (rec instanceof TabIdRecord) {
                TabIdRecord tir = ( TabIdRecord ) rec;
                if(tir.getTabIdSize() < boundsheets.size()) {
                    fixTabIdRecord();
                }
            }
        }
    }

    public int getSize() {
        int retval = 0;

        SSTRecord lSST = null;
        for ( Record record : records.getRecords() ) {
            if (record instanceof SSTRecord) {
                lSST = (SSTRecord)record;
            }

            if (record.getSid() == ExtSSTRecord.sid && lSST != null) {
                retval += lSST.calcExtSSTRecordSize();
            } else {
                retval += record.getRecordSize();
            }
        }

        return retval;
    }

    private static BOFRecord createBOF() {
        BOFRecord retval = new BOFRecord();

        retval.setVersion(( short ) 0x600);
        retval.setType(BOFRecord.TYPE_WORKBOOK);
        retval.setBuild(( short ) 0x10d3);
        retval.setBuildYear(( short ) 1996);
        // was c1 before verify
        retval.setHistoryBitMask(0x41);
        retval.setRequiredVersion(0x6);
        return retval;
    }


    private static MMSRecord createMMS() {
        MMSRecord retval = new MMSRecord();

        retval.setAddMenuCount(( byte ) 0);
        retval.setDelMenuCount(( byte ) 0);
        return retval;
    }

    /**
     * creates the WriteAccess record containing the logged in user's name
     */
    private static WriteAccessRecord createWriteAccess() {
        WriteAccessRecord retval = new WriteAccessRecord();

        String defaultUserName = "POI";
        try {
            String username = System.getProperty("user.name");
            // Google App engine returns null for user.name, see Bug 53974
            if(username == null) {
                username = defaultUserName;
            }

            retval.setUsername(username);
        } catch (AccessControlException e) {
            LOG.atWarn().withThrowable(e).log("can't determine user.name");
            // AccessControlException can occur in a restricted context
            // (client applet/jws application or restricted security server)
            retval.setUsername(defaultUserName);
        }
        return retval;
    }

    private static CodepageRecord createCodepage() {
        CodepageRecord retval = new CodepageRecord();

        retval.setCodepage(CODEPAGE);
        return retval;
    }

    private static DSFRecord createDSF() {
        return new DSFRecord(false); // we don't even support double stream files
    }

    /**
     * creates the TabId record containing an array
     */
    private static TabIdRecord createTabId() {
        return new TabIdRecord();
    }

    /**
     * creates the FnGroupCount record containing the Magic number constant of 14.
     */
    private static FnGroupCountRecord createFnGroupCount() {
        FnGroupCountRecord retval = new FnGroupCountRecord();

        retval.setCount(( short ) 14);
        return retval;
    }

    /**
     * @return a new WindowProtect record with protect set to false.
     */
    private static WindowProtectRecord createWindowProtect() {
        // by default even when we support it we won't
        // want it to be protected
        return new WindowProtectRecord(false);
    }

    /**
     * @return a new Protect record with protect set to false.
     */
    private static ProtectRecord createProtect() {
        // by default even when we support it we won't
        // want it to be protected
        return new ProtectRecord(false);
    }

    /**
     * @return a new Password record with password set to 0x0000 (no password).
     */
    private static PasswordRecord createPassword() {
        return new PasswordRecord(0x0000); // no password by default!
    }

    /**
     * @return a new ProtectionRev4 record with protect set to false.
     */
    private static ProtectionRev4Record createProtectionRev4() {
        return new ProtectionRev4Record(false);
    }

    /**
     * @return a new PasswordRev4 record with password set to 0.
     */
    private static PasswordRev4Record createPasswordRev4() {
        return new PasswordRev4Record(0x0000);
    }

    /**
     * creates the WindowOne record with the following magic values: <P>
     * horizontal hold - 0x168 <P>
     * vertical hold   - 0x10e <P>
     * width           - 0x3a5c <P>
     * height          - 0x23be <P>
     * options         - 0x38 <P>
     * selected tab    - 0 <P>
     * displayed tab   - 0 <P>
     * num selected tab- 0 <P>
     * tab width ratio - 0x258 <P>
     */
    private static WindowOneRecord createWindowOne() {
        WindowOneRecord retval = new WindowOneRecord();

        retval.setHorizontalHold(( short ) 0x168);
        retval.setVerticalHold(( short ) 0x10e);
        retval.setWidth(( short ) 0x3a5c);
        retval.setHeight(( short ) 0x23be);
        retval.setOptions(( short ) 0x38);
        retval.setActiveSheetIndex( 0x0);
        retval.setFirstVisibleTab(0x0);
        retval.setNumSelectedTabs(( short ) 1);
        retval.setTabWidthRatio(( short ) 0x258);
        return retval;
    }

    /**
     * creates the Backup record with backup set to 0. (loose the data, who cares)
     */
    private static BackupRecord createBackup() {
        BackupRecord retval = new BackupRecord();

        retval.setBackup(( short ) 0);   // by default DONT save backups of files...just loose data
        return retval;
    }

    /**
     * creates the HideObj record with hide object set to 0. (don't hide)
     */
    private static HideObjRecord createHideObj() {
        HideObjRecord retval = new HideObjRecord();
        retval.setHideObj(( short ) 0);   // by default set hide object off
        return retval;
    }

    /**
     * creates the DateWindow1904 record with windowing set to 0. (don't window)
     */
    private static DateWindow1904Record createDateWindow1904() {
        DateWindow1904Record retval = new DateWindow1904Record();

        retval.setWindowing(( short ) 0);   // don't EVER use 1904 date windowing...tick tock..
        return retval;
    }

    /**
     * creates the Precision record with precision set to true. (full precision)
     */
    private static PrecisionRecord createPrecision() {
        PrecisionRecord retval = new PrecisionRecord();
        retval.setFullPrecision(true);   // always use real numbers in calculations!
        return retval;
    }

    /**
     * @return a new RefreshAll record with refreshAll set to false. (do not refresh all calcs)
     */
    private static RefreshAllRecord createRefreshAll() {
        return new RefreshAllRecord(false);
    }

    /**
     * creates the BookBool record with saveLinkValues set to 0. (don't save link values)
     */
    private static BookBoolRecord createBookBool() {
        BookBoolRecord retval = new BookBoolRecord();
        retval.setSaveLinkValues(( short ) 0);
        return retval;
    }

    /**
     * creates a Font record with the following magic values: <P>
     * fontheight           = 0xc8<P>
     * attributes           = 0x0<P>
     * color palette index  = 0x7fff<P>
     * bold weight          = 0x190<P>
     * Font Name Length     = 5 <P>
     * Font Name            = Arial <P>
     */
    private static FontRecord createFont() {
        FontRecord retval = new FontRecord();

        retval.setFontHeight(( short ) 0xc8);
        retval.setAttributes(( short ) 0x0);
        retval.setColorPaletteIndex(( short ) 0x7fff);
        retval.setBoldWeight(( short ) 0x190);
        retval.setFontName("Arial");
        return retval;
    }

    /**
     * Creates a FormatRecord object
     * @param id    the number of the format record to create (meaning its position in
     *        a file as M$ Excel would create it.)
     */
    private static FormatRecord createFormat(int id) {
        // we'll need multiple editions for the different formats
        final int[] mappings = {5, 6, 7, 8, 0x2a, 0x29, 0x2c, 0x2b};
        if (id < 0 || id >= mappings.length) {
            throw new  IllegalArgumentException("Unexpected id " + id);
        }
        return new FormatRecord(mappings[id], BuiltinFormats.getBuiltinFormat(mappings[id]));
    }

    /**
     * Creates an ExtendedFormatRecord object
     * @param id    the number of the extended format record to create (meaning its position in
     *        a file as MS Excel would create it.)
     */
    private static ExtendedFormatRecord createExtendedFormat(int id) {
        // we'll need multiple editions
        switch (id) {
            case  0: return createExtendedFormat(0,    0, 0xfffffff5,          0);
            case  1:
            case  2: return createExtendedFormat(1,    0, 0xfffffff5, 0xfffff400);
            case  3:
            case  4: return createExtendedFormat(2,    0, 0xfffffff5, 0xfffff400);
            case  5:
            case  6:
            case  7:
            case  8:
            case  9:
            case 10:
            case 11:
            case 12:
            case 13:
            case 14: return createExtendedFormat(0,    0, 0xfffffff5, 0xfffff400);
            // cell records
            case 15: return createExtendedFormat(0,    0,          1,          0);
            // style
            case 16: return createExtendedFormat(1, 0x2b, 0xfffffff5, 0xfffff800);
            case 17: return createExtendedFormat(1, 0x29, 0xfffffff5, 0xfffff800);
            case 18: return createExtendedFormat(1, 0x2c, 0xfffffff5, 0xfffff800);
            case 19: return createExtendedFormat(1, 0x2a, 0xfffffff5, 0xfffff800);
            case 20: return createExtendedFormat(1, 0x09, 0xfffffff5, 0xfffff800);
            // unused from this point down
            case 21: return createExtendedFormat(5,    0,          1,      0x800);
            case 22: return createExtendedFormat(6,    0,          1,     0x5c00);
            case 23: return createExtendedFormat(0, 0x31,          1,     0x5c00);
            case 24: return createExtendedFormat(0,    8,          1,     0x5c00);
            case 25: return createExtendedFormat(6,    8,          1,     0x5c00);

            default: throw new IllegalStateException("Unrecognized format id: " + id);
        }
    }

    private static ExtendedFormatRecord createExtendedFormat(
        int fontIndex, int formatIndex, int cellOptions, int indentionOptions
    ) {
        ExtendedFormatRecord retval = new ExtendedFormatRecord();
        retval.setFontIndex(( short ) fontIndex);
        retval.setFormatIndex(( short ) formatIndex);
        retval.setCellOptions(( short ) cellOptions);
        retval.setAlignmentOptions(( short ) 0x20);
        retval.setIndentionOptions(( short ) indentionOptions);
        retval.setBorderOptions(( short ) 0);
        retval.setPaletteOptions(( short ) 0);
        retval.setAdtlPaletteOptions(( short ) 0);
        retval.setFillPaletteOptions(( short ) 0x20c0);
        return retval;
    }

    /**
     * creates an default cell type ExtendedFormatRecord object.
     * @return ExtendedFormatRecord with initial defaults (cell-type)
     */
    private static ExtendedFormatRecord createExtendedFormat() {
        ExtendedFormatRecord retval = new ExtendedFormatRecord();

        retval.setFontIndex(( short ) 0);
        retval.setFormatIndex(( short ) 0x0);
        retval.setCellOptions(( short ) 0x1);
        retval.setAlignmentOptions(( short ) 0x20);
        retval.setIndentionOptions(( short ) 0);
        retval.setBorderOptions(( short ) 0);
        retval.setPaletteOptions(( short ) 0);
        retval.setAdtlPaletteOptions(( short ) 0);
        retval.setFillPaletteOptions(( short ) 0x20c0);
        retval.setTopBorderPaletteIdx(HSSFColorPredefined.BLACK.getIndex());
        retval.setBottomBorderPaletteIdx(HSSFColorPredefined.BLACK.getIndex());
        retval.setLeftBorderPaletteIdx(HSSFColorPredefined.BLACK.getIndex());
        retval.setRightBorderPaletteIdx(HSSFColorPredefined.BLACK.getIndex());
        return retval;
    }

    /**
     * Creates a StyleRecord object
     * @param id        the number of the style record to create (meaning its position in
     *                  a file as MS Excel would create it.
     */
    private static StyleRecord createStyle(int id) {
        // we'll need multiple editions
        final int[][] mappings = {
                {0x010, 3}, {0x011, 6}, {0x012, 4}, {0x013, 7}, {0x000, 0}, {0x014, 5}
        };
        if (id < 0 || id >= mappings.length) {
            throw new  IllegalArgumentException("Unexpected style id " + id);
        }

        StyleRecord retval = new StyleRecord();
        retval.setOutlineStyleLevel(( byte ) 0xffffffff);
        retval.setXFIndex(mappings[id][0]);
        retval.setBuiltinStyle(mappings[id][1]);
        return retval;
    }

    /**
     * Creates a palette record initialized to the default palette
     */
    private static PaletteRecord createPalette() {
        return new PaletteRecord();
    }

    /**
     * @return a new UseSelFS object with the use natural language flag set to 0 (false)
     */
    private static UseSelFSRecord createUseSelFS() {
        return new UseSelFSRecord(false);
    }

    /**
     * create a "bound sheet" or "bundlesheet" (depending who you ask) record
     * Always sets the sheet's bof to 0.  You'll need to set that yourself.
     * @param id either sheet 0,1 or 2.
     * @return record containing a BoundSheetRecord
     * @see BoundSheetRecord
     * @see Record
     */
    private static BoundSheetRecord createBoundSheet(int id) {
        return new BoundSheetRecord("Sheet" + (id+1));
    }

    /**
     * Creates the Country record with the default country set to 1
     * and current country set to 7 in case of russian locale ("ru_RU") and 1 otherwise
     */
    private static CountryRecord createCountry() {
        CountryRecord retval = new CountryRecord();

        retval.setDefaultCountry(( short ) 1);

        // from Russia with love ;)
        if ( "ru_RU".equals( LocaleUtil.getUserLocale().toString() ) ) {
            retval.setCurrentCountry(( short ) 7);
        } else {
            retval.setCurrentCountry(( short ) 1);
        }

        return retval;
    }

    /**
     * Creates the ExtendedSST record with numstrings per bucket set to 0x8.  HSSF
     * doesn't yet know what to do with this thing, but we create it with nothing in
     * it hardly just to make Excel happy and our sheets look like Excel's
     */
    private static ExtSSTRecord createExtendedSST() {
        ExtSSTRecord retval = new ExtSSTRecord();
        retval.setNumStringsPerBucket(( short ) 0x8);
        return retval;
    }

    /**
     * lazy initialization
     * Note - creating the link table causes creation of 1 EXTERNALBOOK and 1 EXTERNALSHEET record
     */
    private LinkTable getOrCreateLinkTable() {
        if(linkTable == null) {
            linkTable = new LinkTable((short) getNumSheets(), records);
        }
        return linkTable;
    }

    public int linkExternalWorkbook(String name, Workbook externalWorkbook) {
        return getOrCreateLinkTable().linkExternalWorkbook(name, externalWorkbook);
    }

    /**
     * Finds the first sheet name by his extern sheet index
     * @param externSheetIndex extern sheet index
     * @return first sheet name.
     */
    public String findSheetFirstNameFromExternSheet(int externSheetIndex){
        int indexToSheet = linkTable.getFirstInternalSheetIndexForExtIndex(externSheetIndex);
        return findSheetNameFromIndex(indexToSheet);
    }
    public String findSheetLastNameFromExternSheet(int externSheetIndex){
        int indexToSheet = linkTable.getLastInternalSheetIndexForExtIndex(externSheetIndex);
        return findSheetNameFromIndex(indexToSheet);
    }
    private String findSheetNameFromIndex(int internalSheetIndex) {
        if (internalSheetIndex < 0) {
            // TODO - what does '-1' mean here?
            //error check, bail out gracefully!
            return "";
        }
        if (internalSheetIndex >= boundsheets.size()) {
            // Not sure if this can ever happen (See bug 45798)
            return ""; // Seems to be what excel would do in this case
        }
        return getSheetName(internalSheetIndex);
    }

    public ExternalSheet getExternalSheet(int externSheetIndex) {
        String[] extNames = linkTable.getExternalBookAndSheetName(externSheetIndex);
        if (extNames == null) {
            return null;
        }
        if (extNames.length == 2) {
            return new ExternalSheet(extNames[0], extNames[1]);
        } else {
            return new ExternalSheetRange(extNames[0], extNames[1], extNames[2]);
        }
    }
    public ExternalName getExternalName(int externSheetIndex, int externNameIndex) {
       String nameName = linkTable.resolveNameXText(externSheetIndex, externNameIndex, this);
       if(nameName == null) {
          return null;
       }
       int ix = linkTable.resolveNameXIx(externSheetIndex, externNameIndex);
       return new ExternalName(nameName, externNameIndex, ix);
    }

    /**
     * Finds the (first) sheet index for a particular external sheet number.
     * @param externSheetNumber     The external sheet number to convert
     * @return  The index to the sheet found.
     */
    public int getFirstSheetIndexFromExternSheetIndex(int externSheetNumber)
    {
        return linkTable.getFirstInternalSheetIndexForExtIndex(externSheetNumber);
    }

    /**
     * Finds the last sheet index for a particular external sheet number,
     *  which may be the same as the first (except for multi-sheet references)
     * @param externSheetNumber     The external sheet number to convert
     * @return  The index to the sheet found.
     */
    public int getLastSheetIndexFromExternSheetIndex(int externSheetNumber)
    {
        return linkTable.getLastInternalSheetIndexForExtIndex(externSheetNumber);
    }

    /**
     * Returns the extern sheet number for specific sheet number.
     * If this sheet doesn't exist in extern sheet, add it
     * @param sheetNumber local sheet number
     * @return index to extern sheet
     */
    public short checkExternSheet(int sheetNumber){
        return (short)getOrCreateLinkTable().checkExternSheet(sheetNumber);
    }
    /**
     * Returns the extern sheet number for specific range of sheets.
     * If this sheet range doesn't exist in extern sheet, add it
     * @param firstSheetNumber first local sheet number
     * @param lastSheetNumber last local sheet number
     * @return index to extern sheet
     */
    public short checkExternSheet(int firstSheetNumber, int lastSheetNumber){
        return (short)getOrCreateLinkTable().checkExternSheet(firstSheetNumber, lastSheetNumber);
    }

    public int getExternalSheetIndex(String workbookName, String sheetName) {
        return getOrCreateLinkTable().getExternalSheetIndex(workbookName, sheetName, sheetName);
    }
    public int getExternalSheetIndex(String workbookName, String firstSheetName, String lastSheetName) {
        return getOrCreateLinkTable().getExternalSheetIndex(workbookName, firstSheetName, lastSheetName);
    }


    /** gets the total number of names
     * @return number of names
     */
    public int getNumNames(){
        if(linkTable == null) {
            return 0;
        }
        return linkTable.getNumNames();
    }

    /**
     * gets the name record
     * @param index name index
     * @return name record
     */
    public NameRecord getNameRecord(int index){
        return linkTable.getNameRecord(index);
    }

    /**
     * gets the name comment record
     * @param nameRecord name record who's comment is required.
     * @return name comment record or <code>null</code> if there isn't one for the given name.
     */
    public NameCommentRecord getNameCommentRecord(final NameRecord nameRecord){
        return commentRecords.get(nameRecord.getNameText());
    }

    /**
     * creates new name
     * @return new name record
     */
    public NameRecord createName(){
        return addName(new NameRecord());
    }


    /**
     * adds a name record
     *
     * @param name the name record to be added
     * @return the given name record
     */
    public NameRecord addName(NameRecord name) {
        getOrCreateLinkTable().addName(name);
        return name;
    }

    /**
     * Generates a NameRecord to represent a built-in region
     *
     * @param builtInName the built-in name
     * @param sheetNumber the sheet number
     *
     * @return a new NameRecord
     */
    public NameRecord createBuiltInName(byte builtInName, int sheetNumber) {
        if (sheetNumber < 0 || sheetNumber+1 > Short.MAX_VALUE) {
            throw new IllegalArgumentException("Sheet number ["+sheetNumber+"]is not valid ");
        }

        NameRecord name = new NameRecord(builtInName, sheetNumber);

        if(linkTable.nameAlreadyExists(name)) {
            throw new IllegalStateException("Builtin (" + builtInName
                    + ") already exists for sheet (" + sheetNumber + ")");
        }
        addName(name);
        return name;
    }


    /** removes the name
     * @param nameIndex name index
     */
    public void removeName(int nameIndex){

        if (linkTable.getNumNames() > nameIndex) {
            int idx = findFirstRecordLocBySid(NameRecord.sid);
            records.remove(idx + nameIndex);
            linkTable.removeName(nameIndex);
        }
    }

    /**
     * If a {@link NameCommentRecord} is added or the name it references
     *  is renamed, then this will update the lookup cache for it.
     *
     * @param commentRecord the comment record
     */
    public void updateNameCommentRecordCache(final NameCommentRecord commentRecord) {
       if(commentRecords.containsValue(commentRecord)) {
          for(Entry<String,NameCommentRecord> entry : commentRecords.entrySet()) {
             if(entry.getValue().equals(commentRecord)) {
                commentRecords.remove(entry.getKey());
                break;
             }
          }
       }
       commentRecords.put(commentRecord.getNameText(), commentRecord);
    }

    /**
     * Returns a format index that matches the passed in format.  It does not tie into HSSFDataFormat.
     * @param format the format string
     * @param createIfNotFound creates a new format if format not found
     * @return the format id of a format that matches or -1 if none found and createIfNotFound
     */
    public short getFormat(String format, boolean createIfNotFound) {
      for (FormatRecord r : formats) {
        if (r.getFormatString().equals(format)) {
        return (short)r.getIndexCode();
        }
      }

      if (createIfNotFound) {
        return (short)createFormat(format);
      }

      return -1;
    }

    /**
     * Returns the list of FormatRecords in the workbook.
     * @return ArrayList of FormatRecords in the notebook
     */
    public List<FormatRecord> getFormats() {
      return formats;
    }

    /**
     * Creates a FormatRecord, inserts it, and returns the index code.
     * @param formatString the format string
     * @return the index code of the format record.
     * @see FormatRecord
     * @see Record
     */
    public int createFormat(String formatString) {

        maxformatid = maxformatid >= 0xa4 ? maxformatid + 1 : 0xa4; //Starting value from M$ empirical  study.
        FormatRecord rec = new FormatRecord(maxformatid, formatString);

        int pos = 0;
        while ( pos < records.size() && records.get( pos ).getSid() != FormatRecord.sid ) {
            pos++;
        }
        pos += formats.size();
        formats.add( rec );
        records.add( pos, rec );
        return maxformatid;
    }



    /**
     * Returns the first occurance of a record matching a particular sid.
     *
     * @param sid the sid
     *
     * @return the matching record or {@code null} if it wasn't found
     */
    public Record findFirstRecordBySid(short sid) {
        for (Record record : records.getRecords() ) {
            if (record.getSid() == sid) {
                return record;
            }
        }
        return null;
    }

    /**
     * Returns the index of a record matching a particular sid.
     * @param sid   The sid of the record to match
     * @return      The index of -1 if no match made.
     */
    public int findFirstRecordLocBySid(short sid) {
        int index = 0;
        for (Record record : records.getRecords() ) {
            if (record.getSid() == sid) {
                return index;
            }
            index ++;
        }
        return -1;
    }

    /**
     * Returns the next occurance of a record matching a particular sid.
     *
     * @param sid the sid
     * @param pos specifies the n-th matching sid
     *
     * @return the matching record or {@code null} if it wasn't found
     */
    public Record findNextRecordBySid(short sid, int pos) {
        int matches = 0;
        for (Record record : records.getRecords() ) {
            if (record.getSid() == sid && matches++ == pos) {
                return record;
            }
        }
        return null;
    }

    public List<HyperlinkRecord> getHyperlinks()
    {
        return hyperlinks;
    }

    public List<Record> getRecords() {
        return records.getRecords();
    }

    /**
    * Whether date windowing is based on 1/2/1904 or 1/1/1900.
    * Some versions of Excel (Mac) can save workbooks using 1904 date windowing.
    *
    * @return true if using 1904 date windowing
    */
    public boolean isUsing1904DateWindowing() {
        return uses1904datewindowing;
    }

    /**
     * Returns the custom palette in use for this workbook; if a custom palette record
     * does not exist, then it is created.
     *
     * @return the custom palette
     */
    public PaletteRecord getCustomPalette() {
        PaletteRecord palette;
        int palettePos = records.getPalettepos();
        if (palettePos != -1) {
            Record rec = records.get(palettePos);
            if (rec instanceof PaletteRecord) {
                palette = (PaletteRecord) rec;
            } else {
                throw new IllegalStateException("InternalError: Expected PaletteRecord but got a '"+rec+"'");
            }
        } else {
            palette = createPalette();
            //Add the palette record after the bof which is always the first record
            records.add(1, palette);
            records.setPalettepos(1);
        }
        return palette;
    }

    /**
     * Finds the primary drawing group, if one already exists
     *
     * @return the primary drawing group
     */
    public DrawingManager2 findDrawingGroup() {
        if(drawingManager != null) {
           // We already have it!
           return drawingManager;
        }

        // Need to find a DrawingGroupRecord that contains a EscherDggRecord
        for(Record r : records.getRecords() ) {
            if (!(r instanceof DrawingGroupRecord)) {
                continue;
            }
            DrawingGroupRecord dg = (DrawingGroupRecord)r;
            dg.decode();
            drawingManager = findDrawingManager(dg, escherBSERecords);
            if (drawingManager != null) {
                return drawingManager;
            }
        }

        // TODO: we've already scanned the records, why should this work any better now?
        // Look for the DrawingGroup record
        DrawingGroupRecord dg = (DrawingGroupRecord)findFirstRecordBySid(DrawingGroupRecord.sid);
        drawingManager = findDrawingManager(dg, escherBSERecords);
        return drawingManager;
    }

    private static DrawingManager2 findDrawingManager(DrawingGroupRecord dg, List<EscherBSERecord> escherBSERecords) {
        if (dg == null) {
            return null;
        }
        // If there is one, does it have a EscherDggRecord?
        EscherContainerRecord cr = dg.getEscherContainer();
        if (cr == null) {
            return null;
        }

        EscherDggRecord dgg = null;
        EscherContainerRecord bStore = null;
        for(EscherRecord er : cr) {
            if (er instanceof EscherDggRecord) {
                dgg = (EscherDggRecord) er;
            } else if (er.getRecordId() == EscherContainerRecord.BSTORE_CONTAINER) {
                bStore = (EscherContainerRecord) er;
            }
        }

        if(dgg == null) {
            return null;
        }

        DrawingManager2 dm = new DrawingManager2(dgg);
        if(bStore != null){
            for (EscherRecord bs : bStore) {
                if(bs instanceof EscherBSERecord) {
                    escherBSERecords.add((EscherBSERecord)bs);
                }
            }
        }
        return dm;
    }

    /**
     * Creates a primary drawing group record.  If it already
     *  exists then it's modified.
     */
    public void createDrawingGroup() {
        if (drawingManager == null) {
            EscherContainerRecord dggContainer = new EscherContainerRecord();
            EscherDggRecord dgg = new EscherDggRecord();
            EscherOptRecord opt = new EscherOptRecord();
            EscherSplitMenuColorsRecord splitMenuColors = new EscherSplitMenuColorsRecord();

            dggContainer.setRecordId((short) 0xF000);
            dggContainer.setOptions((short) 0x000F);
            dgg.setRecordId(EscherDggRecord.RECORD_ID);
            dgg.setOptions((short)0x0000);
            dgg.setShapeIdMax(1024);
            dgg.setNumShapesSaved(0);
            dgg.setDrawingsSaved(0);
            dgg.setFileIdClusters(new EscherDggRecord.FileIdCluster[] {} );
            drawingManager = new DrawingManager2(dgg);
            EscherContainerRecord bstoreContainer = null;
            if (!escherBSERecords.isEmpty())
            {
                bstoreContainer = new EscherContainerRecord();
                bstoreContainer.setRecordId( EscherContainerRecord.BSTORE_CONTAINER );
                bstoreContainer.setOptions( (short) ( (escherBSERecords.size() << 4) | 0xF ) );
                for (EscherRecord escherRecord : escherBSERecords) {
                    bstoreContainer.addChildRecord( escherRecord );
                }
            }
            opt.setRecordId((short) 0xF00B);
            opt.setOptions((short) 0x0033);
            opt.addEscherProperty( new EscherBoolProperty(EscherPropertyTypes.TEXT__SIZE_TEXT_TO_FIT_SHAPE, 524296) );
            opt.addEscherProperty( new EscherRGBProperty(EscherPropertyTypes.FILL__FILLCOLOR, 0x08000041) );
            opt.addEscherProperty( new EscherRGBProperty(EscherPropertyTypes.LINESTYLE__COLOR, 134217792) );
            splitMenuColors.setRecordId((short) 0xF11E);
            splitMenuColors.setOptions((short) 0x0040);
            splitMenuColors.setColor1(0x0800000D);
            splitMenuColors.setColor2(0x0800000C);
            splitMenuColors.setColor3(0x08000017);
            splitMenuColors.setColor4(0x100000F7);

            dggContainer.addChildRecord(dgg);
            if (bstoreContainer != null) {
                dggContainer.addChildRecord( bstoreContainer );
            }
            dggContainer.addChildRecord(opt);
            dggContainer.addChildRecord(splitMenuColors);

            int dgLoc = findFirstRecordLocBySid(DrawingGroupRecord.sid);
            if (dgLoc == -1) {
                DrawingGroupRecord drawingGroup = new DrawingGroupRecord();
                drawingGroup.addEscherRecord(dggContainer);
                int loc = findFirstRecordLocBySid(CountryRecord.sid);

                getRecords().add(loc+1, drawingGroup);
            } else {
                DrawingGroupRecord drawingGroup = new DrawingGroupRecord();
                drawingGroup.addEscherRecord(dggContainer);
                getRecords().set(dgLoc, drawingGroup);
            }

        }
    }

    public WindowOneRecord getWindowOne() {
        return windowOne;
    }

    public EscherBSERecord getBSERecord(int pictureIndex) {
        return escherBSERecords.get(pictureIndex-1);
    }

    public int addBSERecord(EscherBSERecord e) {
        createDrawingGroup();

        // maybe we don't need that as an instance variable anymore
        escherBSERecords.add( e );

        int dgLoc = findFirstRecordLocBySid(DrawingGroupRecord.sid);
        DrawingGroupRecord drawingGroup = (DrawingGroupRecord) getRecords().get( dgLoc );

        EscherContainerRecord dggContainer = (EscherContainerRecord) drawingGroup.getEscherRecord( 0 );
        EscherContainerRecord bstoreContainer;
        if (dggContainer.getChild( 1 ).getRecordId() == EscherContainerRecord.BSTORE_CONTAINER )
        {
            bstoreContainer = (EscherContainerRecord) dggContainer.getChild( 1 );
        } else {
            bstoreContainer = new EscherContainerRecord();
            bstoreContainer.setRecordId( EscherContainerRecord.BSTORE_CONTAINER );
            List<EscherRecord> childRecords = dggContainer.getChildRecords();
            childRecords.add(1, bstoreContainer);
            dggContainer.setChildRecords(childRecords);
        }
        bstoreContainer.setOptions( (short) ( (escherBSERecords.size() << 4) | 0xF ) );

        bstoreContainer.addChildRecord( e );

        return escherBSERecords.size();
    }

    public DrawingManager2 getDrawingManager()
    {
        return drawingManager;
    }

    public WriteProtectRecord getWriteProtect() {
        if (writeProtect == null) {
           writeProtect = new WriteProtectRecord();
           int i = findFirstRecordLocBySid(BOFRecord.sid);
           records.add(i+1, writeProtect);
        }
        return this.writeProtect;
    }

    public WriteAccessRecord getWriteAccess() {
        if (writeAccess == null) {
           writeAccess = createWriteAccess();
           int i = findFirstRecordLocBySid(InterfaceEndRecord.sid);
           records.add(i+1, writeAccess);
        }
        return writeAccess;
    }

    public FileSharingRecord getFileSharing() {
        if (fileShare == null) {
           fileShare = new FileSharingRecord();
           int i = findFirstRecordLocBySid(WriteAccessRecord.sid);
           records.add(i+1, fileShare);
        }
        return fileShare;
    }

    /**
     * is the workbook protected with a password (not encrypted)?
     *
     * @return {@code true} if the workbook is write protected
     */
    public boolean isWriteProtected() {
        if (fileShare == null) {
            return false;
        }
        FileSharingRecord frec = getFileSharing();
        return frec.getReadOnly() == 1;
    }

    /**
     * protect a workbook with a password (not encrypted, just sets writeprotect
     * flags and the password.
     *
     * @param password the password
     * @param username the username
     */
    public void writeProtectWorkbook( String password, String username ) {
        FileSharingRecord frec = getFileSharing();
        WriteAccessRecord waccess = getWriteAccess();
        /* WriteProtectRecord wprotect =*/ getWriteProtect();
        frec.setReadOnly((short)1);
        frec.setPassword((short)CryptoFunctions.createXorVerifier1(password));
        frec.setUsername(username);
        waccess.setUsername(username);
    }

    /**
     * removes the write protect flag
     */
    public void unwriteProtectWorkbook() {
        records.remove(fileShare);
        records.remove(writeProtect);
        fileShare = null;
        writeProtect = null;
    }

    /**
     * @param refIndex Index to REF entry in EXTERNSHEET record in the Link Table
     * @param definedNameIndex zero-based to DEFINEDNAME or EXTERNALNAME record
     * @return the string representation of the defined or external name
     */
    public String resolveNameXText(int refIndex, int definedNameIndex) {
        return linkTable.resolveNameXText(refIndex, definedNameIndex, this);
    }

    /**
     *
     * @param name the  name of an external function, typically a name of a UDF
     * @param sheetRefIndex the sheet ref index, or -1 if not known
     * @param udf  locator of user-defined functions to resolve names of VBA and Add-In functions
     * @return the external name or null
     */
    public NameXPtg getNameXPtg(String name, int sheetRefIndex, UDFFinder udf) {
        LinkTable lnk = getOrCreateLinkTable();
        NameXPtg xptg = lnk.getNameXPtg(name, sheetRefIndex);

        if(xptg == null && udf.findFunction(name) != null) {
            // the name was not found in the list of external names
            // check if the Workbook's UDFFinder is aware about it and register the name if it is
            xptg = lnk.addNameXPtg(name);
        }
        return xptg;
    }
    public NameXPtg getNameXPtg(String name, UDFFinder udf) {
        return getNameXPtg(name, -1, udf);
    }

    /**
     * Check if the cloned sheet has drawings. If yes, then allocate a new drawing group ID and
     * re-generate shape IDs
     *
     * @param sheet the cloned sheet
     */
    public void cloneDrawings(InternalSheet sheet){

        findDrawingGroup();

        if(drawingManager == null) {
            //this workbook does not have drawings
            return;
        }

        //check if the cloned sheet has drawings
        int aggLoc = sheet.aggregateDrawingRecords(drawingManager, false);
        if(aggLoc == -1) {
            return;
        }

        EscherAggregate agg = (EscherAggregate) sheet.findFirstRecordBySid(EscherAggregate.sid);
        EscherContainerRecord escherContainer = agg.getEscherContainer();
        if (escherContainer == null) {
            return;
        }

        EscherDggRecord dgg = drawingManager.getDgg();

        //register a new drawing group for the cloned sheet
        int dgId = drawingManager.findNewDrawingGroupId();
        dgg.addCluster( dgId, 0 );
        dgg.setDrawingsSaved(dgg.getDrawingsSaved() + 1);

        EscherDgRecord dg = null;
        for(EscherRecord er : escherContainer) {
            if(er instanceof EscherDgRecord) {
                dg = (EscherDgRecord)er;
                //update id of the drawing in the cloned sheet
                dg.setOptions( (short) ( dgId << 4 ) );
            } else if (er instanceof EscherContainerRecord){
                // iterate over shapes and re-generate shapeId
                for(EscherRecord er2 : (EscherContainerRecord)er) {
                    for(EscherRecord shapeChildRecord : (EscherContainerRecord)er2) {
                        int recordId = shapeChildRecord.getRecordId();
                        if (recordId == EscherSpRecord.RECORD_ID){
                            if (dg == null) {
                                throw new RecordFormatException("EscherDgRecord wasn't set/processed before.");
                            }
                            EscherSpRecord sp = (EscherSpRecord)shapeChildRecord;
                            int shapeId = drawingManager.allocateShapeId(dg);
                            //allocateShapeId increments the number of shapes. roll back to the previous value
                            dg.setNumShapes(dg.getNumShapes()-1);
                            sp.setShapeId(shapeId);
                        } else if (recordId == EscherOptRecord.RECORD_ID){
                            EscherOptRecord opt = (EscherOptRecord)shapeChildRecord;
                            EscherSimpleProperty prop = opt.lookup(
                                    EscherPropertyTypes.BLIP__BLIPTODISPLAY );
                            if (prop != null){
                                int pictureIndex = prop.getPropertyValue();
                                // increment reference count for pictures
                                EscherBSERecord bse = getBSERecord(pictureIndex);
                                bse.setRef(bse.getRef() + 1);
                            }

                        }
                    }
                }
            }
        }
    }

    public NameRecord cloneFilter(int filterDbNameIndex, int newSheetIndex){
        NameRecord origNameRecord = getNameRecord(filterDbNameIndex);
        // copy original formula but adjust 3D refs to the new external sheet index
        int newExtSheetIx = checkExternSheet(newSheetIndex);
        Ptg[] ptgs = origNameRecord.getNameDefinition();
        for (int i=0; i< ptgs.length; i++) {
            Ptg ptg = ptgs[i];

            if (ptg instanceof Area3DPtg) {
                Area3DPtg a3p = (Area3DPtg) ((OperandPtg) ptg).copy();
                a3p.setExternSheetIndex(newExtSheetIx);
                ptgs[i] = a3p;
            } else if (ptg instanceof Ref3DPtg) {
                Ref3DPtg r3p = (Ref3DPtg) ((OperandPtg) ptg).copy();
                r3p.setExternSheetIndex(newExtSheetIx);
                ptgs[i] = r3p;
            }
        }
        NameRecord newNameRecord = createBuiltInName(NameRecord.BUILTIN_FILTER_DB, newSheetIndex+1);
        newNameRecord.setNameDefinition(ptgs);
        newNameRecord.setHidden(true);
        return newNameRecord;

    }
    /**
     * Updates named ranges due to moving of cells
     *
     * @param shifter the formula shifter
     */
    public void updateNamesAfterCellShift(FormulaShifter shifter) {
        for (int i = 0 ; i < getNumNames() ; ++i){
            NameRecord nr = getNameRecord(i);
            Ptg[] ptgs = nr.getNameDefinition();
            if (shifter.adjustFormula(ptgs, nr.getSheetNumber())) {
                nr.setNameDefinition(ptgs);
            }
        }
    }

    /**
     * Get or create RecalcIdRecord
     *
     * @return a new RecalcIdRecord
     *
     * @see HSSFWorkbook#setForceFormulaRecalculation(boolean)
     */
    public RecalcIdRecord getRecalcId(){
        RecalcIdRecord record = (RecalcIdRecord)findFirstRecordBySid(RecalcIdRecord.sid);
        if(record == null){
            record = new RecalcIdRecord();
            // typically goes after the Country record
            int pos = findFirstRecordLocBySid(CountryRecord.sid);
            records.add(pos + 1, record);
        }
        return record;
    }


    /**
     * Changes an external referenced file to another file.
     * A formular in Excel which refers a cell in another file is saved in two parts:
     * The referenced file is stored in an reference table. the row/cell information is saved separate.
     * This method invokation will only change the reference in the lookup-table itself.
     * @param oldUrl The old URL to search for and which is to be replaced
     * @param newUrl The URL replacement
     * @return true if the oldUrl was found and replaced with newUrl. Otherwise false
     */
    public boolean changeExternalReference(String oldUrl, String newUrl) {
        return linkTable.changeExternalReference(oldUrl, newUrl);
    }

    /**
     * Only for internal calls - code based on this is not supported ...
     *
     * @return The list of records.
     */
    @Internal
    public WorkbookRecordList getWorkbookRecordList() {
        return records;
    }
}
