/* ====================================================================
   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.hwpf.model;

import java.io.IOException;

import org.apache.poi.hwpf.model.io.HWPFOutputStream;
import org.apache.poi.util.Internal;

/**
 * Holds information about document notes (footnotes or ending notes)
 * 
 * @author Sergey Vladimirov (vlsergey {at} gmail {doc} com)
 */
@Internal
public class NotesTables
{
    private PlexOfCps descriptors = new PlexOfCps(
            FootnoteReferenceDescriptor.getSize() );

    private final NoteType noteType;

    private PlexOfCps textPositions = new PlexOfCps( 0 );

    public NotesTables( final NoteType noteType )
    {
        this.noteType = noteType;
        textPositions
                .addProperty( new GenericPropertyNode( 0, 1, new byte[0] ) );
    }

    public NotesTables( final NoteType noteType, byte[] tableStream,
            FileInformationBlock fib )
    {
        this.noteType = noteType;
        read( tableStream, fib );
    }

    public GenericPropertyNode getDescriptor( int index )
    {
        return descriptors.getProperty( index );
    }

    public int getDescriptorsCount()
    {
        return descriptors.length();
    }

    public GenericPropertyNode getTextPosition( int index )
    {
        return textPositions.getProperty( index );
    }

    private void read( byte[] tableStream, FileInformationBlock fib )
    {
        int referencesStart = fib.getNotesDescriptorsOffset( noteType );
        int referencesLength = fib.getNotesDescriptorsSize( noteType );

        if ( referencesStart != 0 && referencesLength != 0 )
            this.descriptors = new PlexOfCps( tableStream, referencesStart,
                    referencesLength, FootnoteReferenceDescriptor.getSize() );

        int textPositionsStart = fib.getNotesTextPositionsOffset( noteType );
        int textPositionsLength = fib.getNotesTextPositionsSize( noteType );

        if ( textPositionsStart != 0 && textPositionsLength != 0 )
            this.textPositions = new PlexOfCps( tableStream,
                    textPositionsStart, textPositionsLength, 0 );
    }

    public void writeRef( FileInformationBlock fib, HWPFOutputStream tableStream )
            throws IOException
    {
        if ( descriptors == null || descriptors.length() == 0 )
        {
            fib.setNotesDescriptorsOffset( noteType, tableStream.getOffset() );
            fib.setNotesDescriptorsSize( noteType, 0 );
            return;
        }

        int start = tableStream.getOffset();
        tableStream.write( descriptors.toByteArray() );
        int end = tableStream.getOffset();

        fib.setNotesDescriptorsOffset( noteType, start );
        fib.setNotesDescriptorsSize( noteType, end - start );
    }

    public void writeTxt( FileInformationBlock fib, HWPFOutputStream tableStream )
            throws IOException
    {
        if ( textPositions == null || textPositions.length() == 0 )
        {
            fib.setNotesTextPositionsOffset( noteType, tableStream.getOffset() );
            fib.setNotesTextPositionsSize( noteType, 0 );
            return;
        }

        int start = tableStream.getOffset();
        tableStream.write( textPositions.toByteArray() );
        int end = tableStream.getOffset();

        fib.setNotesTextPositionsOffset( noteType, start );
        fib.setNotesTextPositionsSize( noteType, end - start );
    }
}