/* ====================================================================
   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.converter;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.io.output.StringBuilderWriter;
import org.apache.logging.log4j.Logger;
import org.apache.poi.logging.PoiLogManager;
import org.apache.poi.hpsf.SummaryInformation;
import org.apache.poi.hwpf.HWPFDocument;
import org.apache.poi.hwpf.HWPFDocumentCore;
import org.apache.poi.hwpf.usermodel.Bookmark;
import org.apache.poi.hwpf.usermodel.CharacterRun;
import org.apache.poi.hwpf.usermodel.OfficeDrawing;
import org.apache.poi.hwpf.usermodel.Paragraph;
import org.apache.poi.hwpf.usermodel.Picture;
import org.apache.poi.hwpf.usermodel.Range;
import org.apache.poi.hwpf.usermodel.Section;
import org.apache.poi.hwpf.usermodel.Table;
import org.apache.poi.hwpf.usermodel.TableCell;
import org.apache.poi.hwpf.usermodel.TableRow;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.Entry;
import org.apache.poi.util.Beta;
import org.apache.poi.util.XMLHelper;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

@Beta
public class WordToTextConverter extends AbstractWordConverter {
    private static final Logger LOG = PoiLogManager.getLogger(WordToTextConverter.class);

    private static final int MAX_NESTED_CHILD_NODES = 300;

    public static String getText( DirectoryNode root ) throws Exception
    {
        final HWPFDocumentCore wordDocument = AbstractWordUtils.loadDoc( root );
        return getText( wordDocument );
    }

    public static String getText( File docFile ) throws Exception
    {
        final HWPFDocumentCore wordDocument = AbstractWordUtils
                .loadDoc( docFile );
        return getText( wordDocument );
    }

    public static String getText( final HWPFDocumentCore wordDocument )
            throws Exception
    {
        WordToTextConverter wordToTextConverter = new WordToTextConverter(
                XMLHelper.newDocumentBuilder().newDocument() );
        wordToTextConverter.processDocument( wordDocument );
        return wordToTextConverter.getText();
    }

    /**
     * Java main() interface to interact with {@link WordToTextConverter}
     *
     * <p>
     * Usage: WordToTextConverter infile outfile
     * </p>
     * Where infile is an input .doc file ( Word 95-2007) which will be rendered
     * as plain text into outfile
     */
    public static void main( String[] args ) throws Exception {
        if ( args.length < 2 )
        {
            System.err.println( "Usage: WordToTextConverter <inputFile.doc> <saveTo.txt>" );
            return;
        }

        System.out.println( "Converting " + args[0] );
        System.out.println( "Saving output to " + args[1] );

        Document doc = WordToTextConverter.process( new File( args[0] ) );

        DOMSource domSource = new DOMSource( doc );
        StreamResult streamResult = new StreamResult( new File( args[1] ) );

        Transformer serializer = XMLHelper.newTransformer();
        // TODO set encoding from a command argument
        serializer.setOutputProperty( OutputKeys.METHOD, "text" );
        serializer.transform( domSource, streamResult );
    }

    private static Document process( File docFile ) throws IOException {
        try (final HWPFDocumentCore wordDocument = AbstractWordUtils.loadDoc( docFile )) {
            WordToTextConverter wordToTextConverter = new WordToTextConverter(
                    XMLHelper.newDocumentBuilder().newDocument());
            wordToTextConverter.processDocument(wordDocument);
            return wordToTextConverter.getDocument();
        }
    }

    private final AtomicInteger noteCounters = new AtomicInteger( 1 );

    private Element notes;

    private boolean outputSummaryInformation;

    private final TextDocumentFacade textDocumentFacade;

    /**
     * Creates new instance of {@link WordToTextConverter}. Can be used for
     * output several {@link HWPFDocument}s into single text document.
     *
     */
    public WordToTextConverter() {
        this.textDocumentFacade = new TextDocumentFacade(
                XMLHelper.newDocumentBuilder().newDocument() );
    }

    /**
     * Creates new instance of {@link WordToTextConverter}. Can be used for
     * output several {@link HWPFDocument}s into single text document.
     *
     * @param document
     *            XML DOM Document used as storage for text pieces
     */
    @SuppressWarnings("WeakerAccess")
    public WordToTextConverter(Document document )
    {
        this.textDocumentFacade = new TextDocumentFacade( document );
    }

    @SuppressWarnings("unused")
    public WordToTextConverter(TextDocumentFacade textDocumentFacade )
    {
        this.textDocumentFacade = textDocumentFacade;
    }

    @Override
    protected void afterProcess()
    {
        if ( notes != null )
            textDocumentFacade.getBody().appendChild( notes );
    }

    public Document getDocument()
    {
        return textDocumentFacade.getDocument();
    }

    public String getText() throws Exception
    {
        StringBuilderWriter stringWriter = new StringBuilderWriter(1024);
        DOMSource domSource = new DOMSource( getDocument() );
        StreamResult streamResult = new StreamResult( stringWriter );

        Transformer serializer =  XMLHelper.newTransformer();
        // TODO set encoding from a command argument
        serializer.setOutputProperty( OutputKeys.METHOD, "text" );
        serializer.transform( domSource, streamResult );

        return stringWriter.toString();
    }

    @SuppressWarnings("WeakerAccess")
    public boolean isOutputSummaryInformation()
    {
        return outputSummaryInformation;
    }

    @Override
    protected void outputCharacters( Element block, CharacterRun characterRun,
            String text )
    {
        block.appendChild( textDocumentFacade.createText( text ) );
    }

    @Override
    protected void processBookmarks( HWPFDocumentCore wordDocument,
            Element currentBlock, Range range, int currentTableLevel,
            List<Bookmark> rangeBookmarks )
    {
        processCharacters( wordDocument, currentTableLevel, range, currentBlock );
    }

    @Override
    protected void processDocumentInformation(
            SummaryInformation summaryInformation )
    {
        if ( isOutputSummaryInformation() )
        {
            if ( AbstractWordUtils.isNotEmpty( summaryInformation.getTitle() ) )
                textDocumentFacade.setTitle( summaryInformation.getTitle() );

            if ( AbstractWordUtils.isNotEmpty( summaryInformation.getAuthor() ) )
                textDocumentFacade.addAuthor( summaryInformation.getAuthor() );

            if ( AbstractWordUtils
                    .isNotEmpty( summaryInformation.getComments() ) )
                textDocumentFacade.addDescription( summaryInformation
                        .getComments() );

            if ( AbstractWordUtils
                    .isNotEmpty( summaryInformation.getKeywords() ) )
                textDocumentFacade.addKeywords( summaryInformation
                        .getKeywords() );
        }
    }

    @Override
    public void processDocumentPart( HWPFDocumentCore wordDocument, Range range )
    {
        super.processDocumentPart( wordDocument, range );
        afterProcess();
    }

    @Override
    protected void processDrawnObject( HWPFDocument doc,
            CharacterRun characterRun, OfficeDrawing officeDrawing,
            String path, Element block )
    {
        // ignore
    }

    @Override
    protected void processEndnoteAutonumbered( HWPFDocument wordDocument,
            int noteIndex, Element block, Range endnoteTextRange )
    {
        processNote( wordDocument, block, endnoteTextRange );
    }

    @Override
    protected void processFootnoteAutonumbered( HWPFDocument wordDocument,
            int noteIndex, Element block, Range footnoteTextRange )
    {
        processNote( wordDocument, block, footnoteTextRange );
    }

    @Override
    protected void processHyperlink( HWPFDocumentCore wordDocument,
            Element currentBlock, Range textRange, int currentTableLevel,
            String hyperlink )
    {
        processCharacters( wordDocument, currentTableLevel, textRange,
                currentBlock );

        currentBlock.appendChild( textDocumentFacade.createText( " ("
                + UNICODECHAR_ZERO_WIDTH_SPACE
                + hyperlink.replace( "/", UNICODECHAR_ZERO_WIDTH_SPACE
                        + "\\/" + UNICODECHAR_ZERO_WIDTH_SPACE )
                + UNICODECHAR_ZERO_WIDTH_SPACE + ")" ) );
    }

    @Override
    protected void processImage( Element currentBlock, boolean inlined,
            Picture picture )
    {
        // ignore
    }

    @Override
    protected void processImage( Element currentBlock, boolean inlined,
            Picture picture, String url )
    {
        // ignore
    }

    @Override
    protected void processImageWithoutPicturesManager( Element currentBlock,
            boolean inlined, Picture picture )
    {
        // ignore
    }

    @Override
    protected void processLineBreak( Element block, CharacterRun characterRun )
    {
        block.appendChild( textDocumentFacade.createText( "\n" ) );
    }

    private void processNote( HWPFDocument wordDocument, Element block, Range noteTextRange ) {
        final int noteIndex = noteCounters.getAndIncrement();
        block.appendChild( textDocumentFacade
                .createText( UNICODECHAR_ZERO_WIDTH_SPACE + "[" + noteIndex
                        + "]" + UNICODECHAR_ZERO_WIDTH_SPACE ) );

        if ( notes == null )
            notes = textDocumentFacade.createBlock();

        Element note = textDocumentFacade.createBlock();
        notes.appendChild( note );

        // avoid StackOverflowException with very deeply nested files (mostly synthetic test files via fuzzing)
        // if this limit is reached in real-word documents, we can make this configurable
        if (note.getParentNode() != null && note.getParentNode().getChildNodes().getLength() > MAX_NESTED_CHILD_NODES) {
            throw new IllegalStateException("Had more than the limit of " + MAX_NESTED_CHILD_NODES + " nested child notes");
        }

        note.appendChild( textDocumentFacade.createText( "^" + noteIndex
                + "\t " ) );
        processCharacters( wordDocument, Integer.MIN_VALUE, noteTextRange, note );
        note.appendChild( textDocumentFacade.createText( "\n" ) );
    }

    @Override
    protected boolean processOle2( HWPFDocument wordDocument, Element block,
            Entry entry ) throws Exception
    {
        if ( !( entry instanceof DirectoryNode ) )
            return false;
        DirectoryNode directoryNode = (DirectoryNode) entry;

        /*
         * even if there is no ExtractorFactory in classpath, still support
         * included Word's objects
         */
        if ( directoryNode.hasEntryCaseInsensitive( "WordDocument" ) )
        {
            String text = WordToTextConverter.getText( (DirectoryNode) entry );
            block.appendChild( textDocumentFacade
                    .createText( UNICODECHAR_ZERO_WIDTH_SPACE + text
                            + UNICODECHAR_ZERO_WIDTH_SPACE ) );
            return true;
        }

        Object extractor;
        try
        {
            Class<?> cls = Class
                    .forName( "org.apache.poi.extractor.ExtractorFactory" );
            Method createExtractor = cls.getMethod( "createExtractor",
                    DirectoryNode.class );
            extractor = createExtractor.invoke( null, directoryNode );
        }
        catch ( Exception exc )
        {
            // no extractor in classpath
            LOG.atWarn().withThrowable(exc).log("There is an OLE object entry '{}', but there is no text " +
                    "extractor for this object type or text extractor factory is not available", entry.getName());
            return false;
        }

        try
        {
            Method getText = extractor.getClass().getMethod( "getText" );
            String text = (String) getText.invoke( extractor );

            block.appendChild( textDocumentFacade
                    .createText( UNICODECHAR_ZERO_WIDTH_SPACE + text
                            + UNICODECHAR_ZERO_WIDTH_SPACE ) );
            return true;
        }
        catch ( Exception exc )
        {
            LOG.atError().withThrowable(exc).log("Unable to extract text from OLE entry '{}'", entry.getName());
            return false;
        }
    }

    @Override
    protected void processPageBreak( HWPFDocumentCore wordDocument, Element flow )
    {
        Element block = textDocumentFacade.createBlock();
        block.appendChild( textDocumentFacade.createText( "\n" ) );
        flow.appendChild( block );
    }

    @Override
    protected void processPageref( HWPFDocumentCore wordDocument,
            Element currentBlock, Range textRange, int currentTableLevel,
            String pageref )
    {
        processCharacters( wordDocument, currentTableLevel, textRange,
                currentBlock );
    }

    @Override
    protected void processParagraph( HWPFDocumentCore wordDocument,
            Element parentElement, int currentTableLevel, Paragraph paragraph,
            String bulletText )
    {
        Element pElement = textDocumentFacade.createParagraph();
        pElement.appendChild( textDocumentFacade.createText( bulletText ) );
        processCharacters( wordDocument, currentTableLevel, paragraph, pElement );
        pElement.appendChild( textDocumentFacade.createText( "\n" ) );
        parentElement.appendChild( pElement );
    }

    @Override
    protected void processSection( HWPFDocumentCore wordDocument,
            Section section, int s )
    {
        Element sectionElement = textDocumentFacade.createBlock();
        processParagraphes( wordDocument, sectionElement, section,
                Integer.MIN_VALUE );
        sectionElement.appendChild( textDocumentFacade.createText( "\n" ) );
        textDocumentFacade.body.appendChild( sectionElement );
    }

    protected void processTable( HWPFDocumentCore wordDocument, Element flow,
            Table table )
    {
        final int tableRows = table.numRows();
        for ( int r = 0; r < tableRows; r++ )
        {
            TableRow tableRow = table.getRow( r );

            Element tableRowElement = textDocumentFacade.createTableRow();

            final int rowCells = tableRow.numCells();
            for ( int c = 0; c < rowCells; c++ )
            {
                TableCell tableCell = tableRow.getCell( c );

                Element tableCellElement = textDocumentFacade.createTableCell();

                if ( c != 0 )
                    tableCellElement.appendChild( textDocumentFacade
                            .createText( "\t" ) );

                processCharacters( wordDocument, table.getTableLevel(),
                        tableCell, tableCellElement );
                tableRowElement.appendChild( tableCellElement );
            }

            tableRowElement.appendChild( textDocumentFacade.createText( "\n" ) );
            flow.appendChild( tableRowElement );
        }
    }

    @SuppressWarnings("unused")
    public void setOutputSummaryInformation(boolean outputDocumentInformation )
    {
        this.outputSummaryInformation = outputDocumentInformation;
    }

}
