/**************************************************************************
/* A factory for creating Lucene Documents from pdf-files.
/* 
/* This code is derived from code contained in PDFBox. See the file
/* COPYING.PDFBox in the toplevel-directory of the distribution for
/* copyright information.
/*
/* Copyright (c) 2003-2004 by Bernhard Bablok (mail@bablokb.de)
/*
/* This library is free software; you can redistribute it and/or modify
/* it under the terms of the GNU Lesser General Public License as published
/* by  the Free Software Foundation; either version 2 of the License or
/* (at your option) any later version.
/*
/* This library is distributed in the hope that it will be useful, but
/* WITHOUT ANY WARRANTY; without even the implied warranty of
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
/* GNU Lesser General Public License for more details.
/*
/* You should have received a copy of the GNU Lesser General Public License
/* along with this library; see the file COPYING.LESSER.  If not, write to
/* the Free Software Foundation Inc., 59 Temple Place - Suite 330,
/* Boston, MA  02111-1307 USA
/**************************************************************************/

package de.bablokb.luala.lib;

import java.io.*;
import java.util.*;

import org.apache.lucene.document.*;

import org.pdfbox.pdfparser.*;
import org.pdfbox.pdmodel.*;
import org.pdfbox.encryption.*;
import org.pdfbox.exceptions.*;
import org.pdfbox.util.*;

/**
   A factory for creating Lucene Documents from pdf-files. This
   factory uses code from PDFBox.

    @version $Revision: 1.2 $
    @author  $Author: bablokb $
*/

public class PDFDocumentFactory extends StandardDocumentFactory {

  ////////////////////////////////////////////////////////////////////////////

  /**
    Create a Lucene-Document with the extracted pdf-text as a TEXT-field.

    @param name The name of the source-document

    @return A {@link org.apache.lucene.document.Document}

    @throws FactoryException
  */

  public Document createDocument(String name) throws FactoryException {
    PDDocument pdfDoc = null;
    try {
      Document doc = super.createDocument(name);
      pdfDoc = getPDFDocument(name);
      addFields(doc,pdfDoc);
      Reader reader = getReader(pdfDoc); 
      addSummary(doc,reader);
      addContent(doc,reader);
      if(pdfDoc != null)
	pdfDoc.close();
      return doc;
    } catch (Exception e) {
      try {
	if(pdfDoc != null)
	  pdfDoc.close();
      } catch (Exception e2) {
      }
      throw new FactoryException(e);
    }
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Set the type-field of this document.

     @param doc  The document
  */

  public void setType(Document doc) {
    doc.add(Field.UnIndexed(TYPE,"application/pdf"));
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Create a PDDocument from the source-document.

     @param name The name of the source-document
  */

  private PDDocument getPDFDocument(String name) throws Exception {
    FileInputStream is = new FileInputStream(name);
    PDDocument pdfDocument = null;
    InputStreamReader reader;
    try {
      PDFParser parser = new PDFParser(is);
      parser.parse();
      pdfDocument = parser.getPDDocument();
      if(pdfDocument.isEncrypted()) {
	DecryptDocument decryptor = new DecryptDocument(pdfDocument);
	//Just try using the default password and move on
	decryptor.decryptDocument("");
      }
    } catch (Exception e) {
    }
    return pdfDocument;
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Get a reader for the text-content of the PDF-document.

    @param pdfDoc The PDDocument
  */

  private Reader getReader(PDDocument pdfDoc) throws IOException {
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    OutputStreamWriter writer = new OutputStreamWriter(stream);
    PDFTextStripper stripper = new PDFTextStripper();
    stripper.writeText(pdfDoc.getDocument(),writer);
    writer.close();

    char[] contents = stream.toString().toCharArray();
    stream.close();
    return new CharArrayReader(contents);
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Add additional (PDF-specific) fields to the document.

     @param doc    The Lucene-document
     @param pdfDoc The-PDDocument
  */

  private void addFields(Document doc,PDDocument pdfDoc) throws Exception {
    PDDocumentInformation info = pdfDoc.getDocumentInformation();
    if(info.getAuthor() != null)
	doc.add(Field.Text(AUTHOR,info.getAuthor()));
    if(info.getCreationDate() != null) {
      Date date = info.getCreationDate().getTime();
      if(date.getTime() >= 0)
	doc.add(Field.Text(DATE_CREATED,DateField.dateToString(date)));
    }
    if(info.getCreator() != null)
      doc.add(Field.Text("Creator",info.getCreator()));
    if(info.getKeywords() != null)
      doc.add(Field.Text(KEYWORDS,info.getKeywords()));
    if(info.getModificationDate() != null) {
	Date date = info.getModificationDate().getTime();
	if(date.getTime() >= 0)
	    doc.add(Field.Text(DATE_MOD,DateField.dateToString(date)));
    }
    if(info.getProducer() != null)
      doc.add(Field.Text("Producer",info.getProducer()));
    if(info.getSubject() != null)
      doc.add(Field.Text(SUBJECT,info.getSubject()));
    if(info.getTitle() != null)
      doc.add(Field.Text(TITLE,info.getTitle()));
    if(info.getTrapped() != null)
      doc.add(Field.Text("Trapped",info.getTrapped()));
  }
}