/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *
 * $Id: TextualSignature.java,v 1.4 2006/10/31 08:12:45 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.pdf;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import org.apache.log4j.Logger;
import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.util.PDFTextStripper;

import at.gv.egiz.pdfas.exceptions.ErrorCode;
import at.gv.egiz.pdfas.framework.input.PdfDataSource;
import at.gv.egiz.pdfas.performance.PerformanceCounters;
import at.gv.egiz.pdfas.utils.PDFASUtils;
import at.knowcenter.wag.egov.egiz.cfg.ConfigLogger;
import at.knowcenter.wag.egov.egiz.cfg.SettingsReader;
import at.knowcenter.wag.egov.egiz.exceptions.PDFDocumentException;

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Rectangle;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfWriter;

/**
 * Contains helper function for textual signatures.
 * 
 * @author wprinz
 */
public class TextualSignature
{
  /**
  * The logger definition.
  */
  private static final Logger logger_ = ConfigLogger.getLogger(TextualSignature.class);
  
  /**
   * Extracts the document text from a given pdf.
   * 
   * @param pdf_stream
   *          The pdf_input stream.
   * @return Returns the extracted document text.
 * @throws PDFDocumentException 
   * @throws TextExtractionException
   *           Forwarded exception.
   */
  public static String extractTextTextual(PdfDataSource pdfDataSource, String encoding) throws PDFDocumentException 
  {
    PerformanceCounters.textExtractions.increment();
    
    try
    {
      int first_page_rotation = 0;
      // logger_.debug("====================================================");
      // logger_.debug("extractText:");

      // For text extraction, create a temporary object with iText just as the
      // one
      // created
      // when being signed, but of course without adding content.


     // byte[] bytes = normalizePDF(pdf_stream);
    	//iText  
    	
        byte [] pdf_data = pdfDataSource.getAsByteArray();
        PdfReader reader = new PdfReader(pdf_data);
        PDFASUtils.checkReaderPermissions(reader);
        //pdf_stream.close();

        // PERF: PDF normalization needs byte array - this is costy
        ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);

        // For some reason the Reader -> ImportPage -> Writer mechanism produces
        // problems en mass.
        // The text extractor may not be able to extract proper text from
        // documents
        // created with
        // this method (although it works when a Table is appended)... very
        // fragile.

        Document document = new Document();

        PdfWriter writer = PdfWriter.getInstance(document, baos);
        document.open();

        PdfContentByte cb = writer.getDirectContent();
        for (int page_num = 1; page_num <= reader.getNumberOfPages(); page_num++)
        {
          //Rectangle new_size = reader.getPageSize(page_num);
          //logger_.info("PageSize with no rotaion: Pagenr:"+page_num+" Size: "+new_size);
          //document.setPageSize(new_size);
          Rectangle new_size_withrot =reader.getPageSizeWithRotation(page_num);
          if (page_num == 1)
          {
        	//setFirstPageRotation(new_size_withrot.getRotation());
        	first_page_rotation = new_size_withrot.getRotation();
        	//logger_.info("iText first_page_rotation="+new_size_withrot.getRotation());
          }
          //logger_.info("iText set PageSize of page:"+page_num+" to: "+new_size_withrot); 
          //document.setPageSize(new_size);
          document.setPageSize(new_size_withrot);
          document.newPage();

          PdfImportedPage page = writer.getImportedPage(reader, page_num);
          // note that this will add an xobject form to the doc.
          // the xobject form contains the content of the page.
          cb.addTemplate(page, 0, 0);

          // wprinz: debugging
          // cb.beginText();
          // cb.setFontAndSize(BaseFont.createFont(BaseFont.HELVETICA,
          // BaseFont.CP1252, BaseFont.NOT_EMBEDDED), 14);
          // cb.showText("page " + page_num);
          // cb.endText();
          // wprinz: end debugging
        }

        document.close();

        // for (int i = 1; i <= reader.getNumberOfPages(); i++)
        // {
        // Rectangle rect = reader.getBoxSize(i, "bleed");
        // logger_.debug("rect[" + i + "] = " + rect);
        // }

        baos.close();
        byte[] normalizedPDF = baos.toByteArray();

      ByteArrayInputStream bais = new ByteArrayInputStream(normalizedPDF);
      //PDFBox-parser
      PDFParser parser = new PDFParser(bais);
      File temporary_dir = SettingsReader.getTemporaryDirectory();
      //logger_.info("temporary_dir="+temporary_dir.getAbsolutePath());
      parser.setTempDirectory(temporary_dir);
      parser.parse();
      
      PDDocument doc = parser.getPDDocument();
      //System.out.println("pdfBox.getNumberOfPages()"+doc.getNumberOfPages());
      
      PDFTextStripper stripper = new PDFTextStripper();
      stripper.setSortByPosition(false);
      stripper.setGetFirstPageRotationFromThis(true);
      stripper.setFirstPageRotation(first_page_rotation);
      
      // stripper.setStartPage(4);
      // stripper.setEndPage(4);
      logger_.debug("TextualSignator extractTextTextual: Begin stripping text");
      String text;
      try {
    	  text = stripper.getText(doc, encoding);
      } catch (Exception e) {
    	  throw new PDFDocumentException(ErrorCode.TEXT_EXTRACTION_EXCEPTION, "Unable to extract textual content.", e);
      }
      logger_.debug("TextualSignator extractTextTextual: Stripping text ended");
      
      doc.close();
      //logger_.debug("TextualSignator extractTextTextual="+text);
      return text;

    }
    catch (IllegalArgumentException e)
    {
       throw new PDFDocumentException(ErrorCode.DOCUMENT_CANNOT_BE_READ, e);
    }
    catch (IOException e)
    {
      throw new PDFDocumentException(ErrorCode.DOCUMENT_CANNOT_BE_READ, e);
    }
    catch (DocumentException e)
    {
       throw new PDFDocumentException(ErrorCode.DOCUMENT_CANNOT_BE_READ, e);
    }
  }
  
  /**
   * Normalizes a given binary PDF to a version PDFbox can handle correctly.
   * 
   * <p>
   * PDFbox has serious problems with documents that use incremental updates or
   * XObject forms. Therefor use this to remove incremental updates and create a
   * streamlined document.
   * </p>
   * 
   * <p>
   * Note that this has nothing to do with text normalization. It just unifies
   * the PDF documents that are fed into PDFbox for text extraction and page
   * length determination.
   * </p>
   * 
   * @param input_pdf
   *          The input pdf to be normalized.
   * @return Returns the normalized pdf.
   * @throws IOException
   * @throws DocumentException
 * @throws PDFDocumentException 
   */
  public static byte[] normalizePDF(PdfDataSource pdfDataSource) throws IOException, DocumentException, PDFDocumentException
  {
	  //iText
    byte [] pdf_data = pdfDataSource.getAsByteArray();
    PdfReader reader = new PdfReader(pdf_data);
    PDFASUtils.checkReaderPermissions(reader);
    //input_pdf.close();
    
    // PERF: PDF Normalization needs byte array
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    // For some reason the Reader -> ImportPage -> Writer mechanism produces
    // problems en mass.
    // The text extractor may not be able to extract proper text from
    // documents
    // created with
    // this method (although it works when a Table is appended)... very
    // fragile.

    Document document = new Document();

    PdfWriter writer = PdfWriter.getInstance(document, baos);
    document.open();

    PdfContentByte cb = writer.getDirectContent();
    for (int page_num = 1; page_num <= reader.getNumberOfPages(); page_num++)
    {
      Rectangle new_size_withrot =reader.getPageSizeWithRotation(page_num);
      document.setPageSize(new_size_withrot);
      document.newPage();
      PdfImportedPage page = writer.getImportedPage(reader, page_num);
      // note that this will add an xobject form to the doc.
      // the xobject form contains the content of the page.
      cb.addTemplate(page, 0, 0);

      // wprinz: debugging
      // cb.beginText();
      // cb.setFontAndSize(BaseFont.createFont(BaseFont.HELVETICA,
      // BaseFont.CP1252, BaseFont.NOT_EMBEDDED), 14);
      // cb.showText("page " + page_num);
      // cb.endText();
      // wprinz: end debugging
    }

    document.close();

    // for (int i = 1; i <= reader.getNumberOfPages(); i++)
    // {
    // Rectangle rect = reader.getBoxSize(i, "bleed");
    // logger_.debug("rect[" + i + "] = " + rect);
    // }

    baos.close();
    byte[] normalizedPDF = baos.toByteArray();
    return normalizedPDF;
  }
}