/**
 * <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: Verify.java,v 1.7 2006/10/11 07:39:13 wprinz Exp $
 */
package at.gv.egiz.pdfas.web.servlets;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import at.gv.egiz.pdfas.api.PdfAs;
import at.gv.egiz.pdfas.api.analyze.AnalyzeParameters;
import at.gv.egiz.pdfas.api.analyze.AnalyzeResult;
import at.gv.egiz.pdfas.api.commons.Constants;
import at.gv.egiz.pdfas.api.exceptions.PdfAsException;
import at.gv.egiz.pdfas.api.internal.PdfAsInternal;
import at.gv.egiz.pdfas.api.io.DataSource;
import at.gv.egiz.pdfas.api.verify.VerifyAfterAnalysisParameters;
import at.gv.egiz.pdfas.api.verify.VerifyResult;
import at.gv.egiz.pdfas.api.verify.VerifyResults;
import at.gv.egiz.pdfas.web.FormFields;
import at.gv.egiz.pdfas.web.helper.ApiHelper;
import at.gv.egiz.pdfas.web.helper.LocalRequestHelper;
import at.gv.egiz.pdfas.web.helper.WebSettingsReader;
import at.gv.egiz.pdfas.web.io.ByteArrayPdfDataSource;
import at.gv.egiz.pdfas.web.io.TextDataSource;
import at.gv.egiz.pdfas.web.session.SessionAttributes;
import at.gv.egiz.pdfas.web.session.VerifySessionInformation;
import at.knowcenter.wag.egov.egiz.exceptions.PDFDocumentException;
import at.knowcenter.wag.egov.egiz.exceptions.SettingNotFoundException;

/**
 * This method is the verify servlet for the pdf-as web application. It takes
 * get and post requests fill out jsp templates and give the user feedback about
 * the results of the verify process.
 *
 * @author wlackner
 * @author wprinz
 */
public class VerifyServlet extends HttpServlet
{

  /**
   * SVUID.
   */
  private static final long serialVersionUID = 309198792358636766L;

  /**
   * The log.
   */
  private static Log log = LogFactory.getLog(SignServlet.class);

  protected void dispatch(HttpServletRequest request, HttpServletResponse response, String resource) throws ServletException, IOException
  {
    response.setContentType("text/html"); //$NON-NLS-1$
    response.setCharacterEncoding("UTF-8"); //$NON-NLS-1$

    RequestDispatcher disp = getServletContext().getRequestDispatcher(resource);
    disp.forward(request, response);
  }

  protected void dispatchToResults(VerifyResults verifyResults, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    request.setAttribute("results", verifyResults); //$NON-NLS-1$
    dispatch(request, response, "/jsp/results.jsp"); //$NON-NLS-1$
  }

  /**
   * Processes the verify upload.
   *
   * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest,
   *      javax.servlet.http.HttpServletResponse)
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    // for performance measurement
    long startTime = 0;
    if (log.isInfoEnabled()) {
    	startTime = System.currentTimeMillis();
    }

    try
    {
      UploadedData ud = retrieveUploadedDataFromRequest(request);

      VerifySessionInformation si = new VerifySessionInformation();
      si.connector = ud.sig_app;
      si.application = "verify";
      si.mode = null;
      si.inputDataSource = ud.dataSource;
      si.type = null;
      si.file_name = ud.file_name;

      //afitzek
      si.startTime = startTime;
//      si.user_name = null;
//      si.user_password = null;

      PdfAs pdfAs = ApiHelper.getPdfAsFromContext(getServletContext());
      PdfAsInternal pdfAsInternal = ApiHelper.getPdfAsInternalFromContext(getServletContext());
      AnalyzeParameters analyzeParameters = new AnalyzeParameters();
      analyzeParameters.setDocument(ud.dataSource);
      analyzeParameters.setVerifyMode(Constants.VERIFY_MODE_FULL_CONSERVATIVE);
      AnalyzeResult analyzeResult = pdfAs.analyze(analyzeParameters);
      si.analyzeResult = analyzeResult;

      request.getSession().setAttribute(SessionAttributes.ATTRIBUTE_SESSION_INFORMATION, si);

      if (ud.preview)
      {
        dispatch(request, response, "/jsp/verifylist.jsp");
      }
      else
      {
        if (LocalRequestHelper.isConnectorLocal(si.connector))
        {
          String dispatch_to = LocalRequestHelper.processLocalVerify(pdfAsInternal, si, analyzeResult.getSignatures(), request, response);

          dispatch(request, response, dispatch_to);
          return;
        }

        VerifyAfterAnalysisParameters verifyAfterAnalysisParameters = new VerifyAfterAnalysisParameters();
        verifyAfterAnalysisParameters.setAnalyzeResult(si.analyzeResult);
        verifyAfterAnalysisParameters.setSignatureDevice(si.connector);
        verifyAfterAnalysisParameters.setVerifySignatureIndex(-1);
        VerifyResults verifyResults = pdfAs.verify(verifyAfterAnalysisParameters);
        si.verifyResults = verifyResults;

        dispatchToResults(verifyResults, request, response);

        // for performance measurement
        if (log.isInfoEnabled()) {
        	long endTime = System.currentTimeMillis();
        	String toReport = "VERIFY;"+ ud.file_name + ";"+ 0 + ";" + (endTime - startTime) + ";" + debugVerifyResults(verifyResults);
        	log.info(toReport);
        }

      }

    }
    catch (FileUploadException e)
    {
      request.setAttribute("error", "Fehler beim Upload der Daten");
      request.setAttribute("cause", "Beim Upload der Daten ist ein Fehler aufgetreten.");
      dispatch(request, response, "/jsp/error_verify.jsp");
    }
    catch (PdfAsException e)
    {
      log.error(e.getMessage(), e);
      SignServlet.prepareDispatchToErrorPage(e, request);
      dispatch(request, response, "/jsp/error_verify.jsp");
    }

  }

  protected UploadedData retrieveUploadedDataFromRequest(HttpServletRequest request) throws ServletException, UnsupportedEncodingException, FileUploadException, PDFDocumentException
  {
    DiskFileItemFactory fif = new DiskFileItemFactory();
    fif.setRepository(WebSettingsReader.getTemporaryDirectory());

    ServletFileUpload sfu = new ServletFileUpload(fif);

    List items = sfu.parseRequest(request);

    FileItem upload_fi = null;
    FileItem connector_fi = null;
    // FileItem mode_fi = null;
    FileItem preview_fi = null;

    String characterEncoding = request.getCharacterEncoding();
    log.debug("request character encoding = " + characterEncoding);

    {
      Iterator it = items.iterator();
      while (it.hasNext())
      {
        FileItem item = (FileItem) it.next();
        log.debug("item = " + item.getFieldName()); //$NON-NLS-1$

        if (item.isFormField())
        {
          String item_string = item.getString("UTF-8"); //$NON-NLS-1$
          log.debug("  form field string = " + item_string); //$NON-NLS-1$
        }
        else
        {
          log.debug("  filename = " + item.getName()); //$NON-NLS-1$
          log.debug("  filesize = " + item.getSize()); //$NON-NLS-1$
        }

        if (item.getFieldName().equals(FormFields.FIELD_UPLOAD))
        {
          upload_fi = item;
          continue;
        }

        if (item.getFieldName().equals(FormFields.FIELD_CONNECTOR))
        {
          connector_fi = item;
          continue;
        }

        if (item.getFieldName().equals(FormFields.FIELD_PREVIEW))
        {
          preview_fi = item;
          continue;
        }

        throw new ServletException("unrecognized POST data."); //$NON-NLS-1$
      }
    }

    if (upload_fi == null || connector_fi == null || /* mode_fi == null || */preview_fi == null)
    {
      throw new ServletException("Unsufficient data provided in request."); //$NON-NLS-1$
    }

    String connector = connector_fi.getString("UTF-8"); //$NON-NLS-1$

    String preview_str = preview_fi.getString("UTF-8"); //$NON-NLS-1$
    if (!preview_str.equals(FormFields.VALUE_TRUE) && !preview_str.equals(FormFields.VALUE_FALSE))
    {
      throw new ServletException("The preview '" + preview_str + "' is unrecognized."); //$NON-NLS-1$//$NON-NLS-2$
    }
    boolean preview = false;
    if (preview_str.equals(FormFields.VALUE_TRUE))
    {
      preview = true;
    }

    // process the request
    DataSource dataSource = convertUploadToDataSource(upload_fi);

    UploadedData ud = new UploadedData();
    ud.preview = preview;
    ud.sig_app = connector;
    ud.file_name = upload_fi.getName();
    ud.dataSource = dataSource;
    // ud.file_data = document_bytes;

    return ud;
  }

  protected DataSource convertUploadToDataSource(FileItem upload_fi) throws PDFDocumentException
  {
    log.debug("file content type =" + upload_fi.getContentType()); //$NON-NLS-1$
    log.debug("file size = " + upload_fi.getSize()); //$NON-NLS-1$
    if (upload_fi.getSize() <= 0)
    {
      throw new PDFDocumentException(250, "The document is empty."); //$NON-NLS-1$
    }


    // TR: do not check MIME-type of incoming file - might vary depending on the browser used
    if ((upload_fi.getContentType() != null ) && ((upload_fi.getContentType().startsWith("application/pdf") || upload_fi.getContentType().startsWith("application/x-download") )))
    {
       return new ByteArrayPdfDataSource(upload_fi.get());
    }

    try
    {
//      String fileNameSuffix = TempDirHelper.extractFileNameSuffix(upload_fi.getName());
      String text = new String(upload_fi.get(), "UTF-8"); //$NON-NLS-1$
      TextDataSource textDataSource = new TextDataSource(text);
      return textDataSource;
    }
    catch (IOException e)
    {
      throw new PDFDocumentException(201, e);
    }
  }

  /**
   * Extracts the extension from a file name string.
   *
   * <p>
   * The extension of a file name is whatever text follows the last '.'.
   * </p>
   *
   * @param file_name
   *          The file name.
   * @return Returns the extension. If the file name ends with the '.', then an
   *         empty string is returned. If the file name doesn't contain any '.'
   *         or file_name is null, null is returned.
   */
  public static String extractExtension(String file_name)
  {
    if (file_name == null)
    {
      return null;
    }

    int dot_index = file_name.lastIndexOf('.');
    if (dot_index < 0)
    {
      return null;
    }
    return file_name.substring(dot_index + 1);
  }

  protected static class UploadedData
  {
    protected boolean preview = false;

    protected String sig_app = null;

    protected String file_name = null;

    protected DataSource dataSource = null;
  }

  /**
   * Formats the verification results for debugging. Returns  0 if no error occurs or the sum of all error-codes.
   *
   * @param verifyResults
   *
   * @param writer
   *          The output sink to write the formatted text to.
   * @throws SettingNotFoundException
   *           Forwarded exception.
   */
  public static int debugVerifyResults(VerifyResults verifyResults) throws SettingNotFoundException
  {
	int toreturn = 0;
    Iterator it = verifyResults.getResults().iterator();
    while (it.hasNext())
    {
      VerifyResult result = (VerifyResult) it.next();

      toreturn += result.getValueCheckCode().getCode();
    }
    return toreturn;
  }

  public boolean isPDF(byte[] data) {
	   final byte[] PDF_MAGIC_NUMBER = { (byte) 0x25, (byte) 0x50, (byte)
	0x44, (byte) 0x46 }; // %PDF
	   if (data == null || data.length < PDF_MAGIC_NUMBER.length) {
	     return false;
	   }
	   byte[] documentHeader = new byte[PDF_MAGIC_NUMBER.length];
	   System.arraycopy(data, 0, documentHeader, 0, documentHeader.length);
	   return Arrays.equals(documentHeader, PDF_MAGIC_NUMBER);
	}


}