/*
 * <copyright> Copyright (c) 2006 by Know-Center, Graz, Austria </copyright>
 * 
 * This software is the confidential and proprietary information of Know-Center,
 * Graz, Austria. You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Know-Center.
 * 
 * KNOW-CENTER MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
 * NON-INFRINGEMENT. KNOW-CENTER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES.
 * 
 * $Id: Verify.java,v 1.7 2006/10/11 07:39:13 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.web;

import java.io.IOException;
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.log4j.Logger;

import at.knowcenter.wag.egov.egiz.PdfAS;
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 at.knowcenter.wag.egov.egiz.exceptions.PresentableException;
import at.knowcenter.wag.egov.egiz.framework.VerificationFilter;
import at.knowcenter.wag.egov.egiz.sig.ConnectorFactory;

/**
 * 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 Verify extends HttpServlet
{

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

  /**
   * The logger.
   */
  private static final Logger logger_ = ConfigLogger.getLogger(Verify.class);

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

    RequestDispatcher disp = getServletContext().getRequestDispatcher(resource);
    disp.forward(request, response);
  }
  
  protected void dispatchToResults(List results, HttpServletRequest request,
      HttpServletResponse response) throws ServletException, IOException
  {
    request.setAttribute("results", results);
    dispatch(request, response, "/jsp/results.jsp");
  }


  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    dispatch(request, response, "/jsp/verifyupload.jsp");
  }

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {

    DiskFileItemFactory fif = new DiskFileItemFactory();
    fif.setRepository(SettingsReader.getTemporaryDirectory());
    ServletFileUpload sfu = new ServletFileUpload(fif);

    try
    {

      List items = sfu.parseRequest(request);

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

      {
        Iterator it = items.iterator();
        while (it.hasNext())
        {
          FileItem item = (FileItem) it.next();
          logger_.debug("item = " + item.getFieldName());

          if (item.isFormField())
          {
            byte[] item_data = item.get();
            String item_string = new String(item_data, "UTF-8");
            logger_.debug("  form field string = " + item_string);
          }
          else
          {
            logger_.debug("  filename = " + item.getName());
            logger_.debug("  filesize = " + item.getSize());
          }

          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_MODE))
//          {
//            mode_fi = item;
//            continue;
//          }

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

          throw new ServletException("unrecognized POST data.");
        }
      }

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

      String connector = connector_fi.getString("UTF-8");

//      String mode = mode_fi.getString("UTF-8");
//      if (!mode.equals(FormFields.VALUE_MODE_BINARY) && !mode.equals(FormFields.VALUE_MODE_TEXTUAL))
//      {
//        throw new ServletException("The mode '" + mode + "' is unrecognized.");
//      }

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

      // process the request
      logger_.debug("file content type =" + upload_fi.getContentType());
      logger_.debug("file size = " + upload_fi.getSize());
      if (upload_fi.getSize() <= 0)
      {
        throw new PDFDocumentException(250, "The document is empty.");
      }
      byte[] document_bytes = upload_fi.get();

      VerificationFilter vf = new VerificationFilter();
      List signature_holders = null;
      
      String doc_file_name = upload_fi.getName();
      String extension = extractExtension(doc_file_name);

      String raw_text = null;
      if (doc_file_name == null || (extension != null && extension.equals("txt")))
      {
        raw_text = new String(document_bytes, "UTF-8");
        signature_holders = vf.extractSignaturesFromPlainText(raw_text);
      }
      else
      {
        signature_holders = vf.extractSignaturesFromPdf(document_bytes);
      }

      if (signature_holders.size() == 0)
      {
        throw new PDFDocumentException(206, "PDF document not signed.");
      }

      if (preview)
      {
        SessionInformation si = new SessionInformation();
        si.application = "verify";
        si.connector = connector;
        si.signature_holders = signature_holders;
        request.getSession().setAttribute(SessionAttributes.ATTRIBUTE_SESSION_INFORMATION, si);

        dispatch(request, response, "/jsp/verifylist.jsp");
        //VerifyPreview.formatPreview(signature_holders, connector, request, response);
      }
      else
      {
        if (ConnectorFactory.isConnectorLocal(connector))
        {
          SessionInformation si = new SessionInformation(); //SessionTable.generateSessionInformationObject();
          si.connector = connector;
          si.application = "verify";
          si.mode = null;
          si.pdf = null;
          si.type = null;
          si.user_name = null;
          si.user_password = null;
          
          si.signature_holders = signature_holders;

          LocalRequestHelper.processLocalVerify(si, si.signature_holders, request, response);
          dispatch(request, response, LocalRequestHelper.LOCAL_CONNECTION_PAGE_JSP);
          return;
        }

        List results = PdfAS.verifySignatureHolders(signature_holders, connector);
        dispatchToResults(results, request, response);
      }

    }
    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.jsp");
    }
    catch (PresentableException e)
    {
      e.printStackTrace();
      Sign.prepareDispatchToErrorPage(e, request);
      dispatch(request, response, "/jsp/error.jsp");
    }

  }

  /**
   * 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);
  }
}