/**
 * <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: Sign.java,v 1.7 2006/10/11 07:39:13 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.web;

import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.util.Iterator;
import java.util.List;

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

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.PdfASID;
import at.knowcenter.wag.egov.egiz.cfg.ConfigLogger;
import at.knowcenter.wag.egov.egiz.cfg.SettingsReader;
import at.knowcenter.wag.egov.egiz.exceptions.ErrorCodeException;
import at.knowcenter.wag.egov.egiz.exceptions.PDFDocumentException;
import at.knowcenter.wag.egov.egiz.exceptions.PlaceholderException;
import at.knowcenter.wag.egov.egiz.exceptions.PresentableException;
import at.knowcenter.wag.egov.egiz.framework.SignResult;
import at.knowcenter.wag.egov.egiz.framework.Signator;
import at.knowcenter.wag.egov.egiz.framework.SignatorFactory;
import at.knowcenter.wag.egov.egiz.framework.signators.DetachedSignator_1_0_0;
import at.knowcenter.wag.egov.egiz.sig.ConnectorFactory;
import at.knowcenter.wag.egov.egiz.tools.CodingHelper;

/**
 * This method is the sign 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 sign process
 * 
 * @author wlackner
 * @author wprinz
 */
public class Sign extends HttpServlet
{

  /**
   * SVUID.
   */
  private static final long serialVersionUID = -4156938216903740438L;

  /**
   * Authorisation marker for the http header string.
   */
  protected static final String AUTH = "authorization";

  /**
   * Authorisation marker for the http header string.
   */
  protected static final String AUTH_BASIC = "Basic";

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

  protected void dispatch(HttpServletRequest request,
      HttpServletResponse response, String resource) throws ServletException, IOException
  {
    dispatch(request, response, resource, getServletContext());
  }

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

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

  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    String authenticate = request.getHeader(AUTH);
    if (authenticate != null)
    {
      logger_.info("authenticate:" + authenticate);
      if (authenticate.indexOf(AUTH_BASIC) == 0)
      {
        authenticate = authenticate.substring(AUTH_BASIC.length() + 1);
        logger_.info("authenticate:" + authenticate);
        authenticate = new String(CodingHelper.decodeBase64(authenticate), "UTF-8");
        logger_.info("authenticate:" + authenticate);

        String[] auth_value = authenticate.split(":");
        String user_name = auth_value[0];
        String user_password = auth_value[1];
        logger_.info("username:" + user_name);
        logger_.info("password:" + user_password);

        HttpSession session = request.getSession();
        session.setAttribute(SessionAttributes.ATTRIBUTE_USER_NAME, user_name);
        session.setAttribute(SessionAttributes.ATTRIBUTE_USER_PASSWORD, user_password);

        dispatch(request, response, "/jsp/signupload.jsp");
        return;
      }
    }

    request.setAttribute("error", "Falsche Authentifikation");
    request.setAttribute("cause", "Passwort oder Benutzername ist falsch");
    dispatch(request, response, "/jsp/error.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 preview_fi = null;
      FileItem sig_type_fi = null;
      FileItem sig_app_fi = null;
      FileItem mode_fi = null;
      FileItem file_upload_fi = null;
      FileItem download_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_PREVIEW))
        {
          preview_fi = item;
          continue;
        }

        if (item.getFieldName().equals(FormFields.FIELD_SIGNATURE_TYPE))
        {
          sig_type_fi = item;
          continue;
        }

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

        if (item.getFieldName().equals(FormFields.FIELD_MODE))
        {
          mode_fi = item;
          continue;
        }

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

        if (item.getFieldName().equals(FormFields.FIELD_DOWNLOAD))
        {
          download_fi = item;
          continue;
        }

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

      }

      if (preview_fi == null || sig_type_fi == null || sig_app_fi == null || file_upload_fi == null || download_fi == null)
      {
        throw new ServletException("Unsufficient data provided in request");
      }

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

      String preview_str = preview_fi.getString("UTF-8");
      boolean preview = false;
      if (preview_str.equals("true"))
      {
        preview = true;
      }

      boolean download_inline = true;
      if (download_fi.getString("UTF-8").equals(FormFields.VALUE_DOWNLOAD_ATTACHMENT))
      {
        download_inline = false;
      }

      String sig_type = sig_type_fi.getString("UTF-8");
      String connector = sig_app_fi.getString("UTF-8");

      String doc_file_name = file_upload_fi.getName();
      logger_.debug("  file content type =" + file_upload_fi.getContentType());

      String extension = Verify.extractExtension(doc_file_name);
      if (extension != null && !extension.equals("pdf"))
      {
        throw new PDFDocumentException(201, "The provided file '" + doc_file_name + "' doesn't have the PDF extension (.pdf).");
      }

      byte[] pdf = file_upload_fi.get();
      if (file_upload_fi.getSize() <= 0)
      {
        throw new PDFDocumentException(250, "The document is empty.");
      }
      PdfAS.applyStrictMode(pdf);

      String user_name = (String) request.getSession().getAttribute(SessionAttributes.ATTRIBUTE_USER_NAME);
      String user_password = (String) request.getSession().getAttribute(SessionAttributes.ATTRIBUTE_USER_PASSWORD);

      SessionInformation si = new SessionInformation(); // SessionTable.generateSessionInformationObject();
      si.connector = connector;
      si.application = "sign";
      si.mode = mode;
      si.pdf = pdf;
      si.type = sig_type;
      si.user_name = user_name;
      si.user_password = user_password;
      si.filename = formatFileName(file_upload_fi.getName());
      si.download_inline = download_inline;

      prepareSign(si);

      if (preview)
      {
        request.getSession().setAttribute(SessionAttributes.ATTRIBUTE_SESSION_INFORMATION, si);

        String submit_url = response.encodeURL(request.getContextPath() + "/SignPreview");

        request.setAttribute("submit_url", submit_url);

        dispatch(request, response, "/jsp/signpreview.jsp");

        return;
      }

      finishSign(si, request, response, getServletContext());
    }
    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();
      prepareDispatchToErrorPage(e, request);
      dispatch(request, response, "/jsp/error.jsp");
    }
  }

  public static void prepareSign(SessionInformation si) throws PresentableException
  {
    PdfASID algorithm = FormFields.translateSignatureModeToPdfASID(si.mode);
    Signator signator = SignatorFactory.createSignator(algorithm);
    si.iui = signator.prepareSign(si.pdf, si.type, null, ConnectorFactory.needsSIG_ID(si.connector));
  }

  public static void finishSign(SessionInformation si,
      HttpServletRequest request, HttpServletResponse response, ServletContext context) throws PresentableException, IOException, ServletException
  {
    if (ConnectorFactory.isConnectorLocal(si.connector))
    {
      LocalRequestHelper.processLocalSign(si, request, response);
      dispatch(request, response, LocalRequestHelper.LOCAL_CONNECTION_PAGE_JSP, context);
      return;
    }

    PdfASID algorithm = FormFields.translateSignatureModeToPdfASID(si.mode);
    Signator signator = SignatorFactory.createSignator(algorithm);

    si.iui.signed_signature_object = PdfAS.sign(si.iui.document_text, si.type, si.connector, si.user_name, si.user_password);

    si.sign_result = signator.finishSign(si.iui);

    returnSignResponse(si, response);
  }

  public static void prepareDispatchToErrorPage(PresentableException pe,
      HttpServletRequest request)
  {
    if (pe instanceof ErrorCodeException)
    {
      ErrorCodeException ece = (ErrorCodeException) pe;
      request.setAttribute("error", "Fehler " + ece.getErrorCode());

      String cause = ece.getErrorCodeMessage();
      if (ece.hasExternalErrorMessage())
      {
        cause = ece.getExternalErrorCode() + ": " + ece.getExternalErrorMessage();
      }
      request.setAttribute("cause", cause);

      if (pe instanceof PlaceholderException)
      {
        PlaceholderException phe = (PlaceholderException) ece;

        request.setAttribute("cause", "Der Platzhalter des Feldes " + phe.getField() + " ist um " + phe.getMissing() + " Bytes zu kurz. " + ece.getErrorCodeMessage());
      }
    }
    else
    {
      request.setAttribute("error", "PresentableException");
      request.setAttribute("cause", pe.toString());
    }
  }

  public void dispatchToPreview(String document_text, String connector,
      String mode, String signature_type, String submit_url,
      HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    request.setAttribute("document_text", document_text);
    request.setAttribute("connector", connector);
    request.setAttribute("mode", mode);
    request.setAttribute("signature_type", signature_type);
    request.setAttribute("submit_url", submit_url);

    dispatch(request, response, "/jsp/signpreview.jsp");
  }

  // public static void formatPreview(String document_text, String connector,
  // String mode, String signature_type, String submit_url,
  // HttpServletResponse response) throws ServletException, IOException
  // {
  // response.setContentType("text/html");
  // response.setCharacterEncoding("UTF-8");
  //
  // PrintWriter writer = response.getWriter();
  //
  // writer.println("<html>");
  // writer.println("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0
  // Transitional//EN\"
  // \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">");
  // writer.println("<html>");
  // writer.println("<head>");
  // writer.println("<meta http-equiv=\"content-type\" content=\"text/html;
  // charset=UTF-8\" />");
  // writer.println("<title>PDF-AS Amtssignaturen Vorschau</title>");
  // writer.println("<link rel=\"stylesheet\" type=\"text/css\"
  // href=\"/pdf-as/css/styles.css\" />");
  // writer.println("</head>");
  //
  // writer.println("<body>");
  // writer.println("<div>");
  //
  // writer.println("<h1>PDF-AS Amtssignaturen</h1>");
  //
  // writer.println("<div id=\"nav\">");
  // writer.println("<div id=\"nh\">Vorschau: Dokument Pr&uuml;fen</div>");
  // writer.println("<form action=\"" + submit_url + "\"");
  // writer.println(" name=\"submitform\"");
  // writer.println(" enctype=\"multipart/form-data\"");
  // writer.println(" accept-charset=\"UTF-8\"");
  // writer.println(" method=\"post\">");
  // writer.println("<div id=\"ct\">");
  //
  // writer.println("<input type=\"hidden\" name=\"" + FormFields.FIELD_PREVIEW
  // + "\" value=\"" + FormFields.VALUE_FALSE + "\" />");
  // writer.println("<input type=\"hidden\" name=\"" +
  // FormFields.FIELD_SIGNATURE_TYPE + "\" value=\"" + signature_type + "\"
  // />");
  // writer.println("<input type=\"hidden\" name=\"" +
  // FormFields.FIELD_CONNECTOR + "\" value=\"" + connector + "\" />");
  // writer.println("<input type=\"hidden\" name=\"" + FormFields.FIELD_MODE +
  // "\" value=\"" + mode + "\" />");
  // writer.println("<input type=\"hidden\" name=\"" + "after_preview" + "\"
  // value=\"" + "yes" + "\" />");
  //
  // writer.println("<textarea class=\"pr\" cols=\"80\" rows=\"14\" name=\"" +
  // FormFields.FIELD_UPLOAD + "\" readonly=\"readonly\">" + document_text +
  // "</textarea>");
  // writer.println("<br/>");
  //
  // writer.println("<input class=\"ip\" type=\"submit\" value=\"Signieren...\"
  // />");
  //
  // writer.println("</div>");
  // writer.println("</form>");
  // writer.println("</div>");
  //
  // writer.println("<a class=\"big\" href=\"/pdf-as/\">zurück</a>");
  //
  // writer.println("</div>");
  // writer.println("</body>");
  //
  // writer.println("</html>");
  // }

  /**
   * This class is just used to put the pdf byte array into the session.
   * 
   * @author wprinz
   */
  protected class SignPreviewInfo implements Serializable
  {
    /**
     * SVUID.
     */
    private static final long serialVersionUID = 3102824040163616332L;

    public byte[] pdf = null;

    public String mode = null;
  }

  /**
   * Formats the file name so that it is suitable for content disposition.
   * 
   * @param file_name
   *          The file name.
   * @return Returns the formatted file name.
   */
  public static String formatFileName(String file_name)
  {
    File file = new File(file_name);
    String file_name_only = file.getName();
    // the file_name contains \\ ==> remove them so Internet Explorer works
    // correctly.
    return file_name_only;
  }

  /**
   * Formats the file name according to the SignResult.
   * 
   * @param file_name
   *          The file name.
   * @param sign_result
   *          The sign result.
   * @return Returns the formatted file name.
   */
  public static String formatFileNameForSignResult(String file_name,
      SignResult sign_result)
  {
    String output = file_name + "_signed";
    if (sign_result.getMimeType().equals(DetachedSignator_1_0_0.MIME_TYPE))
    {
      output += ".xml";
    }
    else
    {
      output += ".pdf";
    }

    return output;
  }

  /**
   * Returns the data in the SignResult with proper content disposition.
   * 
   * @param si
   *          SessionInformation.
   * @param response
   *          The servlet response.
   * @throws IOException
   *           The IO Exception.
   */
  public static void returnSignResponse(SessionInformation si,
      HttpServletResponse response) throws IOException
  {
    SignResult sign_result = si.sign_result;
    
    String file_name = formatFileNameForSignResult(si.filename, sign_result);

    // The name parameter is actually deprecated in favour of Content-Disposition filename
    // Unfortunately Acrobat reader does recognize neither of these parameters
    // with its inline save-as. It always takes the page name.
    response.setContentType(sign_result.getMimeType() + "; name=\"" + file_name + "\"");
    if (si.download_inline)
    {
      response.addHeader("Content-Disposition", "inline; filename=\"" + file_name + "\"");
    }
    else
    {
      response.addHeader("Content-Disposition", "attachment; filename=\"" + file_name + "\"");
    }
    response.getOutputStream().write(sign_result.getData());

  }
}