package at.knowcenter.wag.egov.egiz.web.servlets;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.servlet.RequestDispatcher;
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.logging.Log;
import org.apache.commons.logging.LogFactory;

import at.gv.egiz.pdfas.web.SignSessionInformation;
import at.gv.egiz.pdfas.web.helper.SignServletHelper;
import at.knowcenter.wag.egov.egiz.exceptions.PresentableException;
import at.knowcenter.wag.egov.egiz.web.FormFields;
import at.knowcenter.wag.egov.egiz.web.PDFContainer;
import at.knowcenter.wag.egov.egiz.web.SessionAttributes;

public class ProvidePDFServlet extends HttpServlet {

   /**
    * SVUID.
    */
   private static final long serialVersionUID = 1L;

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

   public static Set signedDocuments = Collections.synchronizedSet(new HashSet());

   public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      
      String pdfIdString = request.getParameter(FormFields.FIELD_PDF_ID);
      
      if (pdfIdString == null) {
         HttpSession session = request.getSession(true);
         log.debug("No " + FormFields.FIELD_PDF_ID + " provided. Trying to retrieve PDF from session (" + session.getId() + ").");
         SignSessionInformation si = (SignSessionInformation) session.getAttribute(SessionAttributes.SIGNED_PDF_DOCUMENT);
         if (si == null) {
            log.warn("Unable to find signed pdf in session (" + session.getId() + ").");
            SignServlet.prepareDispatchToErrorPage(new PresentableException(600, "Das signierte Dokument konnte nicht gefunden werden."), request);
            response.setContentType("text/html");
            response.setCharacterEncoding("UTF-8");
            RequestDispatcher disp = super.getServletContext().getRequestDispatcher("/jsp/error.jsp");
            disp.forward(request, response);
            return;
         } else {
            log.debug("Signed pdf found.");
            session.removeAttribute(SessionAttributes.SIGNED_PDF_DOCUMENT);
            log.debug("Returning signed pdf to browser.");
            log.debug("Invalidating session.");
            session.invalidate();
            SignServletHelper.returnSignResponse(si, response);
            return;
         }
      } else {
         long pdfId = Long.parseLong(pdfIdString);

         Iterator it = signedDocuments.iterator();

         while (it.hasNext()) {
            PDFContainer current = (PDFContainer) it.next();
            if (current.id == pdfId) {
               try {
                  byte[] pdf = current.pdf;

                  response.setContentType("application/pdf");
                  response.setContentLength(pdf.length);

                  InputStream is = new ByteArrayInputStream(pdf);
                  final int bufferSize = 1024;
                  byte[] buffer = new byte[bufferSize];
                  int len = -1;
                  while ((len = is.read(buffer)) != -1) {
                     response.getOutputStream().write(buffer, 0, len);
                  }
                  response.getOutputStream().flush();
                  signedDocuments.remove(current);
               } catch (IOException e) {
                  log.warn("IO excepton while providing pdf document: " + e.getMessage());
               }
            }
         }
      }

   }

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

}