/*
 * Copyright 2008 Federal Chancellery Austria and
 * Graz University of Technology
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package at.gv.egiz.bku.online.webapp;

import java.io.IOException;
import java.util.Iterator;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
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.bku.binding.HTTPBindingProcessor;
import at.gv.egiz.bku.binding.HttpUtil;
import at.gv.egiz.bku.binding.IdFactory;
import at.gv.egiz.bku.conf.Configurator;
import at.gv.egiz.bku.utils.NullOutputStream;

/**
 * Delivers the result to the browser
 * 
 */
public class ResultServlet extends SpringBKUServlet {

  private final static Log log = LogFactory.getLog(ResultServlet.class);

  private String encoding = "UTF-8";
  private String expiredPage = "./expiredError.jsp";

  public ResultServlet() {
  }

  private void myInit() {
    String enc = getServletContext().getInitParameter("responseEncoding");
    if (enc != null) {
      log.debug("Init default encoding to: " + enc);
      encoding = enc;
    }
    String expP = getServletConfig().getInitParameter("expiredPage");
    if (expP != null) {
      log.debug("Init expired page to: " + expP);
      expiredPage = expP;
    }
  }

  @Override
  public void init() throws ServletException {
    super.init();
    myInit();
  }

  @Override
  public void init(ServletConfig config) throws ServletException {
    super.init(config);
    myInit();
  }

  protected void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
    doGet(req, resp);
  }

  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, java.io.IOException {

    HttpSession session = req.getSession(false);
    if (session == null) {
      resp.sendRedirect(expiredPage);
      return;
    }
    String sessionId = session.getId();
    if (sessionId == null) {
      resp.sendRedirect(expiredPage);
      return;
    }
    log.debug("Got a result request for session: " + sessionId);
    HTTPBindingProcessor bp = (HTTPBindingProcessor) getBindingProcessorManager()
        .getBindingProcessor(IdFactory.getInstance().createId(sessionId));
    if (bp == null) {
      session.invalidate();
      resp.sendRedirect(expiredPage);
      return;
    }
    String redirectUrl = (String) session
        .getAttribute(BKURequestHandler.REDIRECT_URL_SESSION_ATTRIBUTE);
    if (redirectUrl == null) {
      redirectUrl = bp.getRedirectURL();
    }
    if (redirectUrl != null) {
      try {
        bp.writeResultTo(new NullOutputStream(), encoding);
        getBindingProcessorManager().removeBindingProcessor(bp.getId());
      } finally {
        log.info("Executing deferred browser redirect to: " + redirectUrl);
        resp.sendRedirect(redirectUrl);
        session.invalidate();
      }
      return;
    }
    resp.setStatus(bp.getResponseCode());
    resp.setHeader("Cache-Control", "no-store"); // HTTP 1.1
    resp.setHeader("Pragma", "no-cache"); // HTTP 1.0
    resp.setDateHeader("Expires", 0);
    if (configurator.getProperty(Configurator.USERAGENT_CONFIG_P) != null) {
      resp.setHeader(HttpUtil.HTTP_HEADER_USER_AGENT, configurator
          .getProperty(Configurator.USERAGENT_CONFIG_P));
    } else {
      resp.setHeader(HttpUtil.HTTP_HEADER_USER_AGENT,
              Configurator.USERAGENT_DEFAULT);
    }
    for (Iterator<String> it = bp.getResponseHeaders().keySet().iterator(); it
        .hasNext();) {
      String header = it.next();
      resp.setHeader(header, bp.getResponseHeaders().get(header));
    }
    resp.setContentType(bp.getResultContentType());
    resp.setCharacterEncoding(encoding);
    bp.writeResultTo(resp.getOutputStream(), encoding);
    resp.getOutputStream().flush();
    session.invalidate();
    getBindingProcessorManager().removeBindingProcessor(bp.getId());
  }
}