/*
 * Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.server.webapp;

import com.caucho.servlet.comet.CometFilterChain;
import com.caucho.server.http.AbstractHttpRequest;
import com.caucho.server.http.AbstractHttpResponse;
import com.caucho.server.http.CauchoResponse;
import com.caucho.server.http.HttpServletRequestImpl;
import com.caucho.server.http.HttpServletResponseImpl;
import com.caucho.server.log.AbstractAccessLog;
import com.caucho.transaction.TransactionManagerImpl;
import com.caucho.transaction.UserTransactionImpl;
import com.caucho.transaction.UserTransactionProxy;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Represents the next filter in a filter chain.  The final filter will
 * be the servlet itself.
 */
public class WebAppFilterChain implements CauchoFilterChain {
  private static final Logger log
    = Logger.getLogger(WebAppFilterChain.class.getName());

  // Next filter chain
  private FilterChain _next;

  // app
  private WebApp _webApp;
  // transaction manager
  private TransactionManagerImpl _tm;
  // transaction proxy
  private UserTransactionProxy _utm;
  // error page manager
  private ErrorPageManager _errorPageManager;

  // true it's the top
  private boolean _isTop = true;

  /**
   * Creates a new FilterChainFilter.
   *
   * @param next the next filterChain
   * @param filter the user's filter
   */
  public WebAppFilterChain(FilterChain next, WebApp app)
  {
    this(next, app, true);
  }

  /**
   * Creates a new FilterChainFilter.
   *
   * @param next the next filterChain
   * @param filter the user's filter
   */
  public WebAppFilterChain(FilterChain next, WebApp webApp, boolean isTop)
  {
    _next = next;
    _webApp = webApp;
    _errorPageManager = webApp.getErrorPageManager();
    _isTop = isTop;

    try {
      if (_isTop) {
        _tm = TransactionManagerImpl.getInstance();
        _utm = UserTransactionProxy.getInstance();
      }
    } catch (Throwable e) {
      log.log(Level.WARNING, e.toString(), e);
    }
  }

  /**
   * Returns true if cacheable.
   */
  public FilterChain getNext()
  {
    return _next;
  }

  /**
   * Invokes the next filter in the chain or the final servlet at
   * the end of the chain.
   *
   * @param request the servlet request
   * @param response the servlet response
   * @since Servlet 2.3
   */
  @Override
  public void doFilter(ServletRequest request,
                       ServletResponse response)
    throws ServletException, IOException
  {
    Thread thread = Thread.currentThread();
    ClassLoader oldLoader = thread.getContextClassLoader();

    WebApp webApp = _webApp;

    UserTransactionImpl ut = null;
    if (_isTop)
      ut = _utm.getUserTransaction();

    try {
      thread.setContextClassLoader(webApp.getClassLoader());

      if (! webApp.enterWebApp() && webApp.getConfigException() == null) {
        if (response instanceof HttpServletResponse) {
          HttpServletResponse res = (HttpServletResponse) response;

          res.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
        }

        return;
      }

      _next.doFilter(request, response);
    } catch (Throwable e) {
      _errorPageManager.sendServletError(e, request, response);
    } finally {
      webApp.exitWebApp();

      // put finish() before access log so the session isn't tied up while
      // logging

      // needed for things like closing the session
      if (request instanceof HttpServletRequestImpl)
        ((HttpServletRequestImpl) request).finishInvocation();

      // server/1ld5
      if (_isTop) {
        ((CauchoResponse) response).close();

        try {
          if (ut != null)
            ut.abortTransaction();
        } catch (Throwable e) {
          log.log(Level.WARNING, e.toString(), e);
        }
      }

      thread.setContextClassLoader(oldLoader);
    }
  }

  @Override
  public String toString()
  {
    return (getClass().getSimpleName()
            + "[" + _webApp.getURL()
            + ", next=" + _next + "]");
  }
}