/**
 * Copyright (c) 2010, Sebastian Sdorra
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of SCM-Manager; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://bitbucket.org/sdorra/scm-manager
 *
 */



package sonia.scm.filter;

//~--- non-JDK imports --------------------------------------------------------

import com.google.common.annotations.VisibleForTesting;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import sonia.scm.config.ScmConfiguration;
import sonia.scm.util.HttpUtil;
import sonia.scm.util.Util;
import sonia.scm.web.filter.HttpFilter;

//~--- JDK imports ------------------------------------------------------------

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Sebastian Sdorra
 */
@Singleton
public class BaseUrlFilter extends HttpFilter
{

  /**
   * Constructs ...
   *
   *
   * @param configuration
   */
  @Inject
  public BaseUrlFilter(ScmConfiguration configuration)
  {
    this.configuration = configuration;
  }

  //~--- methods --------------------------------------------------------------

  /**
   * Method description
   *
   *
   * @param requestUrl
   * @param baseUrl
   *
   * @return
   */
  @VisibleForTesting
  boolean startsWith(String requestUrl, String baseUrl)
  {
    return HttpUtil.normalizeUrl(requestUrl).startsWith(
      HttpUtil.normalizeUrl(baseUrl));
  }

  /**
   * Method description
   *
   *
   * @param request
   * @param response
   * @param chain
   *
   * @throws IOException
   * @throws ServletException
   */
  @Override
  protected void doFilter(HttpServletRequest request,
    HttpServletResponse response, FilterChain chain)
    throws IOException, ServletException
  {
    if (Util.isEmpty(configuration.getBaseUrl()))
    {
      configuration.setBaseUrl(createDefaultBaseUrl(request));
    }

    if (!configuration.isForceBaseUrl() || isBaseUrl(request))
    {
      chain.doFilter(request, response);
    }
    else
    {
      String url = HttpUtil.getCompleteUrl(configuration,
                     HttpUtil.getStrippedURI(request));

      response.sendRedirect(url);
    }
  }

  /**
   * Method description
   *
   *
   * @param request
   *
   * @return
   */
  private String createDefaultBaseUrl(HttpServletRequest request)
  {
    StringBuilder sb = new StringBuilder(request.getScheme());

    sb.append("://").append(request.getServerName()).append(":");
    sb.append(String.valueOf(request.getServerPort()));
    sb.append(request.getContextPath());

    return sb.toString();
  }

  //~--- get methods ----------------------------------------------------------

  /**
   * Method description
   *
   *
   * @param request
   *
   * @return
   */
  private boolean isBaseUrl(HttpServletRequest request)
  {
    return startsWith(request.getRequestURL().toString(),
      configuration.getBaseUrl());
  }

  //~--- fields ---------------------------------------------------------------

  /** Field description */
  private ScmConfiguration configuration;
}
