/**
    * This file Copyright (c) 2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.ui;
  
  import info.magnolia.cms.core.AggregationState;
  import info.magnolia.cms.filters.AbstractMgnlFilter;
  import info.magnolia.cms.filters.FilterManager;
  import info.magnolia.cms.security.User;
  import info.magnolia.cms.util.ServletUtil;
  import info.magnolia.context.Context;
  import info.magnolia.context.MgnlContext;
  import info.magnolia.context.WebContextImpl;
  import info.magnolia.module.ModuleManagementException;
  import info.magnolia.module.ModuleManager;
  
  import java.io.IOException;
  import java.io.Writer;
  import java.util.Locale;
  
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.lang3.StringUtils;
  
  /**
   * Filter responsible for executing the update/install mechanism.
   */
  public class InstallationFilter extends AbstractMgnlFilter {
      private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(InstallationFilter.class);
  
      private final ModuleManager moduleManager;
      private final FilterManager filterManager;
      private ServletContext servletContext;
  
      public InstallationFilter(ModuleManager moduleManager, FilterManager filterManager) {
          this.moduleManager = moduleManager;
          this.filterManager = filterManager;
      }
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
          super.init(filterConfig);
          servletContext = filterConfig.getServletContext();
      }
  
      @Override
      public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
          // this isn't the cleanest thing, but we're basically tricking FreemarkerHelper into using a Context, while avoiding using WebContextImpl and its depedencies on the repository
          final Context originalContext = MgnlContext.hasInstance() ? MgnlContext.getInstance() : null;
          final InstallWebContext ctx = new InstallWebContext();
          ctx.init(request, response, servletContext);
          MgnlContext.setInstance(ctx);
  
          try {
              final String contextPath = request.getContextPath();
              // TODO : this will be invalid the day we allow other resources (css, images) to be served through the installer
              response.setContentType("text/html");
              final Writer out = response.getWriter();
              final String uri = ServletUtil.stripPathParameters(request.getRequestURI());
              final ModuleManagerUI ui = moduleManager.getUI();
  
              final String prefix = contextPath + ModuleManagerWebUI.INSTALLER_PATH;
              if (uri.startsWith(prefix)) {
                  final String command = StringUtils.defaultIfEmpty(StringUtils.substringAfter(uri, prefix + "/"), null);
                 final boolean installDone = ui.execute(out, command);
                 if (installDone) {
                     filterManager.startUsingConfiguredFilters();
                     // invalidate session: MAGNOLIA-2611
                     request.getSession().invalidate();
                     // redirect to root
                     response.sendRedirect(contextPath + "/");
                 }
             } else {
                 // redirect to /.magnolia/installer - even if it has no concrete effect, the change in the browser's url bar makes this more explicit
                 response.sendRedirect(prefix);
             }
         } catch (ModuleManagementException e) {
             log.error(e.getMessage(), e);
             throw new RuntimeException(e); // TODO
         } finally {
             MgnlContext.release();
             MgnlContext.setInstance(originalContext);
         }
     }
 
     private final static class InstallWebContext extends WebContextImpl {
         @Override
         public User getUser() {
             return null;
         }
 
         @Override
         public Locale getLocale() {
             return MgnlContext.getSystemContext().getLocale();
         }
 
         @Override
         protected AggregationState newAggregationState() {
             throw new IllegalStateException("AggregationState is not meant to be used during the installation process.");
         }
     }
 }