/*
    * Copyright (c) 2002-2014, Mairie de Paris
    * 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
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' 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 COPYRIGHT HOLDERS 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.
   *
   * License 1.0
   */
  package fr.paris.lutece.portal.service.filter;
  
  import fr.paris.lutece.portal.service.init.LuteceInitException;
  import fr.paris.lutece.portal.service.plugin.Plugin;
  import fr.paris.lutece.portal.service.util.AppLogService;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import javax.servlet.Filter;
  import javax.servlet.ServletContext;
  
  
  /**
   * FilterService
   */
  public final class FilterService
  {
      private static FilterService _singleton = new FilterService(  );
      private static ServletContext _context;
      private List<LuteceFilter> _listFilters = new ArrayList<LuteceFilter>(  );
  
      /**
       * Private constructor
       */
      private FilterService(  )
      {
      }
  
      /**
       * Return the unique instance
       * @return The instance
       */
      public static FilterService getInstance(  )
      {
          return _singleton;
      }
  
      /**
       * Register a filter
       * @param entry The filter entry defined in the plugin's XML file
       * @param plugin The plugin
       */
      public void registerFilter( FilterEntry entry, Plugin plugin )
      {
          try
          {
              Filter filter = (Filter) Class.forName( entry.getFilterClass(  ) ).newInstance(  );
              LuteceFilter f = new LuteceFilter( entry.getName(  ), filter, entry.getMappingUrlPattern(  ), plugin,
                      entry.getInitParameters(  ) );
              f.setOrder( entry.getOrder(  ) );
              _listFilters.add( f );
              AppLogService.info( "New Filter registered : " + entry.getName(  ) );
  
              for ( String strKey : entry.getInitParameters(  ).keySet(  ) )
              {
                  AppLogService.info( " * init parameter - name : '" + strKey + "' - value : '" +
                      entry.getInitParameters(  ).get( strKey ) + "'" );
              }
          }
          catch ( InstantiationException e )
          {
              AppLogService.error( "Error registering a filter : " + e.getMessage(  ), e );
          }
          catch ( IllegalAccessException e )
         {
             AppLogService.error( "Error registering a filter : " + e.getMessage(  ), e );
         }
         catch ( ClassNotFoundException e )
         {
             AppLogService.error( "Error registering a filter : " + e.getMessage(  ), e );
         }
     }
 
     /**
      * Defines the servlet context used by the FilterConfig given to the filters
      * @param servletContext The context
      */
     public static void setServletContext( ServletContext servletContext )
     {
         _context = servletContext;
     }
 
     /**
      * Initializes filters
      * @param context The context
      * @throws LuteceInitException If an error occurs
      */
     public static void init( ServletContext context ) throws LuteceInitException
     {
         _context = context;
         AppLogService.info( "Initialize plugins filters" );
 
         for ( LuteceFilter filter : FilterService.getInstance(  ).getFilters(  ) )
         {
             // Catch exception for each filter to execute all chain
             try
             {
                 if ( filter.getPlugin(  ).isInstalled(  ) )
                 {
                     // Create a FilterConfig wrapper to provide init parameters to the filter
                     LuteceFilterConfig filterConfig = new LuteceFilterConfig( filter.getName(  ), _context,
                             filter.getInitParameters(  ) );
                     filter.getFilter(  ).init( filterConfig );
                     AppLogService.info( " * filter '" + filter.getName(  ) + "' from plugin " +
                         filter.getPlugin(  ).getName(  ) + " initialized." );
                 }
             }
             catch ( Exception e )
             {
                 AppLogService.error( "Error execution init() method - Filter " + filter.getName(  ), e );
                 throw new LuteceInitException( "Error execution init() method - Filter " + filter.getName(  ), e );
             }
         }
 
         sortFilters(  );
 
         if ( AppLogService.isDebugEnabled(  ) )
         {
             AppLogService.debug( "Displaying filters order" );
 
             for ( LuteceFilter filter : FilterService.getInstance(  ).getFilters(  ) )
             {
                 AppLogService.debug( filter.getName(  ) + " - order = " + filter.getOrder(  ) );
             }
         }
     }
 
     /**
      * Sort filters.
      */
     public static void sortFilters(  )
     {
         // sort the filter's list
         Collections.sort( FilterService.getInstance(  ).getFilters(  ) );
     }
 
     /**
      * Gives the filters list
      * @return The list of filters
      */
     public List<LuteceFilter> getFilters(  )
     {
         return _listFilters;
     }
 }