/*
    * Copyright (c) 2002-2021, City of 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.util.signrequest.servlet;
  
  import fr.paris.lutece.util.signrequest.AbstractAuthenticator;
  import fr.paris.lutece.util.signrequest.AbstractPrivateKeyAuthenticator;
  import fr.paris.lutece.util.signrequest.security.Sha1HashService;
  
  import java.io.IOException;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.StringTokenizer;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  /**
   * SimpleHash Sign Request Filter
   */
  public abstract class AbstractRequestFilter implements Filter
  {
      private static final String PARAMETER_PRIVATE_KEY = "privateKey";
      private static final String PARAMETER_ELEMENTS_SIGNATURE = "elementsSignature";
      private static final String PARAMETER_VALIDITY_PERIOD = "validityTimePeriod";
      private AbstractAuthenticator _authenticator;
  
      /**
       * The implementation should provide the authenticator to use
       * 
       * @return The authenticator to be used by the filter
       */
      protected abstract AbstractAuthenticator getAuthenticator( );
  
      /**
       * {@inheritDoc }
       */
      @Override
      public void init( FilterConfig filterConfig ) throws ServletException
      {
          _authenticator = getAuthenticator( );
  
          // Set the Hashing service
          _authenticator.setHashService( new Sha1HashService( ) );
  
          if ( _authenticator instanceof AbstractPrivateKeyAuthenticator )
          {
              // Set the shared secret between client and server
              String strPrivateKey = filterConfig.getInitParameter( PARAMETER_PRIVATE_KEY );
              ( (AbstractPrivateKeyAuthenticator) _authenticator ).setPrivateKey( strPrivateKey );
          }
  
          // Set the list of elements that compose the signature
          String strElementsList = filterConfig.getInitParameter( PARAMETER_ELEMENTS_SIGNATURE );
          StringTokenizer st = new StringTokenizer( strElementsList, "," );
          List<String> listElements = new ArrayList<String>( );
  
          while ( st.hasMoreTokens( ) )
          {
              listElements.add( st.nextToken( ).trim( ) );
          }
  
         _authenticator.setSignatureElements( listElements );
 
         // Sets The validity Time Period
         String strValidityTimePeriod = filterConfig.getInitParameter( PARAMETER_VALIDITY_PERIOD );
         _authenticator.setValidityTimePeriod( Long.parseLong( strValidityTimePeriod ) );
     }
 
     /**
      * {@inheritDoc }
      */
     @Override
     public void doFilter( ServletRequest request, ServletResponse response, FilterChain chain ) throws IOException, ServletException
     {
         if ( _authenticator.isRequestAuthenticated( (HttpServletRequest) request ) )
         {
             chain.doFilter( request, response );
         }
         else
         {
             ( (HttpServletResponse) response ).setStatus( HttpServletResponse.SC_UNAUTHORIZED );
         }
     }
 
     /**
      * {@inheritDoc }
      */
     @Override
     public void destroy( )
     {
     }
 }