/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF licenses this file
    *  to you under the Apache License, Version 2.0 (the
    *  "License"); you may not use this file except in compliance
    *  with the License.  You may obtain a copy of the License at
    *  
   *    http://www.apache.org/licenses/LICENSE-2.0
   *  
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License. 
   *  
   */
  package org.apache.directory.server.dhcp.store;
  
  
  import java.net.InetAddress;
  import java.net.UnknownHostException;
  import java.util.Arrays;
  
  
  /**
   * The definition of a Subnet.
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class Subnet extends DhcpConfigElement
  {
      /** the subnet's address */
      private final InetAddress address;
  
      /** the subnet's netmask */
      private final InetAddress netmask;
  
      /** the subnet's range: minimum address in range */
      private InetAddress rangeMin;
  
      /** the subnet's range: maximum address in range */
      private InetAddress rangeMax;
  
  
      // This will suppress PMD.EmptyCatchBlock warnings in this method
      @SuppressWarnings("PMD.EmptyCatchBlock")
      public Subnet( InetAddress address, InetAddress netmask, InetAddress rangeMin, InetAddress rangeMax )
      {
          // mask address to match subnet
          byte[] masked = netmask.getAddress();
          byte[] addrBytes = netmask.getAddress();
  
          for ( int i = 0; i < addrBytes.length; i++ )
          {
              masked[i] &= addrBytes[i];
          }
  
          if ( !Arrays.equals( masked, addrBytes ) )
          {
              try
              {
                  address = InetAddress.getByAddress( masked );
              }
              catch ( UnknownHostException e )
              {
                  // ignore - doesn't happen.
              }
          }
  
          this.address = address;
          this.netmask = netmask;
          this.rangeMin = rangeMin;
          this.rangeMax = rangeMax;
      }
  
  
      public InetAddress getAddress()
      {
          return address;
      }
  
  
      public InetAddress getNetmask()
      {
          return netmask;
      }
  
  
      public InetAddress getRangeMax()
      {
          return rangeMax;
      }
  
  
      public void setRangeMax( InetAddress rangeMax )
      {
         this.rangeMax = rangeMax;
     }
 
 
     public InetAddress getRangeMin()
     {
         return rangeMin;
     }
 
 
     public void setRangeMin( InetAddress rangeMin )
     {
         this.rangeMin = rangeMin;
     }
 
 
     /**
      * Check whether the given client address resides within this subnet and
      * possibly range.
      * 
      * @param clientAddress
      * @return boolean
      */
     public boolean contains( InetAddress clientAddress )
     {
         // check address type
         if ( !clientAddress.getClass().equals( address.getClass() ) )
         {
             return false;
         }
 
         byte[] client = clientAddress.getAddress();
         byte[] masked = netmask.getAddress();
 
         for ( int i = 0; i < masked.length; i++ )
         {
             masked[i] &= client[i];
         }
 
         return Arrays.equals( masked, address.getAddress() );
     }
 
 
     /**
      * Check whether the specified address is within the range for this subnet.
      * 
      * @param clientAddress
      * @return boolean
      */
     public boolean isInRange( InetAddress clientAddress )
     {
         byte[] client = clientAddress.getAddress();
         byte[] masked = netmask.getAddress();
 
         for ( int i = 0; i < masked.length; i++ )
         {
             masked[i] &= client[i];
         }
 
         if ( null != rangeMin && arrayComp( masked, rangeMin.getAddress() ) < 0 )
         {
             return false;
         }
 
         return ( null == rangeMin || arrayComp( masked, rangeMax.getAddress() ) <= 0 );
     }
 
 
     private static int arrayComp( byte[] a1, byte[] a2 )
     {
         for ( int i = 0; i < a1.length && i < a2.length; i++ )
         {
             if ( a1[i] != a2[i] )
             {
                 return ( a1[i] & 0xff ) - ( a2[i] & 0xff );
             }
         }
 
         return a1.length - a2.length;
     }
 }