/*
    * Copyright 2015 The Netty Project
    *
    * The Netty Project 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 io.netty.channel.epoll;
  
  import io.netty.util.internal.ObjectUtil;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Map;
  import java.util.Map.Entry;
  
  final class TcpMd5Util {
  
      static Collection<InetAddress> newTcpMd5Sigs(AbstractEpollChannel channel, Collection<InetAddress> current,
                                           Map<InetAddress, byte[]> newKeys) throws IOException {
          ObjectUtil.checkNotNull(channel, "channel");
          ObjectUtil.checkNotNull(current, "current");
          ObjectUtil.checkNotNull(newKeys, "newKeys");
  
          // Validate incoming values
          for (Entry<InetAddress, byte[]> e : newKeys.entrySet()) {
              final byte[] key = e.getValue();
              if (e.getKey() == null) {
                  throw new IllegalArgumentException("newKeys contains an entry with null address: " + newKeys);
              }
              if (key == null) {
                  throw new NullPointerException("newKeys[" + e.getKey() + ']');
              }
              if (key.length == 0) {
                  throw new IllegalArgumentException("newKeys[" + e.getKey() + "] has an empty key.");
              }
              if (key.length > Native.TCP_MD5SIG_MAXKEYLEN) {
                  throw new IllegalArgumentException("newKeys[" + e.getKey() +
                      "] has a key with invalid length; should not exceed the maximum length (" +
                          Native.TCP_MD5SIG_MAXKEYLEN + ')');
              }
          }
  
          // Remove mappings not present in the new set.
          for (InetAddress addr : current) {
              if (!newKeys.containsKey(addr)) {
                  Native.setTcpMd5Sig(channel.fd().intValue(), addr, null);
              }
          }
  
          if (newKeys.isEmpty()) {
              return Collections.emptySet();
          }
  
          // Set new mappings and store addresses which we set.
          final Collection<InetAddress> addresses = new ArrayList<InetAddress>(newKeys.size());
          for (Entry<InetAddress, byte[]> e : newKeys.entrySet()) {
              Native.setTcpMd5Sig(channel.fd().intValue(), e.getKey(), e.getValue());
              addresses.add(e.getKey());
          }
  
          return addresses;
      }
  
      private TcpMd5Util() {
      }
  }