/*
    * Copyright 2011 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:
    *
    * https://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.sctp.nio;
  
  import com.sun.nio.sctp.SctpChannel;
  import com.sun.nio.sctp.SctpServerChannel;
  import io.netty.channel.ChannelException;
  import io.netty.channel.ChannelFuture;
  import io.netty.channel.ChannelMetadata;
  import io.netty.channel.ChannelOutboundBuffer;
  import io.netty.channel.ChannelPromise;
  import io.netty.channel.nio.AbstractNioMessageChannel;
  import io.netty.channel.sctp.DefaultSctpServerChannelConfig;
  import io.netty.channel.sctp.SctpServerChannelConfig;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  import java.nio.channels.SelectionKey;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Set;
  
  /**
   * {@link io.netty.channel.sctp.SctpServerChannel} implementation which use non-blocking mode to accept new
   * connections and create the {@link NioSctpChannel} for them.
   *
   * Be aware that not all operations systems support SCTP. Please refer to the documentation of your operation system,
   * to understand what you need to do to use it. Also this feature is only supported on Java 7+.
   */
  public class NioSctpServerChannel extends AbstractNioMessageChannel
          implements io.netty.channel.sctp.SctpServerChannel {
      private static final ChannelMetadata METADATA = new ChannelMetadata(false, 16);
  
      private static SctpServerChannel newSocket() {
          try {
              return SctpServerChannel.open();
          } catch (IOException e) {
              throw new ChannelException(
                      "Failed to open a server socket.", e);
          }
      }
  
      private final SctpServerChannelConfig config;
  
      /**
       * Create a new instance
       */
      public NioSctpServerChannel() {
          super(null, newSocket(), SelectionKey.OP_ACCEPT);
          config = new NioSctpServerChannelConfig(this, javaChannel());
      }
  
      @Override
      public ChannelMetadata metadata() {
          return METADATA;
      }
  
      @Override
      public Set<InetSocketAddress> allLocalAddresses() {
          try {
              final Set<SocketAddress> allLocalAddresses = javaChannel().getAllLocalAddresses();
              final Set<InetSocketAddress> addresses = new LinkedHashSet<InetSocketAddress>(allLocalAddresses.size());
              for (SocketAddress socketAddress : allLocalAddresses) {
                  addresses.add((InetSocketAddress) socketAddress);
              }
              return addresses;
          } catch (Throwable ignored) {
              return Collections.emptySet();
          }
      }
  
      @Override
      public SctpServerChannelConfig config() {
          return config;
      }
  
      @Override
      public boolean isActive() {
          return isOpen() && !allLocalAddresses().isEmpty();
      }
  
      @Override
     public InetSocketAddress remoteAddress() {
         return null;
     }
 
     @Override
     public InetSocketAddress localAddress() {
         return (InetSocketAddress) super.localAddress();
     }
 
     @Override
     protected SctpServerChannel javaChannel() {
         return (SctpServerChannel) super.javaChannel();
     }
 
     @Override
     protected SocketAddress localAddress0() {
         try {
             Iterator<SocketAddress> i = javaChannel().getAllLocalAddresses().iterator();
             if (i.hasNext()) {
                 return i.next();
             }
         } catch (IOException e) {
             // ignore
         }
         return null;
     }
 
     @Override
     protected void doBind(SocketAddress localAddress) throws Exception {
         javaChannel().bind(localAddress, config.getBacklog());
     }
 
     @Override
     protected void doClose() throws Exception {
         javaChannel().close();
     }
 
     @Override
     protected int doReadMessages(List<Object> buf) throws Exception {
         SctpChannel ch = javaChannel().accept();
         if (ch == null) {
             return 0;
         }
         buf.add(new NioSctpChannel(this, ch));
         return 1;
     }
 
     @Override
     public ChannelFuture bindAddress(InetAddress localAddress) {
         return bindAddress(localAddress, newPromise());
     }
 
     @Override
     public ChannelFuture bindAddress(final InetAddress localAddress, final ChannelPromise promise) {
         if (eventLoop().inEventLoop()) {
             try {
                 javaChannel().bindAddress(localAddress);
                 promise.setSuccess();
             } catch (Throwable t) {
                 promise.setFailure(t);
             }
         } else {
             eventLoop().execute(new Runnable() {
                 @Override
                 public void run() {
                     bindAddress(localAddress, promise);
                 }
             });
         }
         return promise;
     }
 
     @Override
     public ChannelFuture unbindAddress(InetAddress localAddress) {
         return unbindAddress(localAddress, newPromise());
     }
 
     @Override
     public ChannelFuture unbindAddress(final InetAddress localAddress, final ChannelPromise promise) {
         if (eventLoop().inEventLoop()) {
             try {
                 javaChannel().unbindAddress(localAddress);
                 promise.setSuccess();
             } catch (Throwable t) {
                 promise.setFailure(t);
             }
         } else {
             eventLoop().execute(new Runnable() {
                 @Override
                 public void run() {
                     unbindAddress(localAddress, promise);
                 }
             });
         }
         return promise;
     }
 
     // Unnecessary stuff
     @Override
     protected boolean doConnect(
             SocketAddress remoteAddress, SocketAddress localAddress) throws Exception {
         throw new UnsupportedOperationException();
     }
 
     @Override
     protected void doFinishConnect() throws Exception {
         throw new UnsupportedOperationException();
     }
 
     @Override
     protected SocketAddress remoteAddress0() {
         return null;
     }
 
     @Override
     protected void doDisconnect() throws Exception {
         throw new UnsupportedOperationException();
     }
 
     @Override
     protected boolean doWriteMessage(Object msg, ChannelOutboundBuffer in) throws Exception {
         throw new UnsupportedOperationException();
     }
 
     @Override
     protected Object filterOutboundMessage(Object msg) throws Exception {
         throw new UnsupportedOperationException();
     }
 
     private final class NioSctpServerChannelConfig extends DefaultSctpServerChannelConfig {
         private NioSctpServerChannelConfig(NioSctpServerChannel channel, SctpServerChannel javaChannel) {
             super(channel, javaChannel);
         }
 
         @Override
         protected void autoReadCleared() {
             clearReadPending();
         }
     }
 }