/*
    * Copyright 2012 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.example.socksproxy;
  
  import io.netty.channel.ChannelHandler;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.SimpleChannelInboundHandler;
  import io.netty.handler.codec.socks.SocksAuthResponse;
  import io.netty.handler.codec.socks.SocksAuthScheme;
  import io.netty.handler.codec.socks.SocksAuthStatus;
  import io.netty.handler.codec.socks.SocksCmdRequest;
  import io.netty.handler.codec.socks.SocksCmdRequestDecoder;
  import io.netty.handler.codec.socks.SocksCmdType;
  import io.netty.handler.codec.socks.SocksInitResponse;
  import io.netty.handler.codec.socks.SocksRequest;
  
  
  @ChannelHandler.Sharable
  public final class SocksServerHandler extends SimpleChannelInboundHandler<SocksRequest> {
  
      @Override
      public void channelRead0(ChannelHandlerContext ctx, SocksRequest socksRequest) throws Exception {
          switch (socksRequest.requestType()) {
              case INIT: {
                  // auth support example
                  //ctx.pipeline().addFirst(new SocksAuthRequestDecoder());
                  //ctx.write(new SocksInitResponse(SocksAuthScheme.AUTH_PASSWORD));
                  ctx.pipeline().addFirst(new SocksCmdRequestDecoder());
                  ctx.write(new SocksInitResponse(SocksAuthScheme.NO_AUTH));
                  break;
              }
              case AUTH:
                  ctx.pipeline().addFirst(new SocksCmdRequestDecoder());
                  ctx.write(new SocksAuthResponse(SocksAuthStatus.SUCCESS));
                  break;
              case CMD:
                  SocksCmdRequest req = (SocksCmdRequest) socksRequest;
                  if (req.cmdType() == SocksCmdType.CONNECT) {
                      ctx.pipeline().addLast(new SocksServerConnectHandler());
                      ctx.pipeline().remove(this);
                      ctx.fireChannelRead(socksRequest);
                  } else {
                      ctx.close();
                  }
                  break;
              case UNKNOWN:
                  ctx.close();
                  break;
          }
      }
  
      @Override
      public void channelReadComplete(ChannelHandlerContext ctx) {
          ctx.flush();
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable throwable) {
          throwable.printStackTrace();
          SocksServerUtils.closeOnFlush(ctx.channel());
      }
  }