content: /*
   * Copyright (c) 2019 abc123lzf <abc123lzf@126.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  package com.lzf.flyingsocks.client.proxy.socks;
  
  import com.lzf.flyingsocks.client.proxy.ProxyRequest;
  import com.lzf.flyingsocks.client.proxy.ProxyRequestManager;
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.util.ReferenceCountUtil;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * @author lzf abc123lzf@126.com
   * @since 2021/1/14 4:04
   */
  public class UdpProxyMessageHandler extends ChannelInboundHandlerAdapter {
  
      private final ProxyRequestManager proxyRequestManager;
  
      private final Map<InetSocketAddress, ProxyRequest> requestCache = new HashMap<>();
  
      public UdpProxyMessageHandler(ProxyRequestManager proxyRequestManager) {
          this.proxyRequestManager = Objects.requireNonNull(proxyRequestManager);
      }
  
      @Override
      public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
          if (msg instanceof UdpProxyMessage) {
              try {
                  channelRead0(ctx, (UdpProxyMessage) msg);
              } finally {
                  ReferenceCountUtil.release(msg);
              }
          } else {
              ctx.fireChannelRead(msg);
          }
      }
  
  
      protected void channelRead0(ChannelHandlerContext ctx, UdpProxyMessage message) throws IOException {
          String host = message.getHost();
          int port = message.getPort();
          ByteBuf data = message.getData();
  
          InetSocketAddress address = new InetSocketAddress(host, port);
          ProxyRequest request = requestCache.get(address);
          if (request != null) {
              if (!request.isClose()) {
                  request.transferClientMessage(data);
                  return;
              }
  
              requestCache.remove(address);
          }
  
          request = new ProxyRequest(host, port, ctx.channel(), ProxyRequest.Protocol.UDP);
          requestCache.put(address, request);
          request.transferClientMessage(data);
          proxyRequestManager.publish(request);
  
          cleanClosedRequest();
      }
  
  
      private void cleanClosedRequest() {
          requestCache.values().removeIf(ProxyRequest::isClose);
      }
  
  
      @Override
      public void channelInactive(ChannelHandlerContext ctx) {
          requestCache.values().forEach(ProxyRequest::close);
          requestCache.clear();
      }
  }
  