/*
    * 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.buffer.ByteBufAllocator;
  import io.netty.channel.ChannelException;
  import io.netty.channel.ChannelOption;
  import io.netty.channel.MessageSizeEstimator;
  import io.netty.channel.RecvByteBufAllocator;
  import io.netty.util.NetUtil;
  
  import java.io.IOException;
  import java.util.Map;
  
  import static io.netty.channel.ChannelOption.SO_BACKLOG;
  import static io.netty.channel.ChannelOption.SO_RCVBUF;
  import static io.netty.channel.ChannelOption.SO_REUSEADDR;
  
  public class EpollServerChannelConfig extends EpollChannelConfig {
      protected final AbstractEpollChannel channel;
      private volatile int backlog = NetUtil.SOMAXCONN;
      private volatile int pendingFastOpenRequestsThreshold;
  
      EpollServerChannelConfig(AbstractEpollChannel channel) {
          super(channel);
          this.channel = channel;
      }
  
      @Override
      public Map<ChannelOption<?>, Object> getOptions() {
          return getOptions(super.getOptions(), SO_RCVBUF, SO_REUSEADDR, SO_BACKLOG, EpollChannelOption.TCP_FASTOPEN);
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public <T> T getOption(ChannelOption<T> option) {
          if (option == SO_RCVBUF) {
              return (T) Integer.valueOf(getReceiveBufferSize());
          }
          if (option == SO_REUSEADDR) {
              return (T) Boolean.valueOf(isReuseAddress());
          }
          if (option == SO_BACKLOG) {
              return (T) Integer.valueOf(getBacklog());
          }
          if (option == EpollChannelOption.TCP_FASTOPEN) {
              return (T) Integer.valueOf(getTcpFastopen());
          }
          return super.getOption(option);
      }
  
      @Override
      public <T> boolean setOption(ChannelOption<T> option, T value) {
          validate(option, value);
  
          if (option == SO_RCVBUF) {
              setReceiveBufferSize((Integer) value);
          } else if (option == SO_REUSEADDR) {
              setReuseAddress((Boolean) value);
          } else if (option == SO_BACKLOG) {
              setBacklog((Integer) value);
          } else if (option == EpollChannelOption.TCP_FASTOPEN) {
              setTcpFastopen((Integer) value);
          } else {
              return super.setOption(option, value);
          }
  
          return true;
      }
  
      public boolean isReuseAddress() {
          try {
              return Native.isReuseAddress(channel.fd().intValue()) == 1;
          } catch (IOException e) {
              throw new ChannelException(e);
          }
      }
  
      public EpollServerChannelConfig setReuseAddress(boolean reuseAddress) {
          try {
              Native.setReuseAddress(channel.fd().intValue(), reuseAddress ? 1 : 0);
              return this;
          } catch (IOException e) {
              throw new ChannelException(e);
          }
      }
 
     public int getReceiveBufferSize() {
         try {
             return channel.fd().getReceiveBufferSize();
         } catch (IOException e) {
             throw new ChannelException(e);
         }
     }
 
     public EpollServerChannelConfig setReceiveBufferSize(int receiveBufferSize) {
         try {
             channel.fd().setReceiveBufferSize(receiveBufferSize);
             return this;
         } catch (IOException e) {
             throw new ChannelException(e);
         }
     }
 
     public int getBacklog() {
         return backlog;
     }
 
     public EpollServerChannelConfig setBacklog(int backlog) {
         if (backlog < 0) {
             throw new IllegalArgumentException("backlog: " + backlog);
         }
         this.backlog = backlog;
         return this;
     }
 
     /**
      * Returns threshold value of number of pending for fast open connect.
      *
      * @see <a href="https://tools.ietf.org/html/rfc7413#appendix-A.2">RFC 7413 Passive Open</a>
      */
     public int getTcpFastopen() {
         return pendingFastOpenRequestsThreshold;
     }
 
     /**
      * Enables tcpFastOpen on the server channel. If the underlying os doesnt support TCP_FASTOPEN setting this has no
      * effect. This has to be set before doing listen on the socket otherwise this takes no effect.
      *
      * @param pendingFastOpenRequestsThreshold number of requests to be pending for fastopen at a given point in time
      * for security. @see <a href="https://tools.ietf.org/html/rfc7413#appendix-A.2">RFC 7413 Passive Open</a>
      *
      * @see <a href="https://tools.ietf.org/html/rfc7413">RFC 7413 TCP FastOpen</a>
      */
     public EpollServerChannelConfig setTcpFastopen(int pendingFastOpenRequestsThreshold) {
         if (this.pendingFastOpenRequestsThreshold < 0) {
             throw new IllegalArgumentException("pendingFastOpenRequestsThreshold: " + pendingFastOpenRequestsThreshold);
         }
         this.pendingFastOpenRequestsThreshold = pendingFastOpenRequestsThreshold;
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setConnectTimeoutMillis(int connectTimeoutMillis) {
         super.setConnectTimeoutMillis(connectTimeoutMillis);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setMaxMessagesPerRead(int maxMessagesPerRead) {
         super.setMaxMessagesPerRead(maxMessagesPerRead);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setWriteSpinCount(int writeSpinCount) {
         super.setWriteSpinCount(writeSpinCount);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setAllocator(ByteBufAllocator allocator) {
         super.setAllocator(allocator);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setRecvByteBufAllocator(RecvByteBufAllocator allocator) {
         super.setRecvByteBufAllocator(allocator);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setAutoRead(boolean autoRead) {
         super.setAutoRead(autoRead);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setWriteBufferHighWaterMark(int writeBufferHighWaterMark) {
         super.setWriteBufferHighWaterMark(writeBufferHighWaterMark);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setWriteBufferLowWaterMark(int writeBufferLowWaterMark) {
         super.setWriteBufferLowWaterMark(writeBufferLowWaterMark);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setMessageSizeEstimator(MessageSizeEstimator estimator) {
         super.setMessageSizeEstimator(estimator);
         return this;
     }
 
     @Override
     public EpollServerChannelConfig setEpollMode(EpollMode mode) {
         super.setEpollMode(mode);
         return this;
     }
 }