/*
    * 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 org.jboss.netty.channel.socket.nio;
  
  import org.jboss.netty.channel.Channel;
  import org.jboss.netty.channel.ChannelFuture;
  import org.jboss.netty.util.ThreadNameDeterminer;
  import org.jboss.netty.util.ThreadRenamingRunnable;
  import org.jboss.netty.util.Timeout;
  import org.jboss.netty.util.Timer;
  import org.jboss.netty.util.TimerTask;
  
  import java.io.IOException;
  import java.net.ConnectException;
  import java.nio.channels.ClosedChannelException;
  import java.nio.channels.SelectionKey;
  import java.nio.channels.Selector;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.concurrent.Executor;
  import java.util.concurrent.TimeUnit;
  
  import static org.jboss.netty.channel.Channels.*;
  
  /**
   * {@link Boss} implementation that handles the  connection attempts of clients
   */
  public final class NioClientBoss extends AbstractNioSelector implements Boss {
  
      private final TimerTask wakeupTask = new TimerTask() {
          public void run(Timeout timeout) throws Exception {
              // This is needed to prevent a possible race that can lead to a NPE
              // when the selector is closed before this is run
              //
              // See https://github.com/netty/netty/issues/685
              Selector selector = NioClientBoss.this.selector;
  
              if (selector != null) {
                  if (wakenUp.compareAndSet(false, true)) {
                      selector.wakeup();
                  }
              }
          }
      };
  
      private final Timer timer;
  
      NioClientBoss(Executor bossExecutor, Timer timer, ThreadNameDeterminer determiner) {
          super(bossExecutor, determiner);
          this.timer = timer;
      }
  
      @Override
      protected ThreadRenamingRunnable newThreadRenamingRunnable(int id, ThreadNameDeterminer determiner) {
          return new ThreadRenamingRunnable(this, "New I/O boss #" + id, determiner);
      }
  
      @Override
      protected Runnable createRegisterTask(Channel channel, ChannelFuture future) {
          return new RegisterTask(this, (NioClientSocketChannel) channel);
      }
  
      @Override
      protected void process(Selector selector) {
          processSelectedKeys(selector.selectedKeys());
  
          // Handle connection timeout every 10 milliseconds approximately.
          long currentTimeNanos = System.nanoTime();
          processConnectTimeout(selector.keys(), currentTimeNanos);
      }
  
      private void processSelectedKeys(Set<SelectionKey> selectedKeys) {
  
          // check if the set is empty and if so just return to not create garbage by
          // creating a new Iterator every time even if there is nothing to process.
          // See https://github.com/netty/netty/issues/597
          if (selectedKeys.isEmpty()) {
              return;
          }
          for (Iterator<SelectionKey> i = selectedKeys.iterator(); i.hasNext();) {
              SelectionKey k = i.next();
              i.remove();
  
              if (!k.isValid()) {
                  close(k);
                  continue;
             }
 
             try {
                 if (k.isConnectable()) {
                     connect(k);
                 }
             } catch (Throwable t) {
                 NioClientSocketChannel ch = (NioClientSocketChannel) k.attachment();
                 ch.connectFuture.setFailure(t);
                 fireExceptionCaught(ch, t);
                 k.cancel(); // Some JDK implementations run into an infinite loop without this.
                 ch.worker.close(ch, succeededFuture(ch));
             }
         }
     }
 
     private static void processConnectTimeout(Set<SelectionKey> keys, long currentTimeNanos) {
         ConnectException cause = null;
         for (SelectionKey k: keys) {
             if (!k.isValid()) {
                 // Comment the close call again as it gave us major problems
                 // with ClosedChannelExceptions.
                 //
                 // See:
                 // * https://github.com/netty/netty/issues/142
                 // * https://github.com/netty/netty/issues/138
                 //
                 // close(k);
                 continue;
             }
 
             NioClientSocketChannel ch = (NioClientSocketChannel) k.attachment();
             if (ch.connectDeadlineNanos > 0 &&
                     currentTimeNanos >= ch.connectDeadlineNanos) {
 
                 if (cause == null) {
                     cause = new ConnectException("connection timed out");
                 }
 
                 ch.connectFuture.setFailure(cause);
                 fireExceptionCaught(ch, cause);
                 ch.worker.close(ch, succeededFuture(ch));
             }
         }
     }
 
     private static void connect(SelectionKey k) throws IOException {
         NioClientSocketChannel ch = (NioClientSocketChannel) k.attachment();
         if (ch.channel.finishConnect()) {
             k.cancel();
             if (ch.timoutTimer != null) {
                 ch.timoutTimer.cancel();
             }
             ch.worker.register(ch, ch.connectFuture);
         }
     }
 
     @Override
     protected void close(SelectionKey k) {
         NioClientSocketChannel ch = (NioClientSocketChannel) k.attachment();
         ch.worker.close(ch, succeededFuture(ch));
     }
 
     private final class RegisterTask implements Runnable {
         private final NioClientBoss boss;
         private final NioClientSocketChannel channel;
 
         RegisterTask(NioClientBoss boss, NioClientSocketChannel channel) {
             this.boss = boss;
             this.channel = channel;
         }
 
         public void run() {
             int timeout = channel.getConfig().getConnectTimeoutMillis();
             if (timeout > 0) {
                 if (!channel.isConnected()) {
                     channel.timoutTimer = timer.newTimeout(wakeupTask,
                             timeout, TimeUnit.MILLISECONDS);
                 }
             }
             try {
                 channel.channel.register(
                         boss.selector, SelectionKey.OP_CONNECT, channel);
             } catch (ClosedChannelException e) {
                 channel.worker.close(channel, succeededFuture(channel));
             }
 
             int connectTimeout = channel.getConfig().getConnectTimeoutMillis();
             if (connectTimeout > 0) {
                 channel.connectDeadlineNanos = System.nanoTime() + connectTimeout * 1000000L;
             }
         }
     }
 }