/*
    * 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.group;
  
  import org.jboss.netty.channel.Channel;
  import org.jboss.netty.channel.ChannelFuture;
  import org.jboss.netty.channel.ChannelFutureListener;
  import org.jboss.netty.logging.InternalLogger;
  import org.jboss.netty.logging.InternalLoggerFactory;
  import org.jboss.netty.util.internal.DeadLockProofWorker;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  
  import static java.util.concurrent.TimeUnit.*;
  
  /**
   * The default {@link ChannelGroupFuture} implementation.
   */
  public class DefaultChannelGroupFuture implements ChannelGroupFuture {
  
      private static final InternalLogger logger =
          InternalLoggerFactory.getInstance(DefaultChannelGroupFuture.class);
  
      private final ChannelGroup group;
      final Map<Integer, ChannelFuture> futures;
      private ChannelGroupFutureListener firstListener;
      private List<ChannelGroupFutureListener> otherListeners;
      private boolean done;
      int successCount;
      int failureCount;
      private int waiters;
  
      private final ChannelFutureListener childListener = new ChannelFutureListener() {
          public void operationComplete(ChannelFuture future) throws Exception {
              boolean success = future.isSuccess();
              boolean callSetDone;
              synchronized (DefaultChannelGroupFuture.this) {
                  if (success) {
                      successCount ++;
                  } else {
                      failureCount ++;
                  }
  
                  callSetDone = successCount + failureCount == futures.size();
                  assert successCount + failureCount <= futures.size();
              }
  
              if (callSetDone) {
                  setDone();
              }
          }
      };
  
      /**
       * Creates a new instance.
       */
      public DefaultChannelGroupFuture(ChannelGroup group, Collection<ChannelFuture> futures) {
          if (group == null) {
              throw new NullPointerException("group");
          }
          if (futures == null) {
              throw new NullPointerException("futures");
          }
  
          this.group = group;
  
          Map<Integer, ChannelFuture> futureMap = new LinkedHashMap<Integer, ChannelFuture>();
          for (ChannelFuture f: futures) {
              futureMap.put(f.getChannel().getId(), f);
          }
  
          this.futures = Collections.unmodifiableMap(futureMap);
  
          for (ChannelFuture f: this.futures.values()) {
              f.addListener(childListener);
          }
  
          // Done on arrival?
          if (this.futures.isEmpty()) {
             setDone();
         }
     }
 
     DefaultChannelGroupFuture(ChannelGroup group, Map<Integer, ChannelFuture> futures) {
         this.group = group;
         this.futures = Collections.unmodifiableMap(futures);
         for (ChannelFuture f: this.futures.values()) {
             f.addListener(childListener);
         }
 
         // Done on arrival?
         if (this.futures.isEmpty()) {
             setDone();
         }
     }
 
     public ChannelGroup getGroup() {
         return group;
     }
 
     public ChannelFuture find(Integer channelId) {
         return futures.get(channelId);
     }
 
     public ChannelFuture find(Channel channel) {
         return futures.get(channel.getId());
     }
 
     public Iterator<ChannelFuture> iterator() {
         return futures.values().iterator();
     }
 
     public synchronized boolean isDone() {
         return done;
     }
 
     public synchronized boolean isCompleteSuccess() {
         return successCount == futures.size();
     }
 
     public synchronized boolean isPartialSuccess() {
         return successCount != 0 && successCount != futures.size();
     }
 
     public synchronized boolean isPartialFailure() {
         return failureCount != 0 && failureCount != futures.size();
     }
 
     public synchronized boolean isCompleteFailure() {
         int futureCnt = futures.size();
         return futureCnt != 0 && failureCount == futureCnt;
     }
 
     public void addListener(ChannelGroupFutureListener listener) {
         if (listener == null) {
             throw new NullPointerException("listener");
         }
 
         boolean notifyNow = false;
         synchronized (this) {
             if (done) {
                 notifyNow = true;
             } else {
                 if (firstListener == null) {
                     firstListener = listener;
                 } else {
                     if (otherListeners == null) {
                         otherListeners = new ArrayList<ChannelGroupFutureListener>(1);
                     }
                     otherListeners.add(listener);
                 }
             }
         }
 
         if (notifyNow) {
             notifyListener(listener);
         }
     }
 
     public void removeListener(ChannelGroupFutureListener listener) {
         if (listener == null) {
             throw new NullPointerException("listener");
         }
 
         synchronized (this) {
             if (!done) {
                 if (listener == firstListener) {
                     if (otherListeners != null && !otherListeners.isEmpty()) {
                         firstListener = otherListeners.remove(0);
                     } else {
                         firstListener = null;
                     }
                 } else if (otherListeners != null) {
                     otherListeners.remove(listener);
                 }
             }
         }
     }
 
     public ChannelGroupFuture await() throws InterruptedException {
         if (Thread.interrupted()) {
             throw new InterruptedException();
         }
 
         synchronized (this) {
             while (!done) {
                 checkDeadLock();
                 waiters++;
                 try {
                     wait();
                 } finally {
                     waiters--;
                 }
             }
         }
         return this;
     }
 
     public boolean await(long timeout, TimeUnit unit)
             throws InterruptedException {
         return await0(unit.toNanos(timeout), true);
     }
 
     public boolean await(long timeoutMillis) throws InterruptedException {
         return await0(MILLISECONDS.toNanos(timeoutMillis), true);
     }
 
     public ChannelGroupFuture awaitUninterruptibly() {
         boolean interrupted = false;
         synchronized (this) {
             while (!done) {
                 checkDeadLock();
                 waiters++;
                 try {
                     wait();
                 } catch (InterruptedException e) {
                     interrupted = true;
                 } finally {
                     waiters--;
                 }
             }
         }
 
         if (interrupted) {
             Thread.currentThread().interrupt();
         }
 
         return this;
     }
 
     public boolean awaitUninterruptibly(long timeout, TimeUnit unit) {
         try {
             return await0(unit.toNanos(timeout), false);
         } catch (InterruptedException e) {
             throw new InternalError();
         }
     }
 
     public boolean awaitUninterruptibly(long timeoutMillis) {
         try {
             return await0(MILLISECONDS.toNanos(timeoutMillis), false);
         } catch (InterruptedException e) {
             throw new InternalError();
         }
     }
 
     private boolean await0(long timeoutNanos, boolean interruptable) throws InterruptedException {
         if (interruptable && Thread.interrupted()) {
             throw new InterruptedException();
         }
 
         long startTime = timeoutNanos <= 0 ? 0 : System.nanoTime();
         long waitTime = timeoutNanos;
         boolean interrupted = false;
 
         try {
             synchronized (this) {
                 if (done || waitTime <= 0) {
                     return done;
                 }
 
                 checkDeadLock();
                 waiters++;
                 try {
                     for (;;) {
                         try {
                             wait(waitTime / 1000000, (int) (waitTime % 1000000));
                         } catch (InterruptedException e) {
                             if (interruptable) {
                                 throw e;
                             } else {
                                 interrupted = true;
                             }
                         }
 
                         if (done) {
                             return true;
                         } else {
                             waitTime = timeoutNanos - (System.nanoTime() - startTime);
                             if (waitTime <= 0) {
                                 return done;
                             }
                         }
                     }
                 } finally {
                     waiters--;
                 }
             }
         } finally {
             if (interrupted) {
                 Thread.currentThread().interrupt();
             }
         }
     }
 
     private static void checkDeadLock() {
         if (DeadLockProofWorker.PARENT.get() != null) {
             throw new IllegalStateException(
                     "await*() in I/O thread causes a dead lock or " +
                     "sudden performance drop. Use addListener() instead or " +
                     "call await*() from a different thread.");
         }
     }
 
     boolean setDone() {
         synchronized (this) {
             // Allow only once.
             if (done) {
                 return false;
             }
 
             done = true;
             if (waiters > 0) {
                 notifyAll();
             }
         }
 
         notifyListeners();
         return true;
     }
 
     private void notifyListeners() {
         // This method doesn't need synchronization because:
         // 1) This method is always called after synchronized (this) block.
         //    Hence any listener list modification happens-before this method.
         // 2) This method is called only when 'done' is true.  Once 'done'
         //    becomes true, the listener list is never modified - see add/removeListener()
         if (firstListener != null) {
             notifyListener(firstListener);
             firstListener = null;
 
             if (otherListeners != null) {
                 for (ChannelGroupFutureListener l: otherListeners) {
                     notifyListener(l);
                 }
                 otherListeners = null;
             }
         }
     }
 
     private void notifyListener(ChannelGroupFutureListener l) {
         try {
             l.operationComplete(this);
         } catch (Throwable t) {
             if (logger.isWarnEnabled()) {
                 logger.warn(
                         "An exception was thrown by " +
                         ChannelFutureListener.class.getSimpleName() + '.', t);
             }
         }
     }
 }