/*
    * 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:
    *
    *   https://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.netty5.channel.group;
  
  import io.netty5.channel.Channel;
  import io.netty5.util.concurrent.BlockingOperationException;
  import io.netty5.util.concurrent.DefaultPromise;
  import io.netty5.util.concurrent.EventExecutor;
  import io.netty5.util.concurrent.Future;
  import io.netty5.util.concurrent.FutureListener;
  import io.netty5.util.concurrent.ImmediateEventExecutor;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  
  /**
   * The default {@link ChannelGroupFuture} implementation.
   */
  final class DefaultChannelGroupFuture extends DefaultPromise<Void> implements ChannelGroupFuture {
  
      private final ChannelGroup group;
      private final Map<Channel, Future<Void>> futures;
      private int successCount;
      private int failureCount;
  
      private final FutureListener<Void> childListener = new FutureListener<>() {
          @Override
          public void operationComplete(Future<? extends Void> 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) {
                  if (failureCount > 0) {
                      List<Map.Entry<Channel, Throwable>> failed =
                              new ArrayList<>(failureCount);
                      for (Entry<Channel, Future<Void>> entry: futures.entrySet()) {
                          if (entry.getValue().isFailed()) {
                              failed.add(new DefaultEntry<>(entry.getKey(), entry.getValue().cause()));
                          }
                      }
                      setFailure0(new ChannelGroupException(failed));
                  } else {
                      setSuccess0();
                  }
              }
          }
      };
  
      DefaultChannelGroupFuture(ChannelGroup group, Map<Channel, Future<Void>> futures, EventExecutor executor) {
          super(executor);
          this.group = group;
          this.futures = Collections.unmodifiableMap(futures);
          for (Future<Void> f: this.futures.values()) {
              f.addListener(childListener);
          }
  
          // Done on arrival?
          if (this.futures.isEmpty()) {
              setSuccess0();
          }
      }
  
      @Override
      public ChannelGroup group() {
          return group;
      }
  
      @Override
      public Future<Void> find(Channel channel) {
          return futures.get(channel);
      }
  
     @Override
     public Iterator<Future<Void>> iterator() {
         return futures.values().iterator();
     }
 
     @Override
     public synchronized boolean isPartialSuccess() {
         return successCount != 0 && successCount != futures.size();
     }
 
     @Override
     public synchronized boolean isPartialFailure() {
         return failureCount != 0 && failureCount != futures.size();
     }
 
     @Override
     public DefaultChannelGroupFuture addListener(FutureListener<? super Void> listener) {
         super.addListener(listener);
         return this;
     }
 
     @Override
     public DefaultChannelGroupFuture await() throws InterruptedException {
         super.await();
         return this;
     }
 
     @Override
     public ChannelGroupException cause() {
         return (ChannelGroupException) super.cause();
     }
 
     private void setSuccess0() {
         super.setSuccess(null);
     }
 
     private void setFailure0(ChannelGroupException cause) {
         super.setFailure(cause);
     }
 
     @Override
     public DefaultChannelGroupFuture setSuccess(Void result) {
         throw new IllegalStateException();
     }
 
     @Override
     public boolean trySuccess(Void result) {
         throw new IllegalStateException();
     }
 
     @Override
     public DefaultChannelGroupFuture setFailure(Throwable cause) {
         throw new IllegalStateException();
     }
 
     @Override
     public boolean tryFailure(Throwable cause) {
         throw new IllegalStateException();
     }
 
     @Override
     protected void checkDeadLock() {
         EventExecutor e = executor();
         if (e != null && e != ImmediateEventExecutor.INSTANCE && e.inEventLoop()) {
             throw new BlockingOperationException();
         }
     }
 
     private static final class DefaultEntry<K, V> implements Map.Entry<K, V> {
         private final K key;
         private final V value;
 
         DefaultEntry(K key, V value) {
             this.key = key;
             this.value = value;
         }
 
         @Override
         public K getKey() {
             return key;
         }
 
         @Override
         public V getValue() {
             return value;
         }
 
         @Override
         public V setValue(V value) {
             throw new UnsupportedOperationException("read-only");
         }
     }
 }