/*
    * 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.bootstrap;
  
  import io.netty5.channel.Channel;
  import io.netty5.channel.ChannelFactory;
  import io.netty5.channel.ChannelFutureListeners;
  import io.netty5.channel.ChannelPipeline;
  import io.netty5.channel.EventLoop;
  import io.netty5.channel.EventLoopGroup;
  import io.netty5.channel.ReflectiveChannelFactory;
  import io.netty5.resolver.AddressResolver;
  import io.netty5.resolver.AddressResolverGroup;
  import io.netty5.resolver.DefaultAddressResolverGroup;
  import io.netty5.resolver.NameResolver;
  import io.netty5.util.concurrent.Future;
  import io.netty5.util.concurrent.Promise;
  import io.netty5.util.internal.logging.InternalLogger;
  import io.netty5.util.internal.logging.InternalLoggerFactory;
  
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A {@link Bootstrap} that makes it easy to bootstrap a {@link Channel} to use
   * for clients.
   *
   * <p>The {@link #bind()} methods are useful in combination with connectionless transports such as datagram (UDP).
   * For regular TCP connections, please use the provided {@link #connect()} methods.</p>
   */
  public class Bootstrap extends AbstractBootstrap<Bootstrap, Channel, ChannelFactory<? extends Channel>> {
  
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(Bootstrap.class);
  
      private static final AddressResolverGroup<?> DEFAULT_RESOLVER = DefaultAddressResolverGroup.INSTANCE;
  
      private final BootstrapConfig config = new BootstrapConfig(this);
  
      @SuppressWarnings("unchecked")
      private volatile AddressResolverGroup<SocketAddress> resolver =
              (AddressResolverGroup<SocketAddress>) DEFAULT_RESOLVER;
      private volatile SocketAddress remoteAddress;
      volatile ChannelFactory<? extends Channel> channelFactory;
  
      public Bootstrap() { }
  
      private Bootstrap(Bootstrap bootstrap) {
          super(bootstrap);
          resolver = bootstrap.resolver;
          remoteAddress = bootstrap.remoteAddress;
          channelFactory = bootstrap.channelFactory;
      }
  
      /**
       * Sets the {@link NameResolver} which will resolve the address of the unresolved named address.
       *
       * @param resolver the {@link NameResolver} for this {@code Bootstrap}; may be {@code null}, in which case a default
       *                 resolver will be used
       *
       * @see DefaultAddressResolverGroup
       */
      @SuppressWarnings("unchecked")
      public Bootstrap resolver(AddressResolverGroup<?> resolver) {
          this.resolver = (AddressResolverGroup<SocketAddress>) (resolver == null ? DEFAULT_RESOLVER : resolver);
          return this;
      }
  
      /**
       * The {@link SocketAddress} to connect to once the {@link #connect()} method
       * is called.
       */
      public Bootstrap remoteAddress(SocketAddress remoteAddress) {
          this.remoteAddress = remoteAddress;
          return this;
      }
  
      /**
       * @see #remoteAddress(SocketAddress)
       */
      public Bootstrap remoteAddress(String inetHost, int inetPort) {
          remoteAddress = InetSocketAddress.createUnresolved(inetHost, inetPort);
          return this;
      }
 
     /**
      * @see #remoteAddress(SocketAddress)
      */
     public Bootstrap remoteAddress(InetAddress inetHost, int inetPort) {
         remoteAddress = new InetSocketAddress(inetHost, inetPort);
         return this;
     }
 
     /**
      * The {@link Class} which is used to create {@link Channel} instances from.
      * You either use this or {@link #channelFactory(ChannelFactory)} if your
      * {@link Channel} implementation has no no-args constructor.
      */
     public Bootstrap channel(Class<? extends Channel> channelClass) {
         requireNonNull(channelClass, "channelClass");
         return channelFactory(new ReflectiveChannelFactory<Channel>(channelClass));
     }
 
     /**
      * {@link ChannelFactory} which is used to create {@link Channel} instances from
      * when calling {@link #bind()}. This method is usually only used if {@link #channel(Class)}
      * is not working for you because of some more complex needs. If your {@link Channel} implementation
      * has a no-args constructor, its highly recommend to just use {@link #channel(Class)} to
      * simplify your code.
      */
     public Bootstrap channelFactory(ChannelFactory<? extends Channel> channelFactory) {
         requireNonNull(channelFactory, "channelFactory");
         if (this.channelFactory != null) {
             throw new IllegalStateException("channelFactory set already");
         }
 
         this.channelFactory = channelFactory;
         return this;
     }
 
     /**
      * Connect a {@link Channel} to the remote peer.
      */
     public Future<Channel> connect() {
         validate();
         SocketAddress remoteAddress = this.remoteAddress;
         if (remoteAddress == null) {
             throw new IllegalStateException("remoteAddress not set");
         }
 
         return doResolveAndConnect(remoteAddress, config.localAddress());
     }
 
     /**
      * Connect a {@link Channel} to the remote peer.
      */
     public Future<Channel> connect(String inetHost, int inetPort) {
         return connect(InetSocketAddress.createUnresolved(inetHost, inetPort));
     }
 
     /**
      * Connect a {@link Channel} to the remote peer.
      */
     public Future<Channel> connect(InetAddress inetHost, int inetPort) {
         return connect(new InetSocketAddress(inetHost, inetPort));
     }
 
     /**
      * Connect a {@link Channel} to the remote peer.
      */
     public Future<Channel> connect(SocketAddress remoteAddress) {
         requireNonNull(remoteAddress, "remoteAddress");
 
         validate();
         return doResolveAndConnect(remoteAddress, config.localAddress());
     }
 
     /**
      * Connect a {@link Channel} to the remote peer.
      */
     public Future<Channel> connect(SocketAddress remoteAddress, SocketAddress localAddress) {
         requireNonNull(remoteAddress, "remoteAddress");
         validate();
         return doResolveAndConnect(remoteAddress, localAddress);
     }
 
     /**
      * @see #connect()
      */
     private Future<Channel> doResolveAndConnect(final SocketAddress remoteAddress, final SocketAddress localAddress) {
         EventLoop loop = group.next();
         final Future<Channel> regFuture = initAndRegister(loop);
 
         Promise<Channel> resolveAndConnectPromise = loop.newPromise();
         if (regFuture.isDone()) {
             if (regFuture.isFailed()) {
                 return regFuture;
             }
             Channel channel = regFuture.getNow();
             doResolveAndConnect0(channel, remoteAddress, localAddress, resolveAndConnectPromise);
         } else {
             // Registration future is almost always fulfilled already, but just in case it's not.
             regFuture.addListener(future -> {
                 // Directly obtain the cause and do a null check, so we only need one volatile read in case of a
                 // failure.
                 Throwable cause = future.cause();
                 if (cause != null) {
                     // Registration on the EventLoop failed so fail the Promise directly to not cause an
                     // IllegalStateException once we try to access the EventLoop of the Channel.
                     resolveAndConnectPromise.setFailure(cause);
                 } else {
                     Channel channel = future.getNow();
                     doResolveAndConnect0(channel, remoteAddress, localAddress, resolveAndConnectPromise);
                 }
             });
         }
         return resolveAndConnectPromise.asFuture();
     }
 
     private void doResolveAndConnect0(final Channel channel, SocketAddress remoteAddress,
                                       final SocketAddress localAddress, final Promise<Channel> promise) {
         try {
             final EventLoop eventLoop = channel.executor();
             final AddressResolver<SocketAddress> resolver = this.resolver.getResolver(eventLoop);
 
             if (!resolver.isSupported(remoteAddress) || resolver.isResolved(remoteAddress)) {
                 // Resolver has no idea about what to do with the specified remote address, or it's resolved already.
                 doConnect(remoteAddress, localAddress, channel, promise);
                 return;
             }
 
             final Future<SocketAddress> resolveFuture = resolver.resolve(remoteAddress);
 
             if (resolveFuture.isDone()) {
                 final Throwable resolveFailureCause = resolveFuture.cause();
 
                 if (resolveFailureCause != null) {
                     // Failed to resolve immediately
                     channel.close();
                     promise.setFailure(resolveFailureCause);
                 } else {
                     // Succeeded to resolve immediately; cached? (or did a blocking lookup)
                     doConnect(resolveFuture.getNow(), localAddress, channel, promise);
                     return;
                 }
             }
 
             // Wait until the name resolution is finished.
             resolveFuture.addListener(future -> {
                 if (future.cause() != null) {
                     channel.close();
                     promise.setFailure(future.cause());
                 } else {
                     doConnect(future.getNow(), localAddress, channel, promise);
                 }
             });
         } catch (Throwable cause) {
             promise.tryFailure(cause);
         }
     }
 
     private static void doConnect(
             SocketAddress remoteAddress, SocketAddress localAddress, Channel channel, Promise<Channel> promise) {
         // This method is invoked before channelRegistered() is triggered.  Give user handlers a chance to set up
         // the pipeline in its channelRegistered() implementation.
         channel.executor().execute(() -> {
             final Future<Void> future;
             if (localAddress == null) {
                 future = channel.connect(remoteAddress);
             } else {
                 future = channel.connect(remoteAddress, localAddress);
             }
             future.addListener(channel, ChannelFutureListeners.CLOSE_ON_FAILURE);
             future.map(v -> channel).cascadeTo(promise);
         });
     }
 
     @Override
     Future<Channel> init(Channel channel) {
         ChannelPipeline p = channel.pipeline();
 
         setChannelOptions(channel, newOptionsArray(), logger);
         setAttributes(channel, newAttributesArray());
 
         p.addLast(config.handler());
 
         return channel.executor().newSucceededFuture(channel);
     }
 
     @Override
     Channel newChannel(EventLoop eventLoop) throws Exception {
         return channelFactory.newChannel(eventLoop);
     }
 
     @Override
     public Bootstrap validate() {
         super.validate();
         if (config.handler() == null) {
             throw new IllegalStateException("handler not set");
         }
         if (config.channelFactory() == null) {
             throw new IllegalStateException("channelFactory not set");
         }
         return this;
     }
 
     @Override
     @SuppressWarnings("CloneDoesntCallSuperClone")
     public Bootstrap clone() {
         return new Bootstrap(this);
     }
 
     /**
      * Returns a deep clone of this bootstrap which has the identical configuration except that it uses
      * the given {@link EventLoopGroup}. This method is useful when making multiple {@link Channel}s with similar
      * settings.
      */
     public Bootstrap clone(EventLoopGroup group) {
         Bootstrap bs = new Bootstrap(this);
         bs.group = group;
         return bs;
     }
 
     @Override
     public final BootstrapConfig config() {
         return config;
     }
 
     final SocketAddress remoteAddress() {
         return remoteAddress;
     }
 
     final AddressResolverGroup<?> resolver() {
         return resolver;
     }
 }