/*
    * 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:
    *
    *   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.netty.resolver;
  
  import io.netty.util.concurrent.EventExecutor;
  import io.netty.util.concurrent.Future;
  import io.netty.util.concurrent.FutureListener;
  import io.netty.util.concurrent.Promise;
  
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * A {@link AbstractAddressResolver} that resolves {@link InetSocketAddress}.
   */
  public class InetSocketAddressResolver extends AbstractAddressResolver<InetSocketAddress> {
  
      final NameResolver<InetAddress> nameResolver;
  
      /**
       * @param executor the {@link EventExecutor} which is used to notify the listeners of the {@link Future} returned
       *                 by {@link #resolve(java.net.SocketAddress)}
       * @param nameResolver the {@link NameResolver} used for name resolution
       */
      public InetSocketAddressResolver(EventExecutor executor, NameResolver<InetAddress> nameResolver) {
          super(executor, InetSocketAddress.class);
          this.nameResolver = nameResolver;
      }
  
      @Override
      protected boolean doIsResolved(InetSocketAddress address) {
          return !address.isUnresolved();
      }
  
      @Override
      protected void doResolve(final InetSocketAddress unresolvedAddress, final Promise<InetSocketAddress> promise)
              throws Exception {
          // Note that InetSocketAddress.getHostName() will never incur a reverse lookup here,
          // because an unresolved address always has a host name.
          nameResolver.resolve(unresolvedAddress.getHostName())
                  .addListener((FutureListener<InetAddress>) future -> {
                      if (future.isSuccess()) {
                          promise.setSuccess(new InetSocketAddress(future.getNow(), unresolvedAddress.getPort()));
                      } else {
                          promise.setFailure(future.cause());
                      }
                  });
      }
  
      @Override
      protected void doResolveAll(final InetSocketAddress unresolvedAddress,
                                  final Promise<List<InetSocketAddress>> promise) throws Exception {
          // Note that InetSocketAddress.getHostName() will never incur a reverse lookup here,
          // because an unresolved address always has a host name.
          nameResolver.resolveAll(unresolvedAddress.getHostName())
                  .addListener((FutureListener<List<InetAddress>>) future -> {
                      if (future.isSuccess()) {
                          List<InetAddress> inetAddresses = future.getNow();
                          List<InetSocketAddress> socketAddresses =
                                  new ArrayList<InetSocketAddress>(inetAddresses.size());
                          for (InetAddress inetAddress : inetAddresses) {
                              socketAddresses.add(new InetSocketAddress(inetAddress, unresolvedAddress.getPort()));
                          }
                          promise.setSuccess(socketAddresses);
                      } else {
                          promise.setFailure(future.cause());
                      }
                  });
      }
  
      @Override
      public void close() {
          nameResolver.close();
      }
  }