/*
    * Copyright 2020 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.example.http2.helloworld.frame.client;
  
  import io.netty.bootstrap.Bootstrap;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelOption;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.channel.socket.nio.NioSocketChannel;
  import io.netty.handler.codec.http2.DefaultHttp2Headers;
  import io.netty.handler.codec.http2.DefaultHttp2HeadersFrame;
  import io.netty.handler.codec.http2.Http2HeadersFrame;
  import io.netty.handler.codec.http2.Http2SecurityUtil;
  import io.netty.handler.codec.http2.Http2StreamChannel;
  import io.netty.handler.codec.http2.Http2StreamChannelBootstrap;
  import io.netty.handler.ssl.ApplicationProtocolConfig;
  import io.netty.handler.ssl.ApplicationProtocolConfig.Protocol;
  import io.netty.handler.ssl.ApplicationProtocolConfig.SelectedListenerFailureBehavior;
  import io.netty.handler.ssl.ApplicationProtocolConfig.SelectorFailureBehavior;
  import io.netty.handler.ssl.ApplicationProtocolNames;
  import io.netty.handler.ssl.SslContext;
  import io.netty.handler.ssl.SslContextBuilder;
  import io.netty.handler.ssl.SslProvider;
  import io.netty.handler.ssl.SupportedCipherSuiteFilter;
  import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
  
  /**
   * An HTTP2 client that allows you to send HTTP2 frames to a server using the newer HTTP2
   * approach (via {@link io.netty.handler.codec.http2.Http2FrameCodec}).
   * When run from the command-line, sends a single HEADERS frame (with prior knowledge) to
   * the server configured at host:port/path.
   * You should include {@link io.netty.handler.codec.http2.Http2ClientUpgradeCodec} if the
   * HTTP/2 server you are hitting doesn't support h2c/prior knowledge.
   */
  public final class Http2FrameClient {
  
      static final boolean SSL = System.getProperty("ssl") != null;
      static final String HOST = System.getProperty("host", "127.0.0.1");
      static final int PORT = Integer.parseInt(System.getProperty("port", SSL? "8443" : "8080"));
      static final String PATH = System.getProperty("path", "/");
  
      private Http2FrameClient() {
      }
  
      public static void main(String[] args) throws Exception {
          final EventLoopGroup clientWorkerGroup = new NioEventLoopGroup();
  
          // Configure SSL.
          final SslContext sslCtx;
          if (SSL) {
              final SslProvider provider =
                      SslProvider.isAlpnSupported(SslProvider.OPENSSL)? SslProvider.OPENSSL : SslProvider.JDK;
              sslCtx = SslContextBuilder.forClient()
                    .sslProvider(provider)
                    .ciphers(Http2SecurityUtil.CIPHERS, SupportedCipherSuiteFilter.INSTANCE)
                    // you probably won't want to use this in production, but it is fine for this example:
                    .trustManager(InsecureTrustManagerFactory.INSTANCE)
                    .applicationProtocolConfig(new ApplicationProtocolConfig(
                            Protocol.ALPN,
                            SelectorFailureBehavior.NO_ADVERTISE,
                            SelectedListenerFailureBehavior.ACCEPT,
                            ApplicationProtocolNames.HTTP_2,
                            ApplicationProtocolNames.HTTP_1_1))
                    .build();
          } else {
              sslCtx = null;
          }
  
          try {
              final Bootstrap b = new Bootstrap();
              b.group(clientWorkerGroup);
              b.channel(NioSocketChannel.class);
              b.option(ChannelOption.SO_KEEPALIVE, true);
              b.remoteAddress(HOST, PORT);
              b.handler(new Http2ClientFrameInitializer(sslCtx));
  
              // Start the client.
              final Channel channel = b.connect().syncUninterruptibly().channel();
              System.out.println("Connected to [" + HOST + ':' + PORT + ']');
  
              final Http2ClientStreamFrameResponseHandler streamFrameResponseHandler =
                      new Http2ClientStreamFrameResponseHandler();
  
              final Http2StreamChannelBootstrap streamChannelBootstrap = new Http2StreamChannelBootstrap(channel);
              final Http2StreamChannel streamChannel = streamChannelBootstrap.open().syncUninterruptibly().getNow();
              streamChannel.pipeline().addLast(streamFrameResponseHandler);
 
             // Send request (a HTTP/2 HEADERS frame - with ':method = GET' in this case)
             final DefaultHttp2Headers headers = new DefaultHttp2Headers();
             headers.method("GET");
             headers.path(PATH);
             headers.scheme(SSL? "https" : "http");
             final Http2HeadersFrame headersFrame = new DefaultHttp2HeadersFrame(headers, true);
             streamChannel.writeAndFlush(headersFrame);
             System.out.println("Sent HTTP/2 GET request to " + PATH);
 
             // Wait for the responses (or for the latch to expire), then clean up the connections
             if (!streamFrameResponseHandler.responseSuccessfullyCompleted()) {
                 System.err.println("Did not get HTTP/2 response in expected time.");
             }
 
             System.out.println("Finished HTTP/2 request, will close the connection.");
 
             // Wait until the connection is closed.
             channel.close().syncUninterruptibly();
         } finally {
             clientWorkerGroup.shutdownGracefully();
         }
     }
 
 }