/*
    * 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.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInitializer;
  import io.netty.channel.SimpleChannelInboundHandler;
  import io.netty.handler.codec.http2.Http2FrameCodec;
  import io.netty.handler.codec.http2.Http2FrameCodecBuilder;
  import io.netty.handler.codec.http2.Http2MultiplexHandler;
  import io.netty.handler.codec.http2.Http2Settings;
  import io.netty.handler.ssl.SslContext;
  
  /**
   * Configures client pipeline to support HTTP/2 frames via {@link Http2FrameCodec} and {@link Http2MultiplexHandler}.
   */
  public final class Http2ClientFrameInitializer extends ChannelInitializer<Channel> {
  
      private final SslContext sslCtx;
  
      public Http2ClientFrameInitializer(SslContext sslCtx) {
          this.sslCtx = sslCtx;
      }
  
      @Override
      protected void initChannel(Channel ch) throws Exception {
          // ensure that our 'trust all' SSL handler is the first in the pipeline if SSL is enabled.
          if (sslCtx != null) {
              ch.pipeline().addFirst(sslCtx.newHandler(ch.alloc()));
          }
  
          final Http2FrameCodec http2FrameCodec = Http2FrameCodecBuilder.forClient()
              .initialSettings(Http2Settings.defaultSettings()) // this is the default, but shows it can be changed.
              .build();
          ch.pipeline().addLast(http2FrameCodec);
          ch.pipeline().addLast(new Http2MultiplexHandler(new SimpleChannelInboundHandler() {
              @Override
              protected void channelRead0(ChannelHandlerContext ctx, Object msg) {
                  // NOOP (this is the handler for 'inbound' streams, which is not relevant in this example)
              }
          }));
      }
  
  }