/*
    * Copyright 2021 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.handler.codec.http3;
  
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.handler.codec.http3.Http3RequestStreamEncodeStateValidator.State;
  
  import static io.netty.handler.codec.http3.Http3FrameValidationUtils.frameTypeUnexpected;
  import static io.netty.handler.codec.http3.Http3RequestStreamEncodeStateValidator.evaluateFrame;
  import static io.netty.handler.codec.http3.Http3RequestStreamEncodeStateValidator.isFinalHeadersReceived;
  import static io.netty.handler.codec.http3.Http3RequestStreamEncodeStateValidator.isStreamStarted;
  import static io.netty.handler.codec.http3.Http3RequestStreamEncodeStateValidator.isTrailersReceived;
  
  final class Http3RequestStreamDecodeStateValidator extends ChannelInboundHandlerAdapter
          implements Http3RequestStreamCodecState {
      private State state = State.None;
  
      @Override
      public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
          if (!(msg instanceof Http3RequestStreamFrame)) {
              super.channelRead(ctx, msg);
              return;
          }
          final Http3RequestStreamFrame frame = (Http3RequestStreamFrame) msg;
          final State nextState = evaluateFrame(state, frame);
          if (nextState == null) {
              frameTypeUnexpected(ctx, msg);
              return;
          }
          state = nextState;
          super.channelRead(ctx, msg);
      }
  
      @Override
      public boolean started() {
          return isStreamStarted(state);
      }
  
      @Override
      public boolean receivedFinalHeaders() {
          return isFinalHeadersReceived(state);
      }
  
      @Override
      public boolean terminated() {
          return isTrailersReceived(state);
      }
  }