/*
    * Copyright 2023 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.http2;
  
  import io.netty.util.concurrent.Ticker;
  
  import static io.netty.util.internal.ObjectUtil.checkPositive;
  
  
  /**
   * Enforce a limit on the maximum number of RST frames that are allowed per a window
   * before the connection will be closed with a GO_AWAY frame.
   */
  final class Http2MaxRstFrameDecoder extends DecoratingHttp2ConnectionDecoder {
      private final int maxRstFramesPerWindow;
      private final int secondsPerWindow;
  
      Http2MaxRstFrameDecoder(Http2ConnectionDecoder delegate, int maxRstFramesPerWindow, int secondsPerWindow) {
          super(delegate);
          this.maxRstFramesPerWindow = checkPositive(maxRstFramesPerWindow, "maxRstFramesPerWindow");
          this.secondsPerWindow = checkPositive(secondsPerWindow, "secondsPerWindow");
      }
  
      @Override
      public void frameListener(Http2FrameListener listener) {
          if (listener != null) {
              super.frameListener(new Http2MaxRstFrameListener(
                      listener, maxRstFramesPerWindow, secondsPerWindow, Ticker.systemTicker()));
          } else {
              super.frameListener(null);
          }
      }
  
      @Override
      public Http2FrameListener frameListener() {
          Http2FrameListener frameListener = frameListener0();
          // Unwrap the original Http2FrameListener as we add this decoder under the hood.
          if (frameListener instanceof Http2MaxRstFrameListener) {
              return ((Http2MaxRstFrameListener) frameListener).listener;
          }
          return frameListener;
      }
  
      // Package-private for testing
      Http2FrameListener frameListener0() {
          return super.frameListener();
      }
  }