/*
    * Copyright 2025 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.compression;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.util.internal.ObjectUtil;
  
  /**
   * Most decompressor implementations play fast and loose with {@link Decompressor} API contracts. This wrapper makes
   * sure callers follow that contract.
   */
  final class DefensiveDecompressor implements Decompressor {
      private final Decompressor delegate;
      private Status status;
      private boolean closed;
      private boolean failed;
  
      DefensiveDecompressor(Decompressor delegate) {
          this.delegate = ObjectUtil.checkNotNull(delegate, "delegate");
      }
  
      @Override
      public Status status() throws DecompressionException {
          checkReady();
          try {
              status = delegate.status();
          } catch (Exception e) {
              failed = true;
              throw e;
          }
          return status;
      }
  
      @Override
      public void addInput(ByteBuf buf) throws DecompressionException {
          try {
              checkReady();
              checkState(Status.NEED_INPUT);
          } catch (Throwable t) {
              buf.release();
              throw t;
          }
          try {
              delegate.addInput(buf);
          } catch (Exception e) {
              failed = true;
              throw e;
          }
          status = null;
      }
  
      @Override
      public void endOfInput() throws DecompressionException {
          checkReady();
          checkState(Status.NEED_INPUT);
          try {
              delegate.endOfInput();
          } catch (Exception e) {
              failed = true;
              throw e;
          }
          status = null;
      }
  
      @Override
      public ByteBuf takeOutput() throws DecompressionException {
          checkReady();
          checkState(Status.NEED_OUTPUT);
          ByteBuf out;
          try {
              out = delegate.takeOutput();
          } catch (Exception e) {
              failed = true;
              throw e;
          }
          status = null;
          return out;
      }
  
      @Override
      public void close() {
          closed = true;
          delegate.close();
      }
  
      private void checkReady() {
         if (closed) {
             throw new IllegalStateException("Already closed");
         }
         if (failed) {
             throw new IllegalStateException("Previous call failed");
         }
     }
 
     private void checkState(Status expected) {
         if (this.status != expected) {
             throw new IllegalStateException("Not in expected state " + expected + ", was " + this.status);
         }
     }
 }