content: /*
   * Copyright 2021-2024 Aklivity Inc.
   *
   * Aklivity 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:
   *
   *   http://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.aklivity.zilla.runtime.engine.test.internal.k3po.ext.behavior.handler;
  
  import static java.util.Objects.requireNonNull;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import org.jboss.netty.buffer.ChannelBuffer;
  import org.jboss.netty.channel.Channel;
  
  import io.aklivity.k3po.runtime.driver.internal.behavior.handler.codec.ChannelDecoder;
  import io.aklivity.k3po.runtime.driver.internal.behavior.handler.codec.MessageDecoder;
  import io.aklivity.k3po.runtime.lang.types.StructuredTypeInfo;
  import io.aklivity.zilla.runtime.engine.test.internal.k3po.ext.behavior.ZillaChannel;
  import io.aklivity.zilla.runtime.engine.test.internal.k3po.ext.behavior.ZillaExtensionKind;
  
  public final class ZillaExtensionDecoder implements ChannelDecoder
  {
      private final ZillaExtensionKind readExtKind;
      private final StructuredTypeInfo type;
      private final List<MessageDecoder> decoders;
      private final List<MessageDecoder> remainingDecoders;
  
      public ZillaExtensionDecoder(
          ZillaExtensionKind readExtKind,
          StructuredTypeInfo type,
          List<MessageDecoder> decoders)
      {
          this.readExtKind = readExtKind;
          this.type = type;
          this.decoders = requireNonNull(decoders);
          this.remainingDecoders = new ArrayList<>(decoders);
      }
  
      @Override
      public boolean decode(
          Channel channel) throws Exception
      {
          return decode((ZillaChannel) channel);
      }
  
      @Override
      public String toString()
      {
          StringBuilder sb = new StringBuilder();
          sb.append(type.getQualifiedName()).append(' ');
          for (MessageDecoder decoder : decoders)
          {
              sb.append(decoder).append(' ');
          }
          sb.setLength(sb.length() - 1);
          return sb.toString();
      }
  
      private boolean decode(
          ZillaChannel channel) throws Exception
      {
          final ChannelBuffer readExtBuffer = readExtKind.decodeBuffer(channel);
  
          Iterator<MessageDecoder> iterator = remainingDecoders.iterator();
  
          while (iterator.hasNext())
          {
              MessageDecoder decoder = iterator.next();
  
              ChannelBuffer remainingExtBuffer;
  
              if (iterator.hasNext())
              {
                  remainingExtBuffer = decoder.decode(readExtBuffer);
              }
              else
              {
                  remainingExtBuffer = decoder.decodeLast(readExtBuffer);
              }
  
              if (remainingExtBuffer == null)
              {
                  return false;
              }
  
              // rewind as needed
              final int remainingExtBytes = remainingExtBuffer.readableBytes();
              if (remainingExtBytes > 0)
              {
                  readExtBuffer.skipBytes(-remainingExtBytes);
              }
              // Remove the decoder because it is done
              iterator.remove();
          }
  
          return true;
      }
  }
  