/*
    * 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.netty5.buffer.api.internal;
  
  import io.netty5.buffer.api.Drop;
  import io.netty5.buffer.api.Owned;
  import io.netty5.util.Resource;
  import io.netty5.util.Send;
  
  import java.lang.invoke.VarHandle;
  
  import static io.netty5.buffer.api.internal.Statics.findVarHandle;
  import static java.lang.invoke.MethodHandles.lookup;
  
  public class SendFromOwned<I extends Resource<I>, T extends ResourceSupport<I, T>> implements Send<I> {
      private static final VarHandle RECEIVED = findVarHandle(lookup(), SendFromOwned.class, "received", boolean.class);
      private final Owned<T> outgoing;
      private final Drop<T> drop;
      private final Class<?> concreteType;
      @SuppressWarnings("unused")
      private volatile boolean received; // Accessed via VarHandle
  
      public SendFromOwned(Owned<T> outgoing, Drop<T> drop, Class<?> concreteType) {
          this.outgoing = outgoing;
          this.drop = drop;
          this.concreteType = concreteType;
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public I receive() {
          gateReception();
          var copy = outgoing.transferOwnership(drop);
          drop.attach(copy);
          return (I) copy;
      }
  
      private void gateReception() {
          if ((boolean) RECEIVED.getAndSet(this, true)) {
              throw new IllegalStateException("This object has already been received.");
          }
      }
  
      @Override
      public boolean referentIsInstanceOf(Class<?> cls) {
          return cls.isAssignableFrom(concreteType);
      }
  
      @Override
      public void close() {
          if (!(boolean) RECEIVED.getAndSet(this, true)) {
              var copy = outgoing.transferOwnership(drop);
              drop.attach(copy);
              copy.close();
          }
      }
  }