/*
 * Copyright 2016, gRPC Authors All rights reserved.
 *
 * Licensed 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.grpc.netty;

import io.grpc.Status;
import io.grpc.internal.ManagedClientTransport;

/** Maintainer of transport lifecycle status. */
final class ClientTransportLifecycleManager {
  private final ManagedClientTransport.Listener listener;
  private boolean transportReady;
  private boolean transportShutdown;
  private boolean transportInUse;
  /** null iff !transportShutdown. */
  private Status shutdownStatus;
  /** null iff !transportShutdown. */
  private Throwable shutdownThrowable;
  private boolean transportTerminated;

  public ClientTransportLifecycleManager(ManagedClientTransport.Listener listener) {
    this.listener = listener;
  }

  public void notifyReady() {
    if (transportReady || transportShutdown) {
      return;
    }
    transportReady = true;
    listener.transportReady();
  }

  public void notifyShutdown(Status s) {
    if (transportShutdown) {
      return;
    }
    transportShutdown = true;
    shutdownStatus = s;
    shutdownThrowable = s.asException();
    listener.transportShutdown(s);
  }

  public void notifyInUse(boolean inUse) {
    if (inUse == transportInUse) {
      return;
    }
    transportInUse = inUse;
    listener.transportInUse(inUse);
  }

  public void notifyTerminated(Status s) {
    if (transportTerminated) {
      return;
    }
    transportTerminated = true;
    notifyShutdown(s);
    listener.transportTerminated();
  }

  public Status getShutdownStatus() {
    return shutdownStatus;
  }

  public Throwable getShutdownThrowable() {
    return shutdownThrowable;
  }
}
