/*
 * Copyright The OpenZipkin Authors
 * SPDX-License-Identifier: Apache-2.0
 */
package brave.internal;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/** Used to implement a context propagating executor service which wraps tasks */
public abstract class WrappingExecutorService implements ExecutorService {
  protected WrappingExecutorService() {
  }

  protected abstract ExecutorService delegate();

  protected abstract <R> Callable<R> wrap(Callable<R> task);

  protected abstract Runnable wrap(Runnable task);

  @Override
  public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().awaitTermination(timeout, unit);
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
    throws InterruptedException {
    return delegate().invokeAll(wrap(tasks));
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout,
    TimeUnit unit) throws InterruptedException {
    return delegate().invokeAll(wrap(tasks), timeout, unit);
  }

  @Override
  public <T> T invokeAny(Collection<? extends Callable<T>> tasks)
    throws InterruptedException, ExecutionException {
    return delegate().invokeAny(wrap(tasks));
  }

  @Override
  public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
    throws InterruptedException, ExecutionException, TimeoutException {
    return delegate().invokeAny(wrap(tasks), timeout, unit);
  }

  @Override
  public boolean isShutdown() {
    return delegate().isShutdown();
  }

  @Override
  public boolean isTerminated() {
    return delegate().isTerminated();
  }

  @Override
  public void shutdown() {
    delegate().shutdown();
  }

  @Override
  public List<Runnable> shutdownNow() {
    return delegate().shutdownNow();
  }

  @Override
  public void execute(Runnable task) {
    delegate().execute(wrap(task));
  }

  @Override
  public <T> Future<T> submit(Callable<T> task) {
    return delegate().submit(wrap(task));
  }

  @Override
  public Future<?> submit(Runnable task) {
    return delegate().submit(wrap(task));
  }

  @Override
  public <T> Future<T> submit(Runnable task, T result) {
    return delegate().submit(wrap(task), result);
  }

  <T> Collection<? extends Callable<T>> wrap(Collection<? extends Callable<T>> tasks) {
    ArrayList<Callable<T>> result = new ArrayList<Callable<T>>(tasks.size());
    for (Callable<T> task : tasks) {
      result.add(wrap(task));
    }
    return result;
  }
}
