/*
 * Copyright 2015 LinkedIn, Inc
 *
 * 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 com.linkedin.parseq;

import static com.linkedin.parseq.function.Tuples.tuple;

import com.linkedin.parseq.function.Tuple2;
import com.linkedin.parseq.internal.InternalUtil;
import com.linkedin.parseq.promise.Promise;
import com.linkedin.parseq.promise.Promises;
import com.linkedin.parseq.promise.SettablePromise;

public class Par2Task<T1, T2> extends BaseTask<Tuple2<T1, T2>> implements Tuple2Task<T1, T2> {
  private final Tuple2<Task<T1>, Task<T2>> _tasks;

  public Par2Task(final String name, Task<T1> task1, Task<T2> task2) {
    super(name);
    _tasks = tuple(task1, task2);
  }

  @Override
  protected Promise<Tuple2<T1, T2>> run(final Context context) throws Exception {
    final SettablePromise<Tuple2<T1, T2>> result = Promises.settable();

    InternalUtil.fastFailAfter(p -> {
      if (p.isFailed()) {
        result.fail(p.getError());
      } else {
        result.done(tuple(_tasks._1().get(),
                          _tasks._2().get()));
      }
    },
    _tasks._1(),
    _tasks._2());

    _tasks.forEach(t -> context.run((Task<?>)t));

    return result;
  }

}
