/*
 * ToroDB
 * Copyright © 2014 8Kdata Technology (www.8kdata.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.torodb.concurrent;

import com.torodb.core.annotations.ParallelLevel;
import com.torodb.core.concurrent.ConcurrentToolsFactory;
import com.torodb.core.concurrent.StreamExecutor;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

import javax.inject.Inject;

/**
 *
 */
public class DefaultConcurrentToolsFactory implements ConcurrentToolsFactory {

  private final BlockerThreadFactoryFunction blockerThreadFactoryFunction;
  private final ForkJoinThreadFactoryFunction forkJoinThreadFactoryFunction;
  private final int defaultThreads;
  private final ExecutorServiceShutdownHelper shutdownHelper;

  @Inject
  public DefaultConcurrentToolsFactory(BlockerThreadFactoryFunction blockerThreadFactoryFunction,
      ForkJoinThreadFactoryFunction forkJoinThreadFactoryFunction,
      @ParallelLevel int parallelLevel, ExecutorServiceShutdownHelper shutdownHelper) {
    this.blockerThreadFactoryFunction = blockerThreadFactoryFunction;
    this.forkJoinThreadFactoryFunction = forkJoinThreadFactoryFunction;
    this.defaultThreads = parallelLevel;
    this.shutdownHelper = shutdownHelper;
  }

  @Override
  public int getDefaultMaxThreads() {
    return defaultThreads;
  }

  @Override
  public StreamExecutor createStreamExecutor(String prefix,
      boolean blockerTasks, int maxThreads) {
    return new AkkaStreamExecutor(
        blockerThreadFactoryFunction.apply(prefix),
        maxThreads,
        createExecutorService(prefix, blockerTasks, maxThreads),
        prefix
    );
  }

  @Override
  public ScheduledExecutorService createScheduledExecutorServiceWithMaxThreads(
      String prefix, int maxThreads) {
    ThreadFactory threadFactory = blockerThreadFactoryFunction.apply(prefix);
    ScheduledThreadPoolExecutor executorService =
        new ScheduledThreadPoolExecutor(maxThreads, threadFactory);
    shutdownHelper.terminateOnShutdown(prefix, executorService);

    return executorService;
  }

  @Override
  public ExecutorService createExecutorServiceWithMaxThreads(
      String prefix, int maxThreads) {
    ThreadFactory threadFactory = blockerThreadFactoryFunction.apply(prefix);
    ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
        maxThreads, maxThreads,
        10L, TimeUnit.MINUTES,
        new LinkedBlockingQueue<>(),
        threadFactory);
    threadPoolExecutor.allowCoreThreadTimeOut(true);
    shutdownHelper.terminateOnShutdown(prefix, threadPoolExecutor);
    return threadPoolExecutor;
  }

  @Override
  @SuppressFBWarnings(value = {"NP_NONNULL_PARAM_VIOLATION"},
      justification = "ForkJoinPool constructor admits a null "
      + "UncaughtExceptionHandler")
  public ExecutorService createExecutorService(String prefix,
      boolean blockerTasks, int maxThreads) {
    ExecutorService executorService;
    if (blockerTasks) {
      ThreadFactory threadFactory =
          blockerThreadFactoryFunction.apply(prefix);
      ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
          maxThreads, maxThreads,
          10L, TimeUnit.MINUTES,
          new LinkedBlockingQueue<>(),
          threadFactory);
      threadPoolExecutor.allowCoreThreadTimeOut(true);
      executorService = threadPoolExecutor;
    } else {
      ForkJoinWorkerThreadFactory threadFactory =
          forkJoinThreadFactoryFunction.apply(prefix);
      executorService = new ForkJoinPool(maxThreads, threadFactory,
          null, true);
    }
    shutdownHelper.terminateOnShutdown(prefix, executorService);
    return executorService;
  }

  public static interface BlockerThreadFactoryFunction extends
      Function<String, ThreadFactory> {

  }

  public static interface ForkJoinThreadFactoryFunction extends
      Function<String, ForkJoinWorkerThreadFactory> {

  }

}