content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF 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
   *
   *     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 accord.maelstrom;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.PriorityQueue;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.function.Supplier;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import accord.local.Node.Id;
  import accord.maelstrom.Cluster.Queue;
  import accord.maelstrom.Cluster.QueueSupplier;
  import accord.utils.DefaultRandom;
  import accord.utils.RandomSource;
  
  import static accord.utils.Utils.toArray;
  
  public class Runner
  {
      private static final Logger logger = LoggerFactory.getLogger(Runner.class);
  
      static class StandardQueue<T> implements Queue<T>
      {
          static class Factory implements QueueSupplier
          {
              final RandomSource seeds;
  
              Factory(RandomSource seeds)
              {
                  this.seeds = seeds;
              }
  
              @Override
              public <T> Queue<T> get()
              {
                  return new StandardQueue<>(seeds.fork());
              }
          }
  
          static class Item<T> implements Comparable<Item<T>>
          {
              final long time;
              final int seq;
              final T item;
  
              Item(long time, int seq, T item)
              {
                  this.time = time;
                  this.seq = seq;
                  this.item = item;
              }
  
              @Override
              public int compareTo(Item<T> that)
              {
                  int c = Long.compare(this.time, that.time);
                  if (c == 0) c = Integer.compare(this.seq, that.seq);
                  return c;
              }
          }
  
          final PriorityQueue<Item<T>> queue = new PriorityQueue<>();
          final RandomSource random;
          long now;
          int seq;
  
          StandardQueue(RandomSource random)
          {
              this.random = random;
          }
  
          @Override
          public synchronized void add(T item)
          {
              add(item, random.nextInt(500), TimeUnit.MILLISECONDS);
          }
  
          @Override
          public synchronized void add(T item, long delay, TimeUnit units)
          {
              queue.add(new Item<>(now + units.toMillis(delay), seq++, item));
          }
  
          @Override
          public synchronized T poll()
          {
              Item<T> item = queue.poll();
              if (item == null)
                  return null;
              now = item.time;
              return item.item;
          }
  
          @Override
          public synchronized int size()
          {
              return queue.size();
          }
      }
  
      static void run(int nodeCount, QueueSupplier queueSupplier, Supplier<RandomSource> randomSupplier, TopologyFactory factory, String ... commands) throws IOException
      {
          run(nodeCount, queueSupplier, randomSupplier, factory, new Supplier<Packet>()
          {
              int i = 0;
              @Override
              public Packet get()
              {
                  return i == commands.length ? null : Packet.parse(commands[i++]);
              }
          });
      }
  
      static void run(int nodeCount, QueueSupplier queueSupplier, Supplier<RandomSource> randomSupplier, TopologyFactory factory, Supplier<Packet> commands) throws IOException
      {
          List<Id> nodes = new ArrayList<>();
          for (int i = 1 ; i <= nodeCount ; ++i)
              nodes.add(new Id(i));
  
          Cluster.run(toArray(nodes, Id[]::new), queueSupplier, ignore -> {}, randomSupplier, () -> new AtomicLong()::incrementAndGet, factory, commands, System.err);
      }
  
      public static Builder test()
      {
          return new Builder(Thread.currentThread().getStackTrace()[2].getMethodName());
      }
  
      public static class Builder
      {
          public static final String ACCORD_TEST_SEED = "accord.test.%s.seed";
  
          private final String key;
          private long seed;
          private int nodeCount = 3;
          private TopologyFactory factory = new TopologyFactory(4, 3);
  
          private Builder(String name)
          {
              key = String.format(ACCORD_TEST_SEED, name);
              String userSeed = System.getProperty(key, null);
              seed = userSeed != null ? Long.parseLong(userSeed) : System.nanoTime();
          }
  
          Builder seed(long seed)
          {
              this.seed = seed;
              return this;
          }
  
          Builder nodeCount(int nodeCount)
          {
              this.nodeCount = nodeCount;
              return this;
          }
  
          Builder factory(TopologyFactory factory)
          {
              this.factory = factory;
              return this;
          }
  
          void run(String ... commands) throws IOException
          {
              logger.info("Seed {}; rerun with -D{}={}", seed, key, seed);
              RandomSource randomSource = new DefaultRandom(seed);
              try
              {
                  Runner.run(nodeCount, new StandardQueue.Factory(randomSource), randomSource::fork, factory, commands);
              }
              catch (Throwable t)
              {
                  throw new AssertionError("Failure for seed " + seed, t);
              }
          }
      }
  }
  