/*
    * 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
    *
    *      https://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.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  package org.hipparchus.random;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  public class SynchronizedRandomGeneratorTest {
  
      @Test
      public void testAdapter() {
          final int seed = 12345;
          final RandomGenerator orig = new MersenneTwister(seed);
          final RandomGenerator wrap
              = new SynchronizedRandomGenerator(new MersenneTwister(seed));
  
          final int bSize = 67;
          final byte[] bOrig = new byte[bSize];
          final byte[] bWrap = new byte[bSize];
  
          for (int i = 0; i < 100; i++) {
              orig.nextBytes(bOrig);
              wrap.nextBytes(bWrap);
              for (int k = 0; k < bSize; k++) {
                  Assert.assertEquals(bOrig[k], bWrap[k]);
              }
  
              Assert.assertEquals(orig.nextInt(), wrap.nextInt());
  
              final int range = (i + 1) * 89;
              Assert.assertEquals(orig.nextInt(range), wrap.nextInt(range));
  
              Assert.assertEquals(orig.nextLong(), wrap.nextLong());
              Assert.assertEquals(orig.nextBoolean(), wrap.nextBoolean());
              Assert.assertEquals(orig.nextFloat(), wrap.nextFloat(), 0);
              Assert.assertEquals(orig.nextDouble(), wrap.nextDouble(), 0);
              Assert.assertEquals(orig.nextGaussian(), wrap.nextGaussian(), 0);
  
          }
      }
  
      @Test
      public void testMath899Sync() throws Throwable {
          try {
              final int numberOfThreads = 5;
              final int numberOfGenerators = 5;
              final int numberOfSamples = 100000;
              // Running the test several times in order to decrease the
              // probability that a non-thread-safe code did not trigger
              // a concurrency problem.
              for (int i = 0; i < 10; i++) {
                  doTestMath899(true, numberOfThreads, numberOfGenerators,
                                numberOfSamples);
              }
          } catch (InterruptedException e) {
              Assert.fail(e.getMessage());
          } catch (ExecutionException e) {
              throw e.getCause();
          }
      }
  
      /**
       * @param sync Whether to use a synchronizing wrapper.
       */
      private double[] doTestMath899(final boolean sync,
                                     final int numThreads,
                                     final int numGenerators,
                                     final int numSamples)
          throws InterruptedException,
                 ExecutionException {
          final RandomGenerator rng = new MersenneTwister();
          final RandomGenerator wrapper = sync ? new SynchronizedRandomGenerator(rng) : rng;
 
         final List<Callable<Double>> tasks = new ArrayList<Callable<Double>>();
         for (int i = 0; i < numGenerators; i++) {
             tasks.add(new Callable<Double>() {
                     @Override
                     public Double call() {
                         Double lastValue = 0d;
                         for (int j = 0; j < numSamples; j++) {
                             lastValue = wrapper.nextGaussian();
                         }
                         return lastValue;
                     }
                 });
         }
 
         final ExecutorService exec = Executors.newFixedThreadPool(numThreads);
         final List<Future<Double>> results = exec.invokeAll(tasks);
 
         final double[] values = new double[numGenerators];
         for (int i = 0; i < numGenerators; i++) {
             values[i] = results.get(i).get();
         }
         return values;
     }
 }