/*
    * 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 org.apache.commons.rng.simple;
  
  import java.io.IOException;
  import java.io.ObjectOutputStream;
  import java.io.ObjectInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.ByteArrayInputStream;
  import java.util.Random;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests for the {@link JDKRandomBridge} adaptor class.
   */
  class JDKRandomBridgeTest {
      @Test
      void testJDKRandomEquivalence() {
          // Initialize.
          final long seed = RandomSource.createLong();
          final Random rng1 = new Random(seed);
          final Random rng2 = new JDKRandomBridge(RandomSource.JDK, seed);
          checkSameSequence(rng1, rng2);
  
          // Reseed.
          final long newSeed = RandomSource.createLong();
          Assertions.assertNotEquals(seed, newSeed);
          rng1.setSeed(newSeed);
          rng2.setSeed(newSeed);
          checkSameSequence(rng1, rng2);
      }
  
      @Test
      void testSerialization()
          throws IOException,
                 ClassNotFoundException {
          // Initialize.
          final long seed = RandomSource.createLong();
          final Random rng = new JDKRandomBridge(RandomSource.SPLIT_MIX_64, seed);
  
          // Serialize.
          final ByteArrayOutputStream bos = new ByteArrayOutputStream();
          final ObjectOutputStream oos = new ObjectOutputStream(bos);
          oos.writeObject(rng);
  
          // Retrieve from serialized stream.
          final ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
          final ObjectInputStream ois = new ObjectInputStream(bis);
          final Random serialRng = (Random) (ois.readObject());
  
          // Check that the serialized data recreated the original state.
          checkSameSequence(rng, serialRng);
      }
  
      /**
       * Ensure that both generators produce the same sequences.
       *
       * @param rng1 RNG.
       * @param rng2 RNG.
       */
      private void checkSameSequence(Random rng1,
                                     Random rng2) {
          for (int i = 0; i < 4; i++) {
              Assertions.assertEquals(rng1.nextInt(),
                                      rng2.nextInt());
          }
          for (int i = 0; i < 7; i++) {
              Assertions.assertEquals(rng1.nextLong(),
                                      rng2.nextLong());
          }
          for (int i = 0; i < 9; i++) {
              Assertions.assertEquals(rng1.nextFloat(),
                                      rng2.nextFloat());
          }
          for (int i = 0; i < 12; i++) {
              Assertions.assertEquals(rng1.nextDouble(),
                                      rng2.nextDouble());
          }
          for (int i = 0; i < 17; i++) {
              Assertions.assertEquals(rng1.nextGaussian(),
                                      rng2.nextGaussian());
          }
          for (int i = 0; i < 18; i++) {
              Assertions.assertEquals(rng1.nextBoolean(),
                                     rng2.nextBoolean());
         }
         for (int i = 0; i < 19; i++) {
             final int max = i + 123456;
             Assertions.assertEquals(rng1.nextInt(max),
                                     rng2.nextInt(max));
         }
 
         final int len = 233;
         final byte[] store1 = new byte[len];
         final byte[] store2 = new byte[len];
         rng1.nextBytes(store1);
         rng2.nextBytes(store2);
         for (int i = 0; i < len; i++) {
             Assertions.assertEquals(store1[i],
                                     store2[i]);
         }
     }
 }