/*
    * 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.math4.legacy.genetics;
  
  import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
  import org.apache.commons.math4.legacy.exception.MathIllegalArgumentException;
  import org.junit.Assert;
  import org.junit.Test;
  
  public class CycleCrossoverTest {
  
      @Test
      public void testCrossoverExample() {
          // taken from http://www.rubicite.com/Tutorials/GeneticAlgorithms/CrossoverOperators/CycleCrossoverOperator.aspx
          final Integer[] p1 = new Integer[] { 8, 4, 7, 3, 6, 2, 5, 1, 9, 0 };
          final Integer[] p2 = new Integer[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
          final DummyListChromosome p1c = new DummyListChromosome(p1);
          final DummyListChromosome p2c = new DummyListChromosome(p2);
  
          final CrossoverPolicy cp = new CycleCrossover<>();
          final ChromosomePair pair = cp.crossover(p1c, p2c);
  
          final Integer[] c1 = ((DummyListChromosome) pair.getFirst()).getRepresentation().toArray(new Integer[p1.length]);
          final Integer[] c2 = ((DummyListChromosome) pair.getSecond()).getRepresentation().toArray(new Integer[p2.length]);
  
          final Integer[] c1e = new Integer[] { 8, 1, 2, 3, 4, 5, 6, 7, 9, 0 };
          final Integer[] c2e = new Integer[] { 0, 4, 7, 3, 6, 2, 5, 1, 8, 9 };
  
          Assert.assertArrayEquals(c1e, c1);
          Assert.assertArrayEquals(c2e, c2);
      }
  
      @Test
      public void testCrossoverExample2() {
          // taken from http://www.scribd.com/doc/54206412/32/Cycle-crossover
          final Integer[] p1 = new Integer[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
          final Integer[] p2 = new Integer[] { 9, 3, 7, 8, 2, 6, 5, 1, 4};
          final DummyListChromosome p1c = new DummyListChromosome(p1);
          final DummyListChromosome p2c = new DummyListChromosome(p2);
  
          final CrossoverPolicy cp = new CycleCrossover<>();
          final ChromosomePair pair = cp.crossover(p1c, p2c);
  
          final Integer[] c1 = ((DummyListChromosome) pair.getFirst()).getRepresentation().toArray(new Integer[p1.length]);
          final Integer[] c2 = ((DummyListChromosome) pair.getSecond()).getRepresentation().toArray(new Integer[p2.length]);
  
          final Integer[] c1e = new Integer[] { 1, 3, 7, 4, 2, 6, 5, 8, 9 };
          final Integer[] c2e = new Integer[] { 9, 2, 3, 8, 5, 6, 7, 1, 4 };
  
          Assert.assertArrayEquals(c1e, c1);
          Assert.assertArrayEquals(c2e, c2);
      }
  
      @Test
      public void testCrossover() {
          final Integer[] p1 = new Integer[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
          final Integer[] p2 = new Integer[] { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
          final DummyListChromosome p1c = new DummyListChromosome(p1);
          final DummyListChromosome p2c = new DummyListChromosome(p2);
  
          final CrossoverPolicy cp = new CycleCrossover<Integer>(true);
  
          for (int i = 0; i < 20; i++) {
              final ChromosomePair pair = cp.crossover(p1c, p2c);
  
              final Integer[] c1 = ((DummyListChromosome) pair.getFirst()).getRepresentation().toArray(new Integer[p1.length]);
              final Integer[] c2 = ((DummyListChromosome) pair.getSecond()).getRepresentation().toArray(new Integer[p2.length]);
  
              int index = 0;
              // Determine if it is in the same spot as in the first parent, if
              // not it comes from the second parent.
              for (final Integer j : c1) {
                  if (!p1[index].equals(j)) {
                      Assert.assertEquals(j, p2[index]);
                  } else {
                      Assert.assertEquals(j, p1[index]);
                  }
                  index++;
              }
  
              // Same as above only for the second parent.
              index = 0;
              for (final Integer k : c2) {
                  if (p2[index] != k) {
                      Assert.assertEquals(k, p1[index]);
                 } else {
                     Assert.assertEquals(k, p2[index]);
                 }
                 index++;
             }
         }
     }
 
     @Test(expected = DimensionMismatchException.class)
     public void testCrossoverDimensionMismatchException() {
         final Integer[] p1 = new Integer[] { 1, 0, 1, 0, 0, 1, 0, 1, 1 };
         final Integer[] p2 = new Integer[] { 0, 1, 1, 0, 1 };
 
         final BinaryChromosome p1c = new DummyBinaryChromosome(p1);
         final BinaryChromosome p2c = new DummyBinaryChromosome(p2);
 
         final CrossoverPolicy cp = new CycleCrossover<>();
         cp.crossover(p1c, p2c);
     }
 
     @Test(expected = MathIllegalArgumentException.class)
     public void testCrossoverInvalidFixedLengthChromosomeFirst() {
         final Integer[] p1 = new Integer[] { 1, 0, 1, 0, 0, 1, 0, 1, 1 };
         final BinaryChromosome p1c = new DummyBinaryChromosome(p1);
         final Chromosome p2c = new Chromosome() {
             @Override
             public double fitness() {
                 // Not important
                 return 0;
             }
         };
 
         final CrossoverPolicy cp = new CycleCrossover<>();
         cp.crossover(p1c, p2c);
     }
 
     @Test(expected = MathIllegalArgumentException.class)
     public void testCrossoverInvalidFixedLengthChromosomeSecond() {
         final Integer[] p1 = new Integer[] { 1, 0, 1, 0, 0, 1, 0, 1, 1 };
         final BinaryChromosome p2c = new DummyBinaryChromosome(p1);
         final Chromosome p1c = new Chromosome() {
             @Override
             public double fitness() {
                 // Not important
                 return 0;
             }
         };
 
         final CrossoverPolicy cp = new CycleCrossover<>();
         cp.crossover(p1c, p2c);
     }
 }