/*
    * 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.collections4.iterators;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertSame;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Comparator;
  import java.util.List;
  
  import org.apache.commons.collections4.comparators.ComparableComparator;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Unit test suite for {@link CollatingIterator}.
   */
  @SuppressWarnings("boxing")
  public class CollatingIteratorTest extends AbstractIteratorTest<Integer> {
  
      private Comparator<Integer> comparator;
  
      private ArrayList<Integer> evens;
      private ArrayList<Integer> odds;
      private ArrayList<Integer> fib;
  
      @Override
      public CollatingIterator<Integer> makeEmptyIterator() {
          return new CollatingIterator<>(comparator);
      }
  
      @Override
      public CollatingIterator<Integer> makeObject() {
          final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
          iter.addIterator(evens.iterator());
          iter.addIterator(odds.iterator());
          iter.addIterator(fib.iterator());
          return iter;
      }
  
      @BeforeEach
      public void setUp() throws Exception {
          comparator = new ComparableComparator<>();
          evens = new ArrayList<>();
          odds = new ArrayList<>();
          for (int i = 0; i < 20; i++) {
              if (0 == i % 2) {
                  evens.add(i);
              } else {
                  odds.add(i);
              }
          }
          fib = new ArrayList<>();
          fib.add(1);
          fib.add(1);
          fib.add(2);
          fib.add(3);
          fib.add(5);
          fib.add(8);
          fib.add(13);
          fib.add(21);
      }
  
      @Test
      public void testGetSetComparator() {
          final CollatingIterator<Integer> iter = new CollatingIterator<>();
          assertNull(iter.getComparator());
          iter.setComparator(comparator);
          assertSame(comparator, iter.getComparator());
          iter.setComparator(null);
          assertNull(iter.getComparator());
      }
  
      @Test
      public void testIterateEven() {
          final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
          iter.addIterator(evens.iterator());
          for (final Integer even : evens) {
              assertTrue(iter.hasNext());
             assertEquals(even, iter.next());
             assertEquals(0, iter.getIteratorIndex());
         }
         assertFalse(iter.hasNext());
     }
 
     @Test
     public void testIterateEvenEven() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
         iter.addIterator(evens.iterator());
         iter.addIterator(evens.iterator());
         for (final Integer even : evens) {
             assertTrue(iter.hasNext());
             assertEquals(even, iter.next());
             assertEquals(0, iter.getIteratorIndex());
             assertTrue(iter.hasNext());
             assertEquals(even, iter.next());
             assertEquals(1, iter.getIteratorIndex());
         }
         assertFalse(iter.hasNext());
     }
 
     @Test
     public void testIterateEvenOdd() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator, evens.iterator(), odds.iterator());
         for (int i = 0; i < 20; i++) {
             assertTrue(iter.hasNext());
             assertEquals(Integer.valueOf(i), iter.next());
             assertEquals(i % 2, iter.getIteratorIndex());
         }
         assertFalse(iter.hasNext());
     }
 
     @Test
     public void testIterateFibEvenOdd() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
         iter.addIterator(fib.iterator());
         iter.addIterator(evens.iterator());
         iter.addIterator(odds.iterator());
 
         assertEquals(Integer.valueOf(0), iter.next());  // even   0
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(1), iter.next());  // fib    1
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(1), iter.next());  // fib    1
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(1), iter.next());  // odd    1
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(2), iter.next());  // fib    2
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(2), iter.next());  // even   2
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(3), iter.next());  // fib    3
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(3), iter.next());  // odd    3
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(4), iter.next());  // even   4
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(5), iter.next());  // fib    5
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(5), iter.next());  // odd    5
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(6), iter.next());  // even   6
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(7), iter.next());  // odd    7
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(8), iter.next());  // fib    8
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(8), iter.next());  // even   8
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(9), iter.next());  // odd    9
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(10), iter.next()); // even  10
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(11), iter.next()); // odd   11
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(12), iter.next()); // even  12
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(13), iter.next()); // fib   13
         assertEquals(0, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(13), iter.next()); // odd   13
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(14), iter.next()); // even  14
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(15), iter.next()); // odd   15
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(16), iter.next()); // even  16
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(17), iter.next()); // odd   17
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(18), iter.next()); // even  18
         assertEquals(1, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(19), iter.next()); // odd   19
         assertEquals(2, iter.getIteratorIndex());
         assertEquals(Integer.valueOf(21), iter.next()); // fib   21
         assertEquals(0, iter.getIteratorIndex());
 
         assertFalse(iter.hasNext());
     }
 
     @Test
     public void testIterateOddEven() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator, odds.iterator(), evens.iterator());
         for (int i = 0; i < 20; i++) {
             assertTrue(iter.hasNext());
             assertEquals(Integer.valueOf(i), iter.next());
             assertEquals(i % 2 == 0 ? 1 : 0, iter.getIteratorIndex());
         }
         assertFalse(iter.hasNext());
     }
 
     @Test
     public void testNullComparator() {
         final List<Integer> l1 = Arrays.asList(1, 3, 5);
         final List<Integer> l2 = Arrays.asList(2, 4, 6);
 
         final CollatingIterator<Integer> collatingIterator1 = new CollatingIterator<>(null, l1.iterator(), l2.iterator());
         assertThrows(NullPointerException.class, collatingIterator1::next, "You must invoke setComparator");
 
         int i = 0;
         final CollatingIterator<Integer> collatingIterator2 = new CollatingIterator<>(null, l1.iterator(), l2.iterator());
         collatingIterator2.setComparator(new ComparableComparator<>());
         for (; collatingIterator2.hasNext(); i++) {
             final Integer n = collatingIterator2.next();
             assertEquals((int) n, i + 1, "wrong order");
         }
         assertEquals(i, l1.size() + l2.size(), "wrong size");
     }
 
     @Test
     public void testRemoveFromDouble() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
         iter.addIterator(evens.iterator());
         iter.addIterator(odds.iterator());
         int expectedSize = evens.size() + odds.size();
         while (iter.hasNext()) {
             final Object o = iter.next();
             final Integer val = (Integer) o;
             if (val.intValue() % 4 == 0 || val.intValue() % 3 == 0) {
                 expectedSize--;
                 iter.remove();
             }
         }
         assertEquals(expectedSize, evens.size() + odds.size());
     }
 
     @Test
     public void testRemoveFromSingle() {
         final CollatingIterator<Integer> iter = new CollatingIterator<>(comparator);
         iter.addIterator(evens.iterator());
         int expectedSize = evens.size();
         while (iter.hasNext()) {
             final Object o = iter.next();
             final Integer val = (Integer) o;
             if (val.intValue() % 4 == 0) {
                 expectedSize--;
                 iter.remove();
             }
         }
         assertEquals(expectedSize, evens.size());
     }
 }