/*
    * 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.assertThrows;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Iterator;
  import java.util.List;
  import java.util.function.Function;
  import java.util.function.Predicate;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  public class ExtendedIteratorTest {
      /**
       * Collection of {@link Integer}s
       */
      private List<Integer> collectionA;
  
      @BeforeEach
      public void setUp() {
          collectionA = new ArrayList<>();
          collectionA.add(1);
          collectionA.add(2);
          collectionA.add(3);
          collectionA.add(4);
          collectionA.add(5);
          collectionA.add(6);
      }
  
      @Test
      public void testAddTo() {
          final List<Integer> expected = new ArrayList<>(collectionA);
          expected.addAll(collectionA);
          final List<Integer> actual = ExtendedIterator.create(collectionA.iterator()).addTo(new ArrayList<>(collectionA));
          assertEquals(expected, actual);
      }
  
      @Test
      public void testAndThen() {
          final Iterator<Integer> iter1 = Arrays.asList(1, 2, 3).iterator();
          final Iterator<Integer> iter2 = Arrays.asList(4, 5, 6).iterator();
  
          final ExtendedIterator<Integer> underTest = ExtendedIterator.create(iter1).andThen(iter2);
          final List<Integer> actual = new ArrayList<>();
          underTest.forEachRemaining(actual::add);
          assertEquals(collectionA, actual);
      }
  
      @Test
      public void testCreate() {
          final Iterator<Integer> iter = ExtendedIterator.create(collectionA.iterator());
          final List<Integer> actual = new ArrayList<>();
          iter.forEachRemaining(actual::add);
          assertEquals(collectionA, actual);
      }
  
      @Test
      public void testCreateNoRemove() {
          final Iterator<Integer> iter = ExtendedIterator.createNoRemove(collectionA.iterator());
          assertThrows(UnsupportedOperationException.class, iter::remove);
      }
  
      @Test
      public void testCreateWithStream() {
          final Iterator<Integer> iter = ExtendedIterator.create(collectionA.stream());
          assertThrows(UnsupportedOperationException.class, iter::remove);
          final List<Integer> actual = new ArrayList<>();
          iter.forEachRemaining(actual::add);
          assertEquals(collectionA, actual);
      }
  
      @Test
      public void testEmptyIterator() {
          assertFalse(ExtendedIterator.emptyIterator().hasNext());
      }
  
      @Test
      public void testFilter() {
         final List<Integer> expected = Arrays.asList(2, 4, 6);
         final Predicate<Integer> predicate = i -> i % 2 == 0;
         final ExtendedIterator<Integer> underTest = ExtendedIterator.create(collectionA.iterator()).filter(predicate);
         final List<Integer> actual = new ArrayList<>();
         underTest.forEachRemaining(actual::add);
         assertEquals(expected, actual);
     }
 
     @Test
     public void testFlatten() {
         final Iterator<Iterator<Integer>> iteratorIterator = Arrays.asList(
                 Arrays.asList(1, 2, 3).iterator(),
                 Arrays.asList(4, 5, 6).iterator()
         ).iterator();
         final Iterator<Integer>  iter = ExtendedIterator.flatten(iteratorIterator);
         final List<Integer> actual = new ArrayList<>();
         iter.forEachRemaining(actual::add);
         assertEquals(collectionA, actual);
     }
 
     @Test
     public void testMap() {
         final List<Double> expected = Arrays.asList(0.5, 1., 1.5, 2.0, 2.5, 3.0);
         final Function<Integer, Double> function = i -> i / 2.0;
         final ExtendedIterator<Double> underTest = ExtendedIterator.create(collectionA.iterator()).map(function);
         final List<Double> actual = new ArrayList<>();
         underTest.forEachRemaining(actual::add);
         assertEquals(expected, actual);
     }
 
     @Test
     public void testRemove() {
         final Iterator<Integer> iter = ExtendedIterator.create(collectionA.iterator());
         final Integer i = iter.next();
         iter.remove();
         assertFalse(collectionA.contains(i));
         final List<Integer> actual = new ArrayList<>();
         iter.forEachRemaining(actual::add);
         assertEquals(collectionA, actual);
     }
 
     @Test
     public void testRemoveNext() {
         final ExtendedIterator<Integer> iter = ExtendedIterator.create(collectionA.iterator());
         final Integer i = iter.removeNext();
         assertFalse(collectionA.contains(i));
         final List<Integer> actual = new ArrayList<>();
         iter.forEachRemaining(actual::add);
         assertEquals(collectionA, actual);
     }
 }