/*
    * 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.List;
  import java.util.ListIterator;
  import java.util.NoSuchElementException;
  
  import org.apache.commons.collections4.ResettableListIterator;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests the ListIteratorWrapper to ensure that it simulates
   * a ListIterator correctly.
   *
   * @param <E> the type of elements tested by this iterator.
   */
  public class ListIteratorWrapperTest<E> extends AbstractIteratorTest<E> {
  
      protected String[] testArray = {
          "One", "Two", "Three", "Four", "Five", "Six"
      };
  
      protected List<E> list1;
  
      @Override
      public ResettableListIterator<E> makeEmptyIterator() {
          final ArrayList<E> list = new ArrayList<>();
          return new ListIteratorWrapper<>(list.iterator());
      }
  
      @Override
      public ResettableListIterator<E> makeObject() {
          return new ListIteratorWrapper<>(list1.iterator());
      }
  
      @BeforeEach
      @SuppressWarnings("unchecked")
      public void setUp() {
          list1 = new ArrayList<>();
          list1.add((E) "One");
          list1.add((E) "Two");
          list1.add((E) "Three");
          list1.add((E) "Four");
          list1.add((E) "Five");
          list1.add((E) "Six");
      }
  
      @Test
      public void testIterator() {
          final ListIterator<E> iter = makeObject();
          for (final String testValue : testArray) {
              final Object iterValue = iter.next();
              assertEquals(testValue, iterValue, "Iteration value is correct");
          }
          assertFalse(iter.hasNext(), "Iterator should now be empty");
          assertThrows(NoSuchElementException.class, iter::next);
          // now, read it backwards
          for (int i = testArray.length - 1; i > -1; --i) {
              final Object testValue = testArray[i];
              final E iterValue = iter.previous();
              assertEquals(testValue, iterValue, "Iteration value is correct");
          }
          assertThrows(NoSuchElementException.class, iter::previous);
          // now, read it forwards again
          for (final String testValue : testArray) {
              final Object iterValue = iter.next();
              assertEquals(testValue, iterValue, "Iteration value is correct");
          }
      }
  
      @Test
      @Override
      public void testRemove() {
          final ListIterator<E> iter = makeObject();
  
          //initial state:
          assertEquals(-1, iter.previousIndex());
          assertEquals(0, iter.nextIndex());
 
         assertThrows(IllegalStateException.class, () -> iter.remove(),
                 "ListIteratorWrapper#remove() should fail; must be initially positioned first");
 
         //no change from invalid op:
         assertEquals(-1, iter.previousIndex());
         assertEquals(0, iter.nextIndex());
 
         //establish size:
         int sz = list1.size();
 
         //verify initial next() call:
         assertEquals(list1.get(0), iter.next());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
 
         //verify remove():
         iter.remove();
         assertEquals(--sz, list1.size());
         //like we never started iterating:
         assertEquals(-1, iter.previousIndex());
         assertEquals(0, iter.nextIndex());
 
         assertThrows(IllegalStateException.class, () -> iter.remove(),
                 "ListIteratorWrapper#remove() should fail; must be repositioned first");
 
         //no change from invalid op:
         assertEquals(-1, iter.previousIndex());
         assertEquals(0, iter.nextIndex());
 
         //two consecutive next() calls:
         assertEquals(list1.get(0), iter.next());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
 
         assertEquals(list1.get(1), iter.next());
         assertEquals(1, iter.previousIndex());
         assertEquals(2, iter.nextIndex());
 
         //call previous():
         assertEquals(list1.get(1), iter.previous());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
 
         //should support remove() after calling previous() once from tip because we haven't changed the underlying iterator's position:
         iter.remove();
         assertEquals(--sz, list1.size());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
 
         //dig into cache
         assertEquals(list1.get(0), iter.previous());
         assertEquals(-1, iter.previousIndex());
         assertEquals(0, iter.nextIndex());
 
         assertThrows(IllegalStateException.class, () -> iter.remove(),
                 "ListIteratorWrapper does not support the remove() method while dug into the cache via previous()");
 
         //no change from invalid op:
         assertEquals(-1, iter.previousIndex());
         assertEquals(0, iter.nextIndex());
 
         //dig out of cache, first next() maintains current position:
         assertEquals(list1.get(0), iter.next());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
         //continue traversing underlying iterator with this next() call, and we're out of the hole, so to speak:
         assertEquals(list1.get(1), iter.next());
         assertEquals(1, iter.previousIndex());
         assertEquals(2, iter.nextIndex());
 
         //verify remove() works again:
         iter.remove();
         assertEquals(--sz, list1.size());
         assertEquals(0, iter.previousIndex());
         assertEquals(1, iter.nextIndex());
 
         assertEquals(list1.get(1), iter.next());
         assertEquals(1, iter.previousIndex());
         assertEquals(2, iter.nextIndex());
 
     }
 
     @Test
     public void testReset() {
         final ResettableListIterator<E> iter = makeObject();
         final E first = iter.next();
         final E second = iter.next();
 
         iter.reset();
 
         // after reset, there shouldn't be any previous elements
         assertFalse(iter.hasPrevious(), "No previous elements after reset()");
 
         // after reset, the results should be the same as before
         assertEquals(first, iter.next(), "First element should be the same");
         assertEquals(second, iter.next(), "Second element should be the same");
 
         // after passing the point, where we reset, continuation should work as expected
         for (int i = 2; i < testArray.length; i++) {
             final Object testValue = testArray[i];
             final E iterValue = iter.next();
 
             assertEquals(testValue, iterValue, "Iteration value is correct");
         }
     }
 
 }