/*
    * 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.assertSame;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.util.HashSet;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  
  import org.apache.commons.collections4.MapIterator;
  import org.junit.jupiter.api.Test;
  
  /**
   * Abstract class for testing the MapIterator interface.
   * <p>
   * This class provides a framework for testing an implementation of MapIterator.
   * Concrete subclasses must provide the list iterator to be tested.
   * They must also specify certain details of how the list iterator operates by
   * overriding the supportsXxx() methods if necessary.
   */
  public abstract class AbstractMapIteratorTest<K, V> extends AbstractIteratorTest<K> {
  
      /**
       * JUnit constructor.
       *
       * @param testName  the test class name
       */
      public AbstractMapIteratorTest(final String testName) {
          super(testName);
      }
  
      /**
       * The values to be used in the add and set tests.
       * Default is two strings.
       */
      @SuppressWarnings("unchecked")
      public V[] addSetValues() {
          return (V[]) new Object[] { "A", "B" };
      }
  
      /**
       * Implement this method to return the confirmed map which contains the same
       * data as the iterator.
       *
       * @return a full map which can be updated
       */
      public abstract Map<K, V> getConfirmedMap();
  
      /**
       * Implement this method to return the map which contains the same data as the
       * iterator.
       *
       * @return a full map which can be updated
       */
      public abstract Map<K, V> getMap();
  
      /**
       * Whether the get operation on the map structurally modifies the map,
       * such as with LRUMap. Default is false.
       *
       * @return true if the get method structurally modifies the map
       */
      public boolean isGetStructuralModify() {
          return false;
      }
  
      /**
       * Implement this method to return a map iterator over an empty map.
       *
       * @return an empty iterator
       */
      @Override
      public abstract MapIterator<K, V> makeEmptyIterator();
  
      /**
       * Implement this method to return a map iterator over a map with elements.
       *
       * @return a full iterator
      */
     @Override
     public abstract MapIterator<K, V> makeObject();
 
     /**
      * Whether or not we are testing an iterator that supports setValue().
      * Default is true.
      *
      * @return true if Iterator supports set
      */
     public boolean supportsSetValue() {
         return true;
     }
 
     /**
      * Test that the empty list iterator contract is correct.
      */
     @Test
     public void testEmptyMapIterator() {
         if (!supportsEmptyIterator()) {
             return;
         }
 
         final MapIterator<K, V> it = makeEmptyIterator();
         assertFalse(it.hasNext());
 
         // next() should throw a NoSuchElementException
         assertThrows(NoSuchElementException.class, () -> it.next());
 
         // getKey() should throw an IllegalStateException
         assertThrows(IllegalStateException.class, () -> it.getKey());
 
         // getValue() should throw an IllegalStateException
         assertThrows(IllegalStateException.class, () -> it.getValue());
 
         if (!supportsSetValue()) {
             // setValue() should throw an UnsupportedOperationException/IllegalStateException
             try {
                 it.setValue(addSetValues()[0]);
                 fail();
             } catch (final UnsupportedOperationException | IllegalStateException ex) {
                 // ignore
             }
         } else {
             // setValue() should throw an IllegalStateException
             assertThrows(IllegalStateException.class, () -> it.setValue(addSetValues()[0]));
         }
     }
 
     /**
      * Test that the full list iterator contract is correct.
      */
     @Test
     public void testFullMapIterator() {
         if (!supportsFullIterator()) {
             return;
         }
 
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> map = getMap();
         assertTrue(it.hasNext());
 
         assertTrue(it.hasNext());
         final Set<K> set = new HashSet<>();
         while (it.hasNext()) {
             // getKey
             final K key = it.next();
             assertSame(key, it.getKey(), "it.next() should equals getKey()");
             assertTrue(map.containsKey(key),  "Key must be in map");
             assertTrue(set.add(key), "Key must be unique");
 
             // getValue
             final V value = it.getValue();
             if (!isGetStructuralModify()) {
                 assertSame(map.get(key), value, "Value must be mapped to key");
             }
             assertTrue(map.containsValue(value),  "Value must be in map");
 
             verify();
         }
     }
 
     @Test
     public void testMapIteratorRemoveGetKey() {
         if (!supportsRemove()) {
             return;
         }
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> confirmed = getConfirmedMap();
 
         assertTrue(it.hasNext());
         final K key = it.next();
 
         it.remove();
         confirmed.remove(key);
         verify();
 
         assertThrows(IllegalStateException.class, () -> it.getKey());
         verify();
     }
 
     @Test
     public void testMapIteratorRemoveGetValue() {
         if (!supportsRemove()) {
             return;
         }
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> confirmed = getConfirmedMap();
 
         assertTrue(it.hasNext());
         final K key = it.next();
 
         it.remove();
         confirmed.remove(key);
         verify();
 
         assertThrows(IllegalStateException.class, () -> it.getValue());
         verify();
     }
 
     @Test
     public void testMapIteratorSet() {
         if (!supportsFullIterator()) {
             return;
         }
 
         final V newValue = addSetValues()[0];
         final V newValue2 = addSetValues().length == 1 ? addSetValues()[0] : addSetValues()[1];
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> map = getMap();
         final Map<K, V> confirmed = getConfirmedMap();
         assertTrue(it.hasNext());
         final K key = it.next();
         final V value = it.getValue();
 
         if (!supportsSetValue()) {
             assertThrows(UnsupportedOperationException.class, () -> it.setValue(newValue));
             return;
         }
         final V old = it.setValue(newValue);
         confirmed.put(key, newValue);
         assertSame(key, it.getKey(), "Key must not change after setValue");
         assertSame(newValue, it.getValue(), "Value must be changed after setValue");
         assertSame(value, old, "setValue must return old value");
         assertTrue(map.containsKey(key), "Map must contain key");
         // test against confirmed, as map may contain value twice
         assertEquals(confirmed.containsValue(old), map.containsValue(old),
             "Map must not contain old value");
         assertTrue(map.containsValue(newValue), "Map must contain new value");
         verify();
 
         it.setValue(newValue);  // same value - should be OK
         confirmed.put(key, newValue);
         assertSame(key, it.getKey(), "Key must not change after setValue");
         assertSame(newValue, it.getValue(), "Value must be changed after setValue");
         verify();
 
         it.setValue(newValue2);  // new value
         confirmed.put(key, newValue2);
         assertSame(key, it.getKey(), "Key must not change after setValue");
         assertSame(newValue2, it.getValue(), "Value must be changed after setValue");
         verify();
     }
 
     @Test
     public void testMapIteratorSetRemoveSet() {
         if (!supportsSetValue() || !supportsRemove()) {
             return;
         }
         final V newValue = addSetValues()[0];
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> confirmed = getConfirmedMap();
 
         assertTrue(it.hasNext());
         final K key = it.next();
 
         it.setValue(newValue);
         it.remove();
         confirmed.remove(key);
         verify();
 
         assertThrows(IllegalStateException.class, () -> it.setValue(newValue));
         verify();
     }
 
     @Test
     @Override
     public void testRemove() { // override
         final MapIterator<K, V> it = makeObject();
         final Map<K, V> map = getMap();
         final Map<K, V> confirmed = getConfirmedMap();
         assertTrue(it.hasNext());
         final K key = it.next();
 
         if (!supportsRemove()) {
             assertThrows(UnsupportedOperationException.class, () -> it.remove());
             return;
         }
 
         it.remove();
         confirmed.remove(key);
         assertFalse(map.containsKey(key));
         verify();
 
         try {
             it.remove();  // second remove fails
         } catch (final IllegalStateException ex) {
         }
         verify();
     }
 
 }