/*
    * 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
    *
    *     https://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.configuration2.tree;
  
  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.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * A test class for {@code InMemoryNodeModel} which tests functionality related to node references. This test class
   * creates a model for the test structure with authors data. Each node is associated a string reference object with the
   * node name. It can then be checked whether updates of the hierarchy do not affect the references.
   */
  public class TestInMemoryNodeModelReferences {
  
      /** A mock resolver. */
      private NodeKeyResolver<ImmutableNode> resolver;
  
      /** The test model. */
      private InMemoryNodeModel model;
  
      /**
       * Returns a flat collection of all nodes contained in the specified nodes hierarchy.
       *
       * @param root the root node of the hierarchy
       * @return a collection with all nodes in this hierarchy
       */
      private Collection<ImmutableNode> collectNodes(final ImmutableNode root) {
          final Set<ImmutableNode> nodes = new HashSet<>();
          NodeTreeWalker.INSTANCE.walkBFS(root, new ConfigurationNodeVisitorAdapter<ImmutableNode>() {
              @Override
              public void visitBeforeChildren(final ImmutableNode node, final NodeHandler<ImmutableNode> handler) {
                  nodes.add(node);
              }
          }, model.getNodeHandler());
          return nodes;
      }
  
      /**
       * Creates the initial reference data for the test hierarchy.
       *
       * @return the map with reference data
       */
      private Map<ImmutableNode, String> createReferences() {
          final Collection<ImmutableNode> nodes = collectNodes(NodeStructureHelper.ROOT_AUTHORS_TREE);
          nodes.remove(NodeStructureHelper.ROOT_AUTHORS_TREE);
          final Map<ImmutableNode, String> refs = new HashMap<>();
          for (final ImmutableNode node : nodes) {
              refs.put(node, node.getNodeName());
          }
          return refs;
      }
  
      @BeforeEach
      public void setUp() throws Exception {
          resolver = NodeStructureHelper.createResolverMock();
          NodeStructureHelper.prepareResolveKeyForQueries(resolver);
          NodeStructureHelper.prepareResolveAddKeys(resolver);
          model = new InMemoryNodeModel();
          final Map<ImmutableNode, String> references = createReferences();
          model.mergeRoot(NodeStructureHelper.ROOT_AUTHORS_TREE, null, references, NodeStructureHelper.ROOT_AUTHORS_TREE.getNodeName(), resolver);
      }
  
      /**
       * Tests whether the name of the root node can be changed during a merge operation.
       */
      @Test
      void testMergeRootOverrideName() {
          final ImmutableNode node = NodeStructureHelper.createNode("newNode", null);
          final String newName = "newRootNode";
  
          model.mergeRoot(node, newName, null, null, resolver);
         final ImmutableNode root = model.getNodeHandler().getRootNode();
         assertEquals(newName, root.getNodeName());
     }
 
     /**
      * Tests whether mergeRoot() handles an explicit reference object for the root node correctly.
      */
     @Test
     void testMergeRootReference() {
         final Object rootRef = 20140404210508L;
         final ImmutableNode node = NodeStructureHelper.createNode("newNode", null);
 
         model.mergeRoot(node, null, null, rootRef, resolver);
         final ReferenceNodeHandler refHandler = model.getReferenceNodeHandler();
         final ImmutableNode checkNode = NodeStructureHelper.nodeForKey(model, "Simmons/Ilium");
         assertEquals(checkNode.getNodeName(), refHandler.getReference(checkNode));
         assertEquals(rootRef, refHandler.getReference(refHandler.getRootNode()));
     }
 
     /**
      * Tests whether attributes are taken into account by a merge operation.
      */
     @Test
     void testMergeRootWithAttributes() {
         final ImmutableNode node = new ImmutableNode.Builder().addAttribute("key", "value").create();
         model.mergeRoot(node, null, null, null, resolver);
         final ImmutableNode root = model.getNodeHandler().getRootNode();
         assertEquals(Collections.singletonMap("key", "value"), root.getAttributes());
     }
 
     /**
      * Tests whether a value is taken into account when the root node is merged.
      */
     @Test
     void testMergeRootWithValue() {
         final ImmutableNode node = NodeStructureHelper.createNode("newNode", "test");
         model.mergeRoot(node, null, null, null, resolver);
         final ImmutableNode root = model.getNodeHandler().getRootNode();
         assertEquals(NodeStructureHelper.ROOT_AUTHORS_TREE.getNodeName(), root.getNodeName());
         assertEquals("test", root.getValue());
     }
 
     /**
      * Tests whether the stored references can be queried.
      */
     @Test
     void testQueryReferences() {
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         final Collection<ImmutableNode> nodes = collectNodes(handler.getRootNode());
         for (final ImmutableNode node : nodes) {
             assertEquals(node.getNodeName(), handler.getReference(node));
         }
     }
 
     /**
      * Tests whether references can be queried after an update operation.
      */
     @Test
     void testQueryReferencesAfterUpdate() {
         model.addProperty("Simmons.Hyperion", Collections.singleton("Lamia"), resolver);
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         assertEquals("Hyperion", handler.getReference(NodeStructureHelper.nodeForKey(model, "Simmons/Hyperion")));
         assertEquals("Simmons", handler.getReference(NodeStructureHelper.nodeForKey(model, "Simmons")));
     }
 
     /**
      * Tests the reference returned for an unknown node.
      */
     @Test
     void testQueryReferenceUnknown() {
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         assertNull(handler.getReference(new ImmutableNode.Builder().create()));
     }
 
     /**
      * Tests whether removed references can be queried.
      */
     @Test
     void testQueryRemovedReferencesAfterRemove() {
         model.clearTree("Simmons", resolver);
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         final List<Object> removedRefs = handler.removedReferences();
         final int authorIdx = 2;
         for (int i = 0; i < NodeStructureHelper.worksLength(authorIdx); i++) {
             assertTrue(removedRefs.contains(NodeStructureHelper.work(authorIdx, i)), "Work not found: " + i);
             for (int j = 0; j < NodeStructureHelper.personaeLength(authorIdx, i); j++) {
                 assertTrue(removedRefs.contains(NodeStructureHelper.persona(authorIdx, i, j)), "Persona not found: " + j);
             }
         }
     }
 
     /**
      * Tests whether the removed references can be queried if there are none.
      */
     @Test
     void testQueryRemovedReferencesEmpty() {
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         assertTrue(handler.removedReferences().isEmpty());
     }
 
     /**
      * Tests that the list with removed references cannot be modified.
      */
     @Test
     void testRemovedReferencesModify() {
         model.clearTree("Simmons", resolver);
         final ReferenceNodeHandler handler = model.getReferenceNodeHandler();
         final List<Object> removedRefs = handler.removedReferences();
         assertThrows(UnsupportedOperationException.class, () -> removedRefs.add("another one"));
     }
 
     /**
      * Tests whether the root node of the model can be replaced.
      */
     @Test
     void testReplaceRoot() {
         final NodeSelector selector = new NodeSelector("Simmons.Hyperion");
         model.trackNode(selector, resolver);
         final ImmutableNode trackedNode = model.getTrackedNode(selector);
         model.addProperty("Simmons.Hyperion.Lamia", Collections.singleton("new person"), resolver);
 
         model.replaceRoot(NodeStructureHelper.ROOT_AUTHORS_TREE, resolver);
         final ImmutableNode node = model.getTrackedNode(selector);
         assertEquals(trackedNode, node);
         assertFalse(model.isTrackedNodeDetached(selector));
         assertNull(model.getReferenceNodeHandler().getReference(trackedNode));
     }
 
     /**
      * Tries to call replaceRoot() with a null node.
      */
     @Test
     void testReplaceRootNull() {
         assertThrows(IllegalArgumentException.class, () -> model.replaceRoot(null, resolver));
     }
 }