content: /*
   * 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.causeway.viewer.wicket.model.whereAmI;
  
  import java.util.LinkedList;
  import java.util.List;
  import java.util.stream.Stream;
  
  import org.apache.causeway.core.metamodel.util.pchain.ParentChain;
  import org.apache.causeway.viewer.wicket.model.models.UiObjectWkt;
  
  /**
   * @since 2.0
   */
  public record WhereAmI(
          /** immutable start node of the navigable parent chain */
          UiObjectWkt startOfChain,
          List<Object> reversedChainOfParents,
          boolean isWhereAmIEnabled) {
  
      public static WhereAmI of(final UiObjectWkt startOfChain) {
          var mmc = startOfChain.getMetaModelContext();
          var settings = mmc.getConfiguration().getViewer().getWicket().getBreadcrumbs();
          var isWhereAmIEnabled = settings.isEnabled();
          int maxChainLength = settings.getMaxParentChainLength();
  
          var adapter = startOfChain.getObject();
          final Object startNode = adapter.getPojo();
  
          var reversedChainOfParents = new LinkedList<Object>();
  
          ParentChain.of(mmc.getSpecificationLoader())
              .streamParentChainOf(startNode, maxChainLength)
              .forEach(reversedChainOfParents::addFirst);
  
          return new WhereAmI(startOfChain, reversedChainOfParents, isWhereAmIEnabled);
      }
  
      /**
       * The navigable parent chain requires a minimum length of 2 in order to be shown.
       * @return whether the where-am-I hint should be shown or hidden
       */
      public boolean isShowWhereAmI() {
          if(!isWhereAmIEnabled) return false; // this will prevent rendering
  
          return !reversedChainOfParents.isEmpty();
      }
  
      /**
       * Streams the linked nodes of this model's navigable parent chain in reverse order.
       * @return reversed order stream of linked parent nodes, which does not include the start node
       */
      public Stream<UiObjectWkt> streamParentChainReversed() {
          if(!isWhereAmIEnabled) return Stream.empty(); //unexpected call, we could log a warning
  
          return reversedChainOfParents.stream()
                  .map(this::toEntityModel);
      }
  
      // -- HELPER
  
      private UiObjectWkt toEntityModel(final Object domainObject) {
          var objectAdapter = startOfChain.getMetaModelContext().getObjectManager().adapt(domainObject);
          return UiObjectWkt.ofAdapter(objectAdapter);
      }
  
  }
  