/**
    * This file Copyright (c) 2014-2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.dam.external.app.contentview;
  
  import info.magnolia.dam.api.Folder;
  import info.magnolia.dam.api.ItemKey;
  import info.magnolia.dam.external.app.contentconnector.AssetContentConnector;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import com.vaadin.data.Container;
  
  /**
   * Hierarchical implementation of {@link AbstractAssetContainer}.
   */
  public class HierarchicalAssetContainer extends AbstractAssetContainer implements Container.Hierarchical {
  
      private List<ItemKey> rootItemKeys = new ArrayList<ItemKey>();
  
      private Map<ItemKey, List<ItemKey>> children = new HashMap<ItemKey, List<ItemKey>>();
  
      public HierarchicalAssetContainer(AssetContentConnector assetContentConnector) {
          super(assetContentConnector);
      }
  
      @Override
      public void refresh() {
          rootItemKeys.clear();
          children.clear();
          super.refresh();
      }
  
      /* {@link Container.Hierarchical} interface */
  
      @Override
      public Collection<ItemKey> getChildren(Object itemId) {
          final List<ItemKey> result = new ArrayList<ItemKey>();
  
          if (itemId instanceof ItemKey) {
              if (children.containsKey(itemId)) {
                  result.addAll(children.get(itemId));
              } else {
                  info.magnolia.dam.api.Item item = getAssetItem(itemId);
                  if (item != null && item.isFolder()) {
                      Iterator<info.magnolia.dam.api.Item> iterator = ((Folder) item).getChildren();
                      while (iterator.hasNext()) {
                          info.magnolia.dam.api.Item childItem = iterator.next();
                          result.add(childItem.getItemKey());
                          getItem(childItem.getItemKey());
                      }
                      children.put((ItemKey) itemId, result);
                  }
              }
          }
          return Collections.unmodifiableCollection(result);
      }
  
      @Override
      public ItemKey getParent(Object itemId) {
          if (!(itemId instanceof ItemKey)) {
              return null;
          }
         if (isRoot(itemId)) {
             return null;
         }
         info.magnolia.dam.api.Item item = getAssetItem(itemId);
         if (item == null || (item.isFolder() && ((Folder) item).isRoot())) {
             return null;
         }
         return item.getParent().getItemKey();
     }
 
     @Override
     public Collection<ItemKey> rootItemIds() {
         if (rootItemKeys.isEmpty()) {
             Iterator<info.magnolia.dam.api.Item> iterator = getAssetProvider().getRootFolder().getChildren();
             while (iterator.hasNext()) {
                 info.magnolia.dam.api.Item item = iterator.next();
                 rootItemKeys.add(item.getItemKey());
                 getItem(item.getItemKey());
             }
         }
         return Collections.unmodifiableCollection(rootItemKeys);
     }
 
     @Override
     public boolean areChildrenAllowed(Object itemId) {
         info.magnolia.dam.api.Item item = getAssetItem(itemId);
         if (item != null && item.isFolder()) {
             return true;
         }
         return false;
     }
 
     @Override
     public boolean isRoot(Object itemId) {
         info.magnolia.dam.api.Item item = getAssetItem(itemId);
         if (item == null) {
             return true;
         }
         if (item.isAsset()) {
             return false;
         }
         return ((Folder) item).isRoot();
     }
 
     @Override
     public boolean hasChildren(Object itemId) {
         info.magnolia.dam.api.Item item = getAssetItem(itemId);
         if (item == null || item.isAsset()) {
             return false;
         }
         return ((Folder) item).getChildren().hasNext();
     }
 
     @Override
     public List<String> getSortableContainerPropertyIds() {
         // at present tree view is not sortable
         return Collections.emptyList();
     }
 
     @Override
     public boolean setParent(Object itemId, Object newParentId) throws UnsupportedOperationException {
         throw new UnsupportedOperationException(
                 "Asset container does not support 'setParent()' operation");
     }
 
     @Override
     public boolean setChildrenAllowed(Object itemId, boolean areChildrenAllowed) throws UnsupportedOperationException {
         throw new UnsupportedOperationException(
                 "Asset container does not support 'setChildrenAllowed()' operation");
     }
 }