/**
    * This file Copyright (c) 2018 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.ui.databinding;
  
  import info.magnolia.context.Context;
  import info.magnolia.jcr.predicate.AbstractPredicate;
  import info.magnolia.jcr.util.NodeUtil;
  import info.magnolia.ui.api.i18n.I18NAuthoringSupport;
  import info.magnolia.ui.framework.databinding.ItemProviderStrategy;
  import info.magnolia.ui.framework.databinding.MultiFieldOrderHandler;
  import info.magnolia.ui.field.EditorPropertyDefinition;
  
  import java.util.Collection;
  import java.util.List;
  import java.util.Locale;
  import java.util.Optional;
  import java.util.stream.Stream;
  import java.util.stream.StreamSupport;
  
  import javax.inject.Inject;
  import javax.inject.Provider;
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang3.RandomStringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import lombok.AllArgsConstructor;
  import lombok.SneakyThrows;
  
  /**
   * JCR implementation of the {@link MultiFieldOrderHandler}.
   */
  public class JcrChildNodeOrderHandler implements MultiFieldOrderHandler<Node> {
  
      private static final Logger log = LoggerFactory.getLogger(JcrChildNodeOrderHandler.class);
  
      private static final String INCREMENT_REGEX = "(\\d{1,3})";
  
      private final JcrChildNodeOrderHandlerDefinition definition;
  
      private final EditorPropertyDefinition propertyDefinition;
  
      private final I18NAuthoringSupport i18NAuthoringSupport;
  
      private final Provider<Context> contextProvider;
  
      @Inject
      public JcrChildNodeOrderHandler(JcrChildNodeOrderHandlerDefinition definition, EditorPropertyDefinition propertyDefinition, I18NAuthoringSupport i18NAuthoringSupport, Provider<Context> contextProvider) {
          this.definition = definition;
          this.propertyDefinition = propertyDefinition;
          this.i18NAuthoringSupport = i18NAuthoringSupport;
          this.contextProvider = contextProvider;
      }
  
      @Override
      public Stream<ItemProviderStrategy<Node>> readItems(Node parent, Locale locale) {
          return getChildNodes(parent, propertyDefinition.getName(), locale).map(node -> new AlwaysFetchJcrNodeFromNewSession(contextProvider, node));
      }
  
      @Override
      @SneakyThrows(RepositoryException.class)
      public Node getOrCreate(Node parent, String name, Locale locale) {
          return NodeUtil.createPath(parent, deriveLocaleAwareName(name, locale), definition.getNodeType());
      }
  
      @Override
     public void removeItems(Collection<Node> items) {
         items.forEach(node -> {
             try {
                 node.remove();
             } catch (RepositoryException e) {
                 log.warn("Failed to remove node: {}", e.getMessage());
             }
         });
     }
 
     @Override
     @SneakyThrows(RepositoryException.class)
     public void applyOrder(Node parent, List<Node> itemOrder, Locale locale) {
         for (int idx = 0; idx < itemOrder.size() - 1; idx++) {
             NodeUtil.orderAfter(itemOrder.get(idx + 1), itemOrder.get(idx).getName());
         }
 
         String baseName = propertyDefinition.getName();
 
         for (Node node : itemOrder) {
             String nodeName = deriveLocaleAwareName(baseName + itemOrder.indexOf(node), locale);
             if (parent.hasNode(nodeName)) {
                 NodeUtil.renameNode(parent.getNode(nodeName), RandomStringUtils.randomAlphanumeric(10));
             }
             NodeUtil.renameNode(node, nodeName);
         }
     }
 
     /**
      * @return The regex used to filter child items
      */
     private String childItemRegexRepresentation(String name) {
         return name + INCREMENT_REGEX;
     }
 
     private String deriveLocaleAwareName(String name, Locale locale) {
         if (i18NAuthoringSupport != null && locale != null && !i18NAuthoringSupport.isDefaultLocale(locale)) {
             return i18NAuthoringSupport.deriveLocalisedPropertyName(name, locale);
         }
         return name;
     }
 
     @SneakyThrows(RepositoryException.class)
     private Stream<Node> getChildNodes(Node node, String name, Locale locale) {
         return StreamSupport.stream(NodeUtil.getNodes(node, new NodeNameRegexPredicate(name, locale)).spliterator(), false);
     }
 
     @AllArgsConstructor
     private class NodeNameRegexPredicate extends AbstractPredicate<Node> {
 
         private final String baseName;
 
         private final Locale locale;
 
         @Override
         @SneakyThrows(RepositoryException.class)
         public boolean evaluateTyped(Node node) {
             return node.getName().matches(deriveLocaleAwareName(childItemRegexRepresentation(baseName), locale));
         }
     }
 
     private class AlwaysFetchJcrNodeFromNewSession implements ItemProviderStrategy<Node> {
 
         private final Provider<Context> contextProvider;
         private final String workspace;
         private final String identifier;
 
         @SneakyThrows(RepositoryException.class)
         AlwaysFetchJcrNodeFromNewSession(Provider<Context> contextProvider, Node node) {
             this.contextProvider = contextProvider;
             workspace = node.getSession().getWorkspace().getName();
             identifier = node.getIdentifier();
         }
 
         @Override
         @SneakyThrows(RepositoryException.class)
         public Optional<Node> read() {
             return Optional.of(contextProvider.get().getJCRSession(workspace).getNodeByIdentifier(identifier));
         }
     }
 }