/**
    * This file Copyright (c) 2013-2018 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.form.field.transformer.basic;
  
  import info.magnolia.objectfactory.Components;
  import info.magnolia.ui.api.i18n.I18NAuthoringSupport;
  import info.magnolia.ui.form.field.definition.ConfiguredFieldDefinition;
  import info.magnolia.ui.form.field.definition.OptionGroupFieldDefinition;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Set;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.vaadin.v7.data.Item;
  import com.vaadin.v7.data.Property;
  
  /**
   * Specific transformer for use with multi-select {@link OptionGroupFieldDefinition}.
   * <p>
   * Indeed, Vaadin's {@link com.vaadin.ui.OptionGroup OptionGroup} operates selection with sets, whereas we resolve
   * JCR multi-value properties as lists.
   * <p>
   * Also mind that for single-select definitions, this transformer merely works like a plain {@link BasicTransformer}.
   *
   * @param <T>
   */
  public class ListToSetTransformer<T> extends BasicTransformer<T> {
  
      private static final Logger log = LoggerFactory.getLogger(ListToSetTransformer.class);
  
      private final boolean multiselect;
  
      /**
       * @deprecated since 5.4.2 - use {@link #ListToSetTransformer(Item, ConfiguredFieldDefinition, Class, I18NAuthoringSupport)} instead.
       */
      @Deprecated
      public ListToSetTransformer(Item relatedFormItem, ConfiguredFieldDefinition definition, Class<T> type) {
          this(relatedFormItem, definition, type, Components.getComponent(I18NAuthoringSupport.class));
      }
  
      public ListToSetTransformer(Item relatedFormItem, ConfiguredFieldDefinition definition, Class<T> type, I18NAuthoringSupport i18NAuthoringSupport) {
          super(relatedFormItem, definition, type, i18NAuthoringSupport);
          if (definition instanceof OptionGroupFieldDefinition) {
              multiselect = ((OptionGroupFieldDefinition) definition).isMultiselect();
          } else {
              multiselect = false;
              log.info("ListToSetTransformer is intended for multiselect OptionGroupFieldDefinition, but definition was of type {}. This may behave like a plain BasicTransformer.", definition);
          }
      }
  
      @Override
      public void writeToItem(T newValue) {
          if (!multiselect) {
              super.writeToItem(newValue);
              return;
          }
  
          Property<T> p = getOrCreateProperty(type, false);
          if (isCollectionConversionNeeded(newValue, p.getType())) {
              newValue = (T) new LinkedList((Set) newValue);
          }
          if (newValue instanceof Collection && ((Collection) newValue).isEmpty()) {
              newValue = null;
         }
         p.setValue(newValue);
     }
 
     /**
      * Check if the newValue has to be transformed from a {@link Set} to a {@link List}. {@link Set} is used by Vaadin multi fields and multi values are stored as {@link List} in Jcr.
      */
     protected boolean isCollectionConversionNeeded(T newValue, Class<?> propertyType) {
         return List.class.isAssignableFrom(propertyType) && newValue instanceof Set;
     }
 
     @Override
     public T readFromItem() {
         if (!multiselect) {
             return super.readFromItem();
         }
 
         Property<T> p = getOrCreateProperty(type, false);
         if (definition.isReadOnly()) {
             p.setReadOnly(true);
         }
         T value = p.getValue();
         if (value != null && value instanceof List) {
             return (T) new HashSet((List) value);
         }
         return null;
     }
 
 }