/**
    * 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.field.factory;
  
  import info.magnolia.objectfactory.ComponentProvider;
  import info.magnolia.ui.field.ComboBoxFieldDefinition;
  import info.magnolia.ui.field.SelectFieldSupport;
  
  import java.util.Optional;
  import java.util.stream.Stream;
  
  import javax.inject.Inject;
  
  import com.vaadin.data.provider.AbstractDataProvider;
  import com.vaadin.data.provider.DataProvider;
  import com.vaadin.data.provider.Query;
  import com.vaadin.ui.ComboBox;
  
  
  /**
   * Creates and initializes a ComboBox selection field based on its field definition.
   * @param <T> type of select option
   *
   */
  public class ComboBoxFieldFactory<T, D extends ComboBoxFieldDefinition<T>> extends AbstractSelectFieldFactory<D, T> {
  
      @Inject
      public ComboBoxFieldFactory(D definition, ComponentProvider componentProvider, SelectFieldSupport<T> selectFieldSupport) {
          super(definition, componentProvider, selectFieldSupport);
      }
  
      @Override
      protected ComboBox<T> createFieldComponent() {
          final ComboBox<T> select = new ComboBox<>();
          select.addAttachListener(event -> {
              if (!select.isEnabled()) {
                  select.setDataProvider(EmptyDataProvider.getInstance());
              }
          });
          select.setScrollToSelectedItem(getDefinition().isScrollToSelectedItem());
          select.setEmptySelectionAllowed(getDefinition().isEmptySelectionAllowed());
          select.setTextInputAllowed(getDefinition().isTextInputAllowed());
          select.setPopupWidth(getDefinition().getPopWidth());
          select.setEmptySelectionCaption(getDefinition().getEmptySelectionCaption());
          select.setPlaceholder(getDefinition().getPlaceholder());
          select.setPageLength(getDefinition().getPageLength());
          select.setNewItemProvider(Optional.ofNullable(getDefinition().getNewItemProviderClass())
                  .map(aClass -> componentProvider.newInstance(aClass))
                  .orElse(null)
          );
          return select;
      }
  
      @Override
      protected DataProvider<T, String> getDataProvider() {
          return getDefinition().isReadOnly() ? EmptyDataProvider.getInstance() : super.getDataProvider();
      }
  
      static class EmptyDataProvider<T> extends AbstractDataProvider<T, String> {
  
          private static final EmptyDataProvider<?> INSTANCE = new EmptyDataProvider<>();
  
          @Override
          public boolean isInMemory() {
              return true;
          }
  
          @Override
         public int size(Query<T, String> query) {
             return 0;
         }
 
         @Override
         public Stream<T> fetch(Query<T, String> query) {
             return Stream.empty();
         }
 
         public static <T> EmptyDataProvider<T> getInstance() {
             return (EmptyDataProvider<T>) INSTANCE;
         }
     }
 }