/**
    * This file Copyright (c) 2020 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.datasource.locale;
  
  import info.magnolia.context.Context;
  import info.magnolia.icons.MagnoliaIcons;
  import info.magnolia.ui.editor.LocaleContext;
  import info.magnolia.ui.field.SelectFieldSupport;
  
  import java.util.Locale;
  import java.util.Optional;
  import java.util.stream.Stream;
  
  import javax.inject.Inject;
  
  import com.vaadin.data.Converter;
  import com.vaadin.data.Result;
  import com.vaadin.data.ValueContext;
  import com.vaadin.data.provider.AbstractDataProvider;
  import com.vaadin.data.provider.Query;
  import com.vaadin.ui.IconGenerator;
  import com.vaadin.ui.ItemCaptionGenerator;
  
  /**
   * {@link info.magnolia.ui.field.SelectFieldSupport} implementation based on available {@link java.util.Locale}s for content.
   * {@link #defaultConverter()} uses IETF BCP 47 language tag. See {@link Locale#toLanguageTag()} and {@link Locale#forLanguageTag(String)}.
   */
  public class LocaleSelectFieldSupport implements SelectFieldSupport<Locale> {
  
      private final LocaleContext localeContext;
      private final Context context;
  
      @Inject
      public LocaleSelectFieldSupport(LocaleContext localeContext, Context context) {
          this.localeContext = localeContext;
          this.context = context;
      }
  
      @Override
      public LocaleListProvider getDataProvider() {
          return new LocaleListProvider(localeContext);
      }
  
      @Override
      public ItemCaptionGenerator<Locale> getItemCaptionGenerator() {
          return locale -> {
              String label = locale.getDisplayLanguage(context.getLocale());
              String displayCountry = locale.getDisplayCountry(context.getLocale());
  
              return displayCountry.isEmpty() ? label : label + " (" + displayCountry + ")";
          };
      }
  
      @Override
      public IconGenerator<Locale> getIconGenerator() {
          return locale -> MagnoliaIcons.LANGUAGE_APP;
      }
  
      @Override
      public Converter<Locale, String> defaultConverter() {
          return new Converter<Locale, String>() {
              @Override
              public Result<String> convertToModel(Locale value, ValueContext context) {
                  return Result.ok(
                          Optional.ofNullable(value)
                                  .map(Locale::toLanguageTag)
                                  .orElse(null));
              }
 
             @Override
             public Locale convertToPresentation(String value, ValueContext context) {
                 return Optional.ofNullable(value)
                         .map(Locale::forLanguageTag)
                         .orElse(null);
             }
         };
     }
 
     private static class LocaleListProvider extends AbstractDataProvider<Locale, String> {
 
         private final LocaleContext localeContext;
 
         public LocaleListProvider(LocaleContext localeContext) {
             this.localeContext = localeContext;
 
             localeContext.availableLocales().observe(locales -> this.refreshAll());
         }
 
         @Override
         public boolean isInMemory() {
             return true;
         }
 
         @Override
         public int size(Query<Locale, String> query) {
             return (int) fetch(query).count();
         }
 
         @Override
         public Stream<Locale> fetch(Query<Locale, String> query) {
             return localeContext.getAvailableLocales().skip(query.getOffset()).limit(query.getLimit());
         }
     }
 
 }