/**
    * This file Copyright (c) 2019 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.editor;
  
  import info.magnolia.ui.api.i18n.I18NAuthoringSupport;
  import info.magnolia.ui.framework.ContextProperty;
  import info.magnolia.ui.framework.UiComponentContext;
  import info.magnolia.ui.framework.UiComponentContextProxy;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Locale;
  import java.util.Optional;
  import java.util.stream.Stream;
  
  /**
   * Typically used in various editors which let the editing of localised content
   * and support switching between supported languages within the same session.
   */
  public interface LocaleContext extends UiComponentContext {
  
      ContextProperty<Locale> current();
  
      ContextProperty<List<Locale>> availableLocales();
  
      ContextProperty<Locale> defaultLocale();
  
      default Stream<Locale> getAvailableLocales() {
          return availableLocales().value().map(List::stream).orElse(Stream.empty());
      }
  
      default Locale getCurrent() {
          return current().value().orElse(getDefault());
      }
  
      default Locale getDefault() {
          return defaultLocale().nullableValue();
      }
  
      default boolean isPopulated() {
          return availableLocales().value().map(locales -> locales.size() > 0).orElse(false);
      }
  
      default <T> void populateFromI18NAuthoringSupport(T item, I18NAuthoringSupport<T> i18NAuthoringSupport) {
          Locale defaultLocale = i18NAuthoringSupport.getDefaultLocale(item);
  
          if (defaultLocale == null) {
              restrictTo(Locale.getDefault());
              return;
          }
  
          List<Locale> availableLocales = Optional.ofNullable(i18NAuthoringSupport.getAvailableLocales(item))
                  .filter(locales -> !locales.isEmpty())
                  .orElse(Collections.singletonList(defaultLocale));
  
          defaultLocale().set(defaultLocale);
  
          if (!availableLocales.contains(current().nullableValue())) {
              current().set(defaultLocale);
          }
  
          availableLocales().set(availableLocales);
      }
  
      default void restrictTo(Locale locale) {
          defaultLocale().set(locale);
          current().set(locale);
          availableLocales().set(Collections.singletonList(locale));
     }
 
     /**
      * Creates a context bound to a single locale.
      */
     static LocaleContext of(Locale locale) {
         LocaleContext localeContext = new UiComponentContextProxy().createUiComponentContext(LocaleContext.class);
         localeContext.restrictTo(locale);
         return localeContext;
     }
 }