/**
    * 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.admincentral.apps.notifications;
  
  import static java.util.stream.Collectors.toMap;
  
  import info.magnolia.cms.security.User;
  import info.magnolia.context.Context;
  import info.magnolia.context.MgnlContext;
  import info.magnolia.objectfactory.Components;
  import info.magnolia.ui.api.message.Message;
  import info.magnolia.ui.filter.DataFilter;
  import info.magnolia.ui.framework.message.MessagesManager;
  
  import java.util.Map;
  import java.util.stream.Stream;
  
  import javax.inject.Inject;
  
  import com.vaadin.data.provider.AbstractBackEndDataProvider;
  import com.vaadin.data.provider.Query;
  import com.vaadin.data.provider.QuerySortOrder;
  import com.vaadin.shared.data.sort.SortDirection;
  
  /**
   * Provide consolidated APIs to work on {@link Message}.
   */
  public class NotificationDataProvider extends AbstractBackEndDataProvider<Message, DataFilter> {
  
      private final MessagesManager messagesManager;
      private final NotificationDataSourceDefinition definition;
      private final NotificationDataSourceObservation datasourceObservation;
      private final User user;
  
      @Inject
      NotificationDataProvider(MessagesManager messagesManager, NotificationDataSourceDefinition definition, NotificationDataSourceObservation datasourceObservation, Context context) {
          this.messagesManager = messagesManager;
          this.definition = definition;
          this.datasourceObservation = datasourceObservation;
          this.user = context.getUser();
      }
  
      /**
       * @deprecated since 6.2.3. Use {@link #NotificationDataProvider(info.magnolia.ui.framework.message.MessagesManager, NotificationDataSourceDefinition, NotificationDataSourceObservation, info.magnolia.context.Context)} instead.
       */
      @Deprecated
      public NotificationDataProvider(MessagesManager messagesManager, NotificationDataSourceDefinition definition) {
          this(messagesManager, definition, Components.getComponent(NotificationDataSourceObservation.class), Components.getComponent(Context.class));
      }
  
      @Override
      public boolean isInMemory() {
          return false;
      }
  
      @Override
      public int sizeInBackEnd(Query<Message, DataFilter> query) {
          Long size = messagesManager.getMessagesAmount(MgnlContext.getUser().getName(), this.definition.getRelevantMessageTypes());
          return size.intValue();
      }
  
      @Override
      public Stream<Message> fetchFromBackEnd(Query<Message, DataFilter> query) {
  
          final Map<String, Boolean> sortCriteria = query.getSortOrders().stream()
                  .collect(toMap(
                          QuerySortOrder::getSorted,
                          so -> so.getDirection() == SortDirection.ASCENDING,
                         (a, b) -> b));
 
         // by default, sort result set by timestamp
         if (sortCriteria.isEmpty()) {
             sortCriteria.put("timestamp", true);
         }
         int limit = query.getLimit();
         int offset = query.getOffset();
 
         try {
             return messagesManager.getMessageBatch(MgnlContext.getUser().getName(), this.definition.getRelevantMessageTypes(), sortCriteria, limit, offset).stream();
         } catch (Exception e) {
             // the exception is propagated to info.magnolia.admincentral.AdmincentralErrorHandler#error which sends message, which in turn refreshes these providers resulting in loop
             // as the app is already broken at this point, we can destroy @AppScoped observation to prevent the loop
             datasourceObservation.destroy();
             throw e;
         }
     }
 }