/**
    * 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.task.app;
  
  import info.magnolia.context.Context;
  import info.magnolia.jcr.util.NodeTypes;
  import info.magnolia.task.Task;
  import info.magnolia.task.TasksManager;
  import info.magnolia.ui.contentapp.DataFilter;
  
  import java.util.List;
  import java.util.Map;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import javax.inject.Provider;
  
  import org.apache.commons.lang3.StringUtils;
  
  import com.vaadin.data.provider.AbstractDataProvider;
  import com.vaadin.data.provider.Query;
  import com.vaadin.data.provider.QuerySortOrder;
  import com.vaadin.shared.data.sort.SortDirection;
  
  /**
   * {@link AbstractDataProvider} implementation capable of serving {@link Task} objects via {@link TasksManager}.
   */
  public class TasksDataProvider extends AbstractDataProvider<Task, DataFilter> {
  
      private final TasksManager tasksManager;
      private final Provider<Context> contextProvider;
      private final List<Task.Status> displayedTaskStatus;
  
      public TasksDataProvider(TasksManager tasksManager, Provider<Context> contextProvider, TasksDataSourceDefinition tasksDataSourceDefinition) {
          this.tasksManager = tasksManager;
          this.contextProvider = contextProvider;
          this.displayedTaskStatus = tasksDataSourceDefinition.getRelevantStatuses();
      }
  
      long size() {
          return tasksManager.getTasksAmountByUserAndStatus(contextProvider.get().getUser().getName(), displayedTaskStatus);
      }
  
      @Override
      public Stream<Task> fetch(Query<Task, DataFilter> query) {
          final Map<String, Boolean> sortCriteria = query.getSortOrders().stream()
                  .collect(Collectors.toMap(QuerySortOrder::getSorted, so -> so.getDirection() == SortDirection.ASCENDING, (a, b) -> b));
  
          // by default, sort result set by timestamp
          if (sortCriteria.isEmpty()) {
              sortCriteria.put(NodeTypes.LastModified.NAME, true);
          }
  
          return tasksManager
                  .findTasksByUserAndStatus(contextProvider.get().getUser().getName(), displayedTaskStatus, sortCriteria, query.getLimit(), query.getOffset())
                  .stream()
                  .filter(task -> pathFilterIsEmptyOrEqualsTaskPath(query, task));
      }
  
      private boolean pathFilterIsEmptyOrEqualsTaskPath(Query<Task, DataFilter> query, Task task) {
          return query.getFilter()
                  .map(DataFilter::getPathFilter)
                  .filter(StringUtils::isNotEmpty)
                  .map(pathFilter -> task.getPath().equals(pathFilter))
                  .orElse(true);
      }
  
      @Override
     public boolean isInMemory() {
         return true;
     }
 
     @Override
     public int size(Query<Task, DataFilter> query) {
         // not nice but legal and unlikely to break unless a user wants to
         // keep 2147483647+1 tasks  w/o never cleaning up
         return (int) size();
     }
 }