/*
    * Copyright 2015 Data Archiving and Networked Services (an institute of
    * Koninklijke Nederlandse Akademie van Wetenschappen), King's College London,
    * Georg-August-Universitaet Goettingen Stiftung Oeffentlichen Rechts
    *
    * Licensed under the EUPL, Version 1.1 or – as soon they will be approved by
    * the European Commission - subsequent versions of the EUPL (the "Licence");
    * You may not use this work except in compliance with the Licence.
    * You may obtain a copy of the Licence at:
   *
   * https://joinup.ec.europa.eu/software/page/eupl
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the Licence is distributed on an "AS IS" basis,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the Licence for the specific language governing
   * permissions and limitations under the Licence.
   */
  
  package eu.ehri.project.models;
  
  import com.tinkerpop.blueprints.Direction;
  import com.tinkerpop.blueprints.Vertex;
  import com.tinkerpop.frames.Adjacency;
  import com.tinkerpop.frames.modules.javahandler.JavaHandler;
  import com.tinkerpop.frames.modules.javahandler.JavaHandlerContext;
  import com.tinkerpop.gremlin.java.GremlinPipeline;
  import eu.ehri.project.definitions.Entities;
  import eu.ehri.project.definitions.Ontology;
  import eu.ehri.project.models.annotations.EntityType;
  import eu.ehri.project.models.annotations.Fetch;
  import eu.ehri.project.models.annotations.Meta;
  import eu.ehri.project.models.base.Accessible;
  import eu.ehri.project.models.base.Accessor;
  import eu.ehri.project.models.base.ItemHolder;
  import eu.ehri.project.models.base.Named;
  import eu.ehri.project.models.base.PermissionScope;
  import eu.ehri.project.models.utils.JavaHandlerUtils;
  
  /**
   * Frame class representing a group of users or other groups
   * that can be assigned permissions.
   */
  @EntityType(EntityClass.GROUP)
  public interface Group extends Accessor, Accessible,
          PermissionScope, Named, ItemHolder {
      
      String ADMIN_GROUP_IDENTIFIER = "admin";
      String ANONYMOUS_GROUP_IDENTIFIER = "anonymous";
      String ADMIN_GROUP_NAME = "Administrators";
  
      /**
       * Fetch the groups to which this group belongs.
       *
       * @return an iterable of group frames
       */
      @Fetch(Ontology.ACCESSOR_BELONGS_TO_GROUP)
      @Adjacency(label = Ontology.ACCESSOR_BELONGS_TO_GROUP)
      Iterable<Group> getGroups();
  
      /**
       * TODO FIXME use this in case we need AccesibleEnity's instead of Accessors, 
       */
      @Adjacency(label = Ontology.ACCESSOR_BELONGS_TO_GROUP, direction = Direction.IN)
      Iterable<Accessible> getMembersAsEntities();
  
      /**
       * Get members of this group.
       *
       * @return an iterable of user or group frames
       */
      @Adjacency(label = Ontology.ACCESSOR_BELONGS_TO_GROUP, direction = Direction.IN)
      Iterable<Accessor> getMembers();
  
      /**
       * Get the number of items within this group.
       *
       * @return a count of group members
       */
      @Meta(CHILD_COUNT)
      @JavaHandler
      int getChildCount();
  
      /**
       * Adds a Accessor as a member to this Group, so it has the permissions of the Group.
       *
       * @param accessor a user or group frame
       */
      @JavaHandler
      void addMember(Accessor accessor);
  
      /**
       * Removes a member from this group.
       *
       * @param accessor a user or group frame
       */
      @JavaHandler
      void removeMember(Accessor accessor);
  
     /**
      * Get <b>all</b> members of this group, including members of
      * groups within this group.
      *
      * @return an iterable of user or group frames
      */
     @JavaHandler
     Iterable<Accessible> getAllUserProfileMembers();
 
     /**
      * Implementation of complex methods.
      */
     abstract class Impl implements JavaHandlerContext<Vertex>, Group {
 
         public int getChildCount() {
             return Math.toIntExact(gremlin().inE(Ontology.ACCESSOR_BELONGS_TO_GROUP).count());
         }
 
         public void addMember(Accessor accessor) {
             JavaHandlerUtils.addUniqueRelationship(accessor.asVertex(), it(),
                     Ontology.ACCESSOR_BELONGS_TO_GROUP);
         }
 
         public void removeMember(Accessor accessor) {
             JavaHandlerUtils.removeAllRelationships(accessor.asVertex(),
                     it(), Ontology.ACCESSOR_BELONGS_TO_GROUP);
         }
 
         public Iterable<Accessible> getAllUserProfileMembers() {
             GremlinPipeline<Vertex,Vertex> pipe = gremlin().as("n").in(Ontology.ACCESSOR_BELONGS_TO_GROUP)
                     .loop("n", JavaHandlerUtils.defaultMaxLoops,
                             vertexLoopBundle -> vertexLoopBundle.getObject()
                                 .getProperty(EntityType.TYPE_KEY)
                                     .equals(Entities.USER_PROFILE));
             return frameVertices(pipe.dedup());
         }
     }
 }