/**
 *
 * Copyright
 * 2009-2015 Jayway Products AB
 * 2016-2017 Föreningen Sambruk
 *
 * Licensed under AGPL, Version 3.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.gnu.org/licenses/agpl.txt
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package se.streamsource.streamflow.web.domain.interaction.gtd;

import org.qi4j.api.common.Optional;
import org.qi4j.api.entity.association.Association;
import org.qi4j.api.injection.scope.This;
import org.qi4j.api.mixin.Mixins;

import se.streamsource.streamflow.infrastructure.event.domain.DomainEvent;

/**
 * Generic mixin for anything that is ownable. Represents a child-parent relationship.
 */
@Mixins(Ownable.Mixin.class)
public interface Ownable
{
   void changeOwner( Owner owner );

   boolean isOwnedBy(Owner owner);

   boolean hasOwner();

   interface Data
   {
      @Optional
      Association<Owner> owner();
   }

   interface Events
   {
      void changedOwner( @Optional DomainEvent event, Owner newOwner );
   }

   class Mixin
         implements Ownable, Events
   {
      @This
      Data state;

      public void changeOwner( Owner owner )
      {
         if (owner.equals( state.owner().get() ))
            return; // Don't try to set to the same owner

         changedOwner( null, owner );
      }

      public boolean hasOwner()
      {
         return state.owner().get() != null;
      }

      public boolean isOwnedBy( Owner owner )
      {
         return owner.equals( state.owner().get() );
      }

      public void changedOwner( @Optional DomainEvent event, Owner newOwner )
      {
         state.owner().set( newOwner );
      }
   }
}