/**
 *
 * 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.infrastructure.event;

import java.io.IOException;
import java.util.Collection;
import java.util.LinkedList;
import java.util.TreeMap;

import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;
import org.qi4j.api.mixin.Mixins;
import org.qi4j.api.service.Activatable;
import org.qi4j.api.service.ServiceComposite;

import se.streamsource.streamflow.infrastructure.event.domain.TransactionDomainEvents;
import se.streamsource.streamflow.infrastructure.event.domain.source.AbstractEventStoreMixin;
import se.streamsource.streamflow.infrastructure.event.domain.source.EventSource;
import se.streamsource.streamflow.infrastructure.event.domain.source.EventStore;
import se.streamsource.streamflow.infrastructure.event.domain.source.EventStream;
import se.streamsource.streamflow.infrastructure.event.domain.source.TransactionVisitor;

/**
 * In-Memory EventStore. Mainly used for testing.
 */
@Mixins(MemoryEventStoreService.MemoryEventStoreMixin.class)
public interface MemoryEventStoreService
      extends EventSource, EventStore, EventStream, Activatable, ServiceComposite
{
   abstract class MemoryEventStoreMixin
         extends AbstractEventStoreMixin
      implements EventSource
   {
      // This holds all transactions
      private TreeMap<Long, String> store = new TreeMap<Long, String>();

      public void activate() throws IOException
      {
         super.activate();
      }

      public void passivate() throws Exception
      {
         super.passivate();
      }

      public void transactionsAfter( long afterTimestamp, TransactionVisitor visitor )
      {
         // Lock datastore first
         lock.lock();
         try
         {
            Long startTime = afterTimestamp + 1;
            Collection<String> txsAfterDate = store.tailMap( startTime ).values();

            for (String txJson : txsAfterDate)
            {
               JSONTokener tokener = new JSONTokener( txJson );
               JSONObject json = (JSONObject) tokener.nextValue();
               TransactionDomainEvents tx = (TransactionDomainEvents) transactionEventsType.fromJSON( json, module );

               if (!visitor.visit( tx ))
               {
                  return;
               }
            }
         } catch (JSONException e)
         {
            logger.warn( "Could not de-serialize events", e );
         } finally
         {
            lock.unlock();
         }
      }

      public void transactionsBefore( long beforeTimestamp, TransactionVisitor visitor )
      {
         // Lock datastore first
         lock.lock();
         try
         {
            Long startTime = beforeTimestamp - 1;
            Collection<String> txsBeforeDate = store.headMap( startTime ).values();

            // Reverse the list - this could be done more easily in JDK1.6
            LinkedList<String> values = new LinkedList<String>();
            for (String json : txsBeforeDate)
            {
               values.addFirst( json );
            }

            for (String txJson : values)
            {
               JSONTokener tokener = new JSONTokener( txJson );
               JSONObject json = (JSONObject) tokener.nextValue();
               TransactionDomainEvents tx = (TransactionDomainEvents) transactionEventsType.fromJSON( json, module );

               if (!visitor.visit( tx ))
               {
                  return;
               }
            }
         } catch (JSONException e)
         {
            logger.warn( "Could not de-serialize events", e );
         } finally
         {
            lock.unlock();
         }
      }

      protected void rollback()
            throws IOException
      {
      }

      protected void commit()
            throws IOException
      {
      }

      protected void storeEvents( TransactionDomainEvents transactionDomain )
            throws IOException
      {
         String jsonString = transactionDomain.toString();
         store.put( transactionDomain.timestamp().get(), jsonString );
      }
   }
}