package com.atlassian.cache.ehcache;
   
   import java.util.SortedMap;
   
   import javax.annotation.Nonnull;
   import javax.annotation.Nullable;
   
   import com.atlassian.cache.CacheException;
   import com.atlassian.cache.CacheSettings;
  import com.atlassian.cache.CacheStatisticsKey;
  import com.atlassian.cache.CachedReference;
  import com.atlassian.cache.CachedReferenceListener;
  import com.atlassian.cache.ehcache.wrapper.ValueProcessor;
  import com.atlassian.cache.impl.CachedReferenceListenerSupport;
  import com.atlassian.cache.impl.LazyCachedReferenceListenerSupport;
  import com.atlassian.cache.impl.ReferenceKey;
  import java.util.function.Supplier;
  
  import com.google.common.collect.ImmutableSortedMap;
  
  import net.sf.ehcache.Ehcache;
  import net.sf.ehcache.Element;
  import net.sf.ehcache.event.CacheEventListener;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static com.atlassian.cache.ehcache.DelegatingCacheStatistics.toStatistics;
  import static com.atlassian.cache.ehcache.wrapper.WrapperUtils.unwrapElement;
  
  /**
   * A Lazy Reference that delegates to EhCache.
   *
   * @since 2.0
   */
  class DelegatingCachedReference<V> extends ManagedCacheSupport implements CachedReference<V>
  {
      private final Ehcache delegate;
      private final CachedReferenceListenerSupport<V> listenerSupport = new LazyCachedReferenceListenerSupport<V>()
      {
          @Override
          protected void init()
          {
              delegate.getCacheEventNotificationService().registerListener(new DelegatingReferenceCacheEventListener());
          }
      };
  
      private final Logger eventLogger;
      private final Logger stacktraceLogger;
  
      private final ValueProcessor valueProcessor;
  
      private DelegatingCachedReference(final Ehcache delegate, CacheSettings settings, final ValueProcessor valueProcessor)
      {
          super(delegate, settings);
          this.delegate = delegate;
          this.eventLogger = LoggerFactory.getLogger("com.atlassian.cache.event." + delegate.getName());
          this.stacktraceLogger = LoggerFactory.getLogger("com.atlassian.cache.stacktrace." + delegate.getName());
          this.valueProcessor = valueProcessor;
      }
  
      static <V> DelegatingCachedReference<V> create(final Ehcache delegate, CacheSettings settings, final ValueProcessor valueProcessor)
      {
          return new DelegatingCachedReference<V>(delegate, settings, valueProcessor);
      }
  
      @Nonnull
      @SuppressWarnings("unchecked")
      @Override
      public V get()
      {
          try
          {
              return (V) unwrap(delegate.get(wrap(ReferenceKey.KEY))).getObjectValue();
          }
          catch (net.sf.ehcache.CacheException e)
          {
              throw new CacheException(e.getCause());
          }
          catch (Exception e)
          {
              throw new CacheException(e);
          }
      }
  
      @Override
      public void reset()
      {
          try
          {
              delegate.remove(wrap(ReferenceKey.KEY));
              eventLogger.info("Cache {} was flushed", delegate.getName());
              if (stacktraceLogger.isInfoEnabled()) {
                  stacktraceLogger.info("Cache {} was flushed. Stacktrace:", delegate.getName(), new Exception());
              }
          }
          catch (Exception e)
          {
              throw new CacheException(e);
          }
     }
 
     @Override
     public void clear()
     {
         reset();
     }
 
     public boolean equals(@Nullable final Object other)
     {
         if (other instanceof DelegatingCachedReference)
         {
             DelegatingCachedReference<?> otherDelegatingReference = (DelegatingCachedReference<?>) other;
             if (delegate.equals(otherDelegatingReference.delegate))
             {
                 return true;
             }
         }
         return false;
     }
 
     @Override
     public int hashCode()
     {
         return 3 + delegate.hashCode();
     }
 
     @Nonnull
     @Override
     public SortedMap<CacheStatisticsKey,Supplier<Long>> getStatistics()
     {
         if (isStatisticsEnabled())
         {
             return toStatistics(delegate.getStatistics());
         }
         else
         {
             return ImmutableSortedMap.of();
         }
     }
 
     @Override
     public void addListener(@Nonnull CachedReferenceListener<V> listener, boolean includeValues)
     {
         listenerSupport.add(listener, includeValues);
     }
 
     private Object wrap(Object o) {
         return valueProcessor.wrap(o);
     }
 
     private Object unwrap(Object o) {
         return valueProcessor.unwrap(o);
     }
 
     private Element unwrap(Element element) {
         return unwrapElement(element, valueProcessor);
     }
 
     @Override
     public void removeListener(@Nonnull CachedReferenceListener<V> listener)
     {
         listenerSupport.remove(listener);
     }
 
     private class DelegatingReferenceCacheEventListener implements CacheEventListener
     {
         @Override
         public void notifyElementRemoved(Ehcache ehcache, Element element) throws net.sf.ehcache.CacheException
         {
             listenerSupport.notifyReset((V) unwrap(element.getObjectValue()));
         }
 
         @Override
         public void notifyElementPut(Ehcache ehcache, Element element) throws net.sf.ehcache.CacheException
         {
             listenerSupport.notifySet((V) unwrap(element.getObjectValue()));
         }
 
         @Override
         public void notifyElementUpdated(Ehcache ehcache, Element element) throws net.sf.ehcache.CacheException
         {
             listenerSupport.notifySet((V) unwrap(element.getObjectValue()));
         }
 
         @Override
         public void notifyElementExpired(Ehcache ehcache, Element element)
         {
             listenerSupport.notifyEvict((V) unwrap(element.getObjectValue()));
         }
 
         @Override
         public void notifyElementEvicted(Ehcache ehcache, Element element)
         {
             listenerSupport.notifyEvict((V) unwrap(element.getObjectValue()));
         }
 
         @Override
         public void notifyRemoveAll(Ehcache ehcache)
         {
             listenerSupport.notifyReset((V) null);
         }
 
         @Override
         public void dispose()
         {
             // We don't hold onto any resources so there is nothing to be done.
         }
 
         public Object clone() throws CloneNotSupportedException
         {
             throw new CloneNotSupportedException();
         }
     }
 }