/**
    * This file Copyright (c) 2017-2018 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.module.cache.ehcache3;
  
  import info.magnolia.module.cache.BlockingCache;
  import info.magnolia.module.cache.CacheModule;
  import info.magnolia.module.cache.blocking.AbstractBlockingCache;
  import info.magnolia.module.cache.filter.CachedEntry;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import javax.servlet.FilterChain;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.ehcache.Cache;
  import org.ehcache.Status;
  import org.ehcache.UserManagedCache;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Magnolia cache wrapper for underlying ehCache3 implementation.
   */
  public class EhCache3Wrapper extends AbstractBlockingCache implements BlockingCache {
  
      private static final Logger log = LoggerFactory.getLogger(EhCache3Wrapper.class);
  
      private final Cache ehcache;
  
      public EhCache3Wrapper(String name, CacheModule cacheModule, int blockingTimeout, Cache ehcache) {
          super(name, cacheModule, blockingTimeout);
          this.ehcache = ehcache;
      }
  
      @Override
      public Object getQuiet(Object key) {
          if (isInitialized()) {
              super.getQuiet(key);
              final Object value = ehcache.get(key);
              return value instanceof CacheEntryTtlWrapper ? ((CacheEntryTtlWrapper) value).getWrappedValue() : value;
          } else {
              return null;
          }
      }
  
      @Override
      protected void putQuiet(Object key, Object value, int timeToLiveInSeconds) {
          if (isInitialized()) {
              if (timeToLiveInSeconds != -1 && !(value instanceof CachedEntry)) { //need to specify TTL if it's not -1 or TTL is not stored in the value
                  value = new CacheEntryTtlWrapper(value, timeToLiveInSeconds);
              }
              ehcache.put(key, value);
          }
      }
  
      private static class CacheEntryTtlWrapper implements CachedEntry {
  
          final Object wrapped;
          final int ttl;
  
          private CacheEntryTtlWrapper(Object wrapped, int ttl) {
              this.wrapped = wrapped;
              this.ttl = ttl;
         }
 
         @Override
         public void replay(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
             throw new UnsupportedOperationException();
         }
 
         @Override
         public String getOriginalURL() {
             throw new UnsupportedOperationException();
         }
 
         @Override
         public long getLastModificationTime() {
             throw new UnsupportedOperationException();
         }
 
         @Override
         public int getTimeToLiveInSeconds() {
             return ttl;
         }
 
         private Object getWrappedValue() {
             return wrapped;
         }
     }
 
     @Override
     public void remove(Object key) {
         if (isInitialized()) {
             ehcache.remove(key);
             super.remove(key);
         }
     }
 
     @Override
     public void clear() {
         if (isInitialized()) {
             ehcache.clear();
             super.clear();
         }
     }
 
     @Override
     public int getSize() {
         if (!isInitialized()) {
             return 0;
         }
         final Iterator iterator = ehcache.iterator();
         int size = 0;
         while(iterator.hasNext()) {
             iterator.next();
             size++;
         }
         return size;
     }
 
     @Override
     public List<Object> getKeys() {
         if (!isInitialized()) {
             return new ArrayList<>();
         }
         final Iterator<Cache.Entry> iterator = ehcache.iterator();
         final List<Object> keys = new ArrayList<>();
         while(iterator.hasNext()) {
             Cache.Entry entry = iterator.next();
             keys.add(entry.getKey());
         }
         return keys;
     }
 
     public Cache getWrappedEhCache() {
         return ehcache;
     }
 
     private boolean isInitialized() {
         if  (ehcache instanceof UserManagedCache && ((UserManagedCache) ehcache).getStatus() == Status.UNINITIALIZED) {
             log.warn("Cache named {{}} is {}. Ignoring any calls on it. This might happen when editing the Ehcache factory configuration at runtime", getName(), Status.UNINITIALIZED);
             return false;
         } else {
             return true;
         }
     }
 }