/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.exoplatform.portal.resource.compressor.impl;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.exoplatform.container.component.ComponentPlugin;
import org.exoplatform.container.xml.InitParams;
import org.exoplatform.portal.resource.compressor.ResourceCompressor;
import org.exoplatform.portal.resource.compressor.ResourceCompressorException;
import org.exoplatform.portal.resource.compressor.ResourceCompressorPlugin;
import org.exoplatform.portal.resource.compressor.ResourceType;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;

/**
 * @author <a href="mailto:hoang281283@gmail.com">Minh Hoang TO</a>
 * Aug 19, 2010
 */

public class ResourceCompressorService implements ResourceCompressor
{
   /** . */
   private Log log = ExoLogger.getLogger(ResourceCompressorService.class);

   private Map<ResourceType, List<ResourceCompressorPlugin>> plugins;

   public ResourceCompressorService(InitParams params) throws Exception
   {

      plugins = new HashMap<ResourceType, List<ResourceCompressorPlugin>>();
   }

   public void registerCompressorPlugin(ComponentPlugin plugin)
   {
      if (plugin instanceof ResourceCompressorPlugin)
      {
         ResourceCompressorPlugin compressorPlugin = (ResourceCompressorPlugin)plugin;
         ResourceType type = compressorPlugin.getResourceType();
         List<ResourceCompressorPlugin> sameResourceTypePlugins = plugins.get(type);

         if (sameResourceTypePlugins != null)
         {
            sameResourceTypePlugins.add(compressorPlugin);
            log.debug("Loaded compressor plugin: " + compressorPlugin.getName() + " for resource type "
               + type.toString());
         }
         else
         {
            List<ResourceCompressorPlugin> newListOfPlugins = new ArrayList<ResourceCompressorPlugin>();
            newListOfPlugins.add(compressorPlugin);
            log.debug("Loaded compressor plugin: " + compressorPlugin.getName() + " for new resource type "
               + type.toString());
            plugins.put(type, newListOfPlugins);
         }
      }
   }

   public ResourceCompressorPlugin getCompressorPlugin(ResourceType type, String name)
   {
      List<ResourceCompressorPlugin> sameResourceTypePlugins = plugins.get(type);

      if (sameResourceTypePlugins != null)
      {
         for (ResourceCompressorPlugin plugin : sameResourceTypePlugins)
         {
            if (plugin.getName().equals(name))
            {
               return plugin;
            }
         }
      }
      return null;
   }

   @Override
   final public boolean isSupported(ResourceType resourceType)
   {
      return (getHighestPriorityCompressorPlugin(resourceType) != null);
   }

   @Override
   final public void compress(Reader input, Writer output, ResourceType resourceType)
      throws ResourceCompressorException, IOException
   {
      ResourceCompressorPlugin plugin = getHighestPriorityCompressorPlugin(resourceType);
      if (plugin != null)
      {
         plugin.compress(input, output);
      }
      else
      {
         throw new ResourceCompressorException("There is no compressor for " + resourceType + " type");
      }
   }
   
   @Override
   public String compress(String input, ResourceType resourceType) throws ResourceCompressorException, IOException
   {
      StringReader reader = new StringReader(input);
      StringWriter writer = new StringWriter();
      compress(reader, writer, resourceType);
      return writer.toString();
   }

   public ResourceCompressorPlugin getHighestPriorityCompressorPlugin(ResourceType resourceType)
   {
      List<ResourceCompressorPlugin> candidates = plugins.get(resourceType);
      if (candidates == null || candidates.size() == 0)
      {
         return null;
      }

      //Loop the list instead of invoking sort method
      int highestPriorityIndex = 0;
      int maxPriority = -1;

      for (int i = 0; i < candidates.size(); i++)
      {
         int currentPriority = candidates.get(i).getPriority();
         if (currentPriority > maxPriority)
         {
            highestPriorityIndex = i;
            maxPriority = currentPriority;
         }
      }

      return candidates.get(highestPriorityIndex);
   }
}
