/**
 * 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.groovyscript.text;

import groovy.lang.Writable;
import groovy.text.Template;

import org.exoplatform.commons.cache.future.FutureCache;
import org.exoplatform.commons.cache.future.FutureExoCache;
import org.exoplatform.commons.cache.future.Loader;
import org.exoplatform.commons.utils.IOUtil;
import org.exoplatform.groovyscript.GroovyTemplate;
import org.exoplatform.groovyscript.GroovyTemplateEngine;
import org.exoplatform.management.annotations.Impact;
import org.exoplatform.management.annotations.ImpactType;
import org.exoplatform.management.annotations.Managed;
import org.exoplatform.management.annotations.ManagedDescription;
import org.exoplatform.management.annotations.ManagedName;
import org.exoplatform.management.jmx.annotations.NameTemplate;
import org.exoplatform.management.jmx.annotations.Property;
import org.exoplatform.management.rest.annotations.RESTEndpoint;
import org.exoplatform.resolver.ResourceKey;
import org.exoplatform.resolver.ResourceResolver;
import org.exoplatform.services.cache.CacheService;
import org.exoplatform.services.cache.ExoCache;
import org.gatein.common.io.IOTools;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.Locale;

/**
 * Created by The eXo Platform SAS Dec 26, 2005
 */
@Managed
@NameTemplate({@Property(key = "view", value = "portal"), @Property(key = "service", value = "management"),
   @Property(key = "type", value = "template")})
@ManagedDescription("Template management service")
@RESTEndpoint(path = "templateservice")
public class TemplateService
{

   private GroovyTemplateEngine engine_;

   private ExoCache<ResourceKey, GroovyTemplate> templatesCache_;

   private TemplateStatisticService statisticService;

   private boolean cacheTemplate_ = true;

   private final Loader<ResourceKey, GroovyTemplate, ResourceResolver> loader = new Loader<ResourceKey, GroovyTemplate, ResourceResolver>()
   {
      public GroovyTemplate retrieve(ResourceResolver context, ResourceKey key) throws Exception
      {
         byte[] bytes;
         InputStream is = context.getInputStream(key.getURL());
         try
         {
            bytes = IOUtil.getStreamContentAsBytes(is);
            is.close();
         }
         finally
         {
            IOTools.safeClose(is);
         }

         // The template class name
         int pos = key.getURL().lastIndexOf('/');
         if (pos == -1)
         {
            pos = 0;
         }
         String name = key.getURL().substring(pos);

         // Julien: it's a bit dangerious here, with respect to the file encoding...
         String text = new String(bytes);

         // Finally do the expensive template creation
         return engine_.createTemplate(key.getURL(), name, text);
      }
   };

   private FutureCache<ResourceKey, GroovyTemplate, ResourceResolver> futureCache;

   public TemplateService(TemplateStatisticService statisticService, CacheService cservice) throws Exception
   {
      this.engine_ = new GroovyTemplateEngine();
      this.statisticService = statisticService;
      this.templatesCache_ = cservice.getCacheInstance(TemplateService.class.getSimpleName());
      this.futureCache = new FutureExoCache<ResourceKey, GroovyTemplate, ResourceResolver>(loader, templatesCache_);
   }

   public void merge(String name, BindingContext context) throws Exception
   {
      long startTime = System.currentTimeMillis();

      GroovyTemplate template = getTemplate(name, context.getResourceResolver());
      context.put("_ctx", context);
      context.setGroovyTemplateService(this);
      template.render(context.getWriter(), context, (Locale)context.get("locale"));
      long endTime = System.currentTimeMillis();

      TemplateStatistic templateStatistic = statisticService.getTemplateStatistic(name);
      templateStatistic.setTime(endTime - startTime);
      templateStatistic.setResolver(context.getResourceResolver());
   }

   @Deprecated
   public void merge(Template template, BindingContext context) throws Exception
   {
      context.put("_ctx", context);
      context.setGroovyTemplateService(this);
      Writable writable = template.make(context);
      writable.writeTo(context.getWriter());
   }

   public void include(String name, BindingContext context) throws Exception
   {
      if (context == null)
         throw new Exception("Binding cannot be null");
      context.put("_ctx", context);
      GroovyTemplate template = getTemplate(name, context.getResourceResolver());
      template.render(context.getWriter(), context, (Locale)context.get("locale"));
   }

   final public GroovyTemplate getTemplate(String name, ResourceResolver resolver) throws Exception
   {
      return getTemplate(name, resolver, cacheTemplate_);
   }

   final public GroovyTemplate getTemplate(String url, ResourceResolver resolver, boolean cacheable) throws Exception
   {
      GroovyTemplate template;
      ResourceKey resourceId = resolver.createResourceKey(url);
      if (cacheable)
      {
         template = futureCache.get(resolver, resourceId);
      }
      else
      {
         template = loader.retrieve(resolver, resourceId);
      }

      //
      return template;
   }

   final public void invalidateTemplate(String name, ResourceResolver resolver) throws Exception
   {
      ResourceKey resourceKey = resolver.createResourceKey(name);
      getTemplatesCache().remove(resourceKey);
   }

   public ExoCache<ResourceKey, GroovyTemplate> getTemplatesCache()
   {
      return templatesCache_;
   }

   /*
    * Clear the templates cache
    */
   @Managed
   @ManagedDescription("Clear the template cache")
   public void reloadTemplates()
   {
      try
      {
         templatesCache_.clearCache();
      }
      catch (Exception e)
      {
         e.printStackTrace();
      }
   }

   /*
    * Clear the template cache by name
    */
   @Managed
   @ManagedDescription("Clear the template cache for a specified template identifier")
   @Impact(ImpactType.IDEMPOTENT_WRITE)
   public void reloadTemplate(@ManagedDescription("The template id") @ManagedName("templateId") String name)
   {
      try
      {
         TemplateStatistic app = statisticService.apps.get(name);
         if(app != null)
         {
            ResourceResolver resolver = app.getResolver();
            templatesCache_.remove(resolver.createResourceKey(name));
         }
      }
      catch (Exception e)
      {
         e.printStackTrace();
      }
   }

   @Managed
   @ManagedDescription("List the identifiers of the cached templates")
   @Impact(ImpactType.READ)
   public String[] listCachedTemplates()
   {
      try
      {
         ArrayList<String> list = new ArrayList<String>();
         for (GroovyTemplate template : templatesCache_.getCachedObjects())
         {
            list.add(template.getId());
         }
         return list.toArray(new String[list.size()]);
      }
      catch (Exception e)
      {
         e.printStackTrace();
         return null;
      }
   }
}
