/**
    * This file Copyright (c) 2003-2011 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.templating;
  
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.core.ItemType;
  import info.magnolia.cms.beans.config.ObservedManager;
  import info.magnolia.objectfactory.Classes;
  import info.magnolia.objectfactory.Components;
  import info.magnolia.objectfactory.MgnlInstantiationException;
  import org.apache.commons.lang.StringUtils;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.Map;
  
  /**
   * Manages the paragraph renderers on the system. Modules can register the nodes where
   * the paragraph renderers are defined.
   * @author gjoseph
   * @version $Revision: $ ($Author: $)
   */
  public class ParagraphRendererManager extends ObservedManager {
  
      public static ParagraphRendererManager getInstance() {
          return Components.getSingleton(ParagraphRendererManager.class);
      }
  
      private final Map paragraphRenderers;
  
      public ParagraphRendererManager() {
          paragraphRenderers = Collections.synchronizedMap(new LinkedHashMap());
      }
  
      public ParagraphRenderer getRenderer(String name) {
          final ParagraphRenderer renderer = (ParagraphRenderer) paragraphRenderers.get(name);
          if (renderer == null) {
              throw new IllegalArgumentException("No paragraph renderer registered with name " + name);
          }
          return renderer;
      }
  
      // TODO : this should allow util pages to get info about the renderer's nodes path and configuration instead of the renderers' impls.
      public Map getRenderers() {
          return paragraphRenderers;
      }
  
      protected void onRegister(Content node) {
          final Collection list = node.getChildren(ItemType.CONTENTNODE);
          final Iterator it = list.iterator();
          while (it.hasNext()) {
              final Content paragraphRendererNode = (Content) it.next();
              String name = paragraphRendererNode.getNodeData("name").getString();
              String clazz = paragraphRendererNode.getNodeData("class").getString();
  
              if (StringUtils.isEmpty(name)) {
                  name = paragraphRendererNode.getName();
              }
  
              if (StringUtils.isBlank(name) || StringUtils.isBlank(clazz)) {
                  log.warn("Can't register template renderer at {}, missing name or class property.", paragraphRendererNode.getHandle());
                  continue;
              }
  
              try {
                  final ParagraphRenderer renderer = Classes.newInstance(clazz);
                 registererParagraphRenderer(name, renderer);
                 log.debug("Registered template render [{}] with name {}.", clazz, name);
             } catch (MgnlInstantiationException e) {
                 throw newInstanciationException(name, clazz, e);
             } catch (ClassNotFoundException e) {
                 throw newInstanciationException(name, clazz, e);
             }
         }
     }
 
     protected void registererParagraphRenderer(String name, ParagraphRenderer renderer) {
         if (paragraphRenderers.containsKey(name)) {
             throw new IllegalStateException("Duplicate paragraph name \"" + name + "\"");
         }
         paragraphRenderers.put(name, renderer);
     }
 
     protected void onClear() {
         paragraphRenderers.clear();
     }
 
     private IllegalStateException newInstanciationException(String name, String clazz, Exception e) {
         return new IllegalStateException("Can't register paragraph renderer with name [" + name + "] and class [" + clazz + "] : " + e.getClass().getName() + " : " + e.getMessage());
     }
 }