/**
    * This file Copyright (c) 2003-2014 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.admininterface;
  
  import info.magnolia.cms.beans.config.ObservedManager;
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.util.ContentUtil;
  import info.magnolia.cms.util.SystemContentWrapper;
  import info.magnolia.cms.util.NodeDataUtil;
  import info.magnolia.content2bean.Content2BeanException;
  import info.magnolia.content2bean.Content2BeanUtil;
  import info.magnolia.content2bean.TransformationState;
  import info.magnolia.content2bean.impl.Content2BeanTransformerImpl;
  import info.magnolia.objectfactory.ComponentProvider;
  import info.magnolia.objectfactory.Components;
  
  import java.lang.reflect.Constructor;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  import javax.inject.Singleton;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.beanutils.BeanUtils;
  import org.apache.commons.beanutils.ConstructorUtils;
  
  
  /**
   * Manages the page handlers. A page is a very simple dialog without any configuration.
   * @author philipp
   */
  @Singleton
  public class PageHandlerManager extends ObservedManager {
  
      /**
       * The handlers
       */
      private final Map dialogPageHandlers = new HashMap();
  
      /**
       * Find a handler by name
       * @param name
       * @param request
       * @param response
       * @return an instance of the handlers
       */
      public PageMVCHandler getPageHandler(String name, HttpServletRequest request, HttpServletResponse response) {
  
          PageDefinition pageDefinition = (PageDefinition) dialogPageHandlers.get(name);
  
          if (pageDefinition == null) {
              log.warn("Page definition not found: \"{}\"", name);
              return null;
          }
          return pageDefinition.newInstance(name, request, response);
      }
  
      /**
       * register the pages from the config
       * @param defNode
       */
      @Override
      protected void onRegister(Content defNode) {
          // read the dialog configuration
  
          for (Iterator iter = ContentUtil.getAllChildren(defNode).iterator(); iter.hasNext();) {
             Content pageNode = (Content) iter.next();
 
             PageDefinition pd = new RepositoryPageDefinition(new SystemContentWrapper(pageNode));
             registerPageDefinition(pd);
         }
 
     }
 
     public void registerPageDefinition(PageDefinition pageDefinition) {
         dialogPageHandlers.put(pageDefinition.getName(), pageDefinition);
     }
 
     /**
      * @deprecated
      */
     public void registerPageDefinition(String name, PageDefinition pageDefinition) {
         dialogPageHandlers.put(name, pageDefinition);
     }
 
     /**
      * @return Returns the instance.
      */
     public static PageHandlerManager getInstance() {
         return Components.getSingleton(PageHandlerManager.class);
     }
 
     @Override
     protected void onClear() {
         this.dialogPageHandlers.clear();
     }
 
     public static interface PageDefinition {
 
         public String getName();
 
         public PageMVCHandler newInstance(String name, HttpServletRequest request, HttpServletResponse response);
     }
 
     /**
      * This class is used if you want to register a page that is not stored in the repository.
      * @author philipp
      * @version $Id$
      */
     public static class BasePageDefinition implements PageDefinition {
         private final static org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(BasePageDefinition.class);
 
         private Map defaultProperties = new HashMap();
 
         private Class handlerClass;
 
         private String name;
 
         public BasePageDefinition(String name, Class handlerClass) {
             this.name = name;
             this.handlerClass = handlerClass;
         }
 
         public Map getDefaultProperties() {
             return this.defaultProperties;
         }
 
         public void setDefaultProperties(Map defaultProperties) {
             this.defaultProperties = defaultProperties;
         }
 
         public Class getHandlerClass() {
             return this.handlerClass;
         }
 
         public void setHandlerClass(Class handlerClass) {
             this.handlerClass = handlerClass;
         }
 
         @Override
         public String getName() {
             return this.name;
         }
 
         public void setName(String name) {
             this.name = name;
         }
 
         @Override
         public PageMVCHandler newInstance(String name, HttpServletRequest request, HttpServletResponse response) {
 
             try {
                 Constructor constructor = getHandlerClass().getConstructor(
                     new Class[]{String.class, HttpServletRequest.class, HttpServletResponse.class});
                 PageMVCHandler page = (PageMVCHandler) constructor.newInstance(new Object[]{name, request, response});
                 BeanUtils.populate(page, getDefaultProperties());
                 return page;
             }
             catch (Exception e) {
                 log.error("Can't instantiate page [" + name + "]", e);
                 throw new InvalidDialogPageHandlerException(name, e);
             }
 
         }
     }
 
     public static class RepositoryPageDefinition implements PageDefinition {
 
         private Content node;
 
         public RepositoryPageDefinition(Content node) {
             this.node = node;
         }
 
         @Override
         public String getName() {
             return NodeDataUtil.getString(this.node, "name", this.node.getName());
         }
 
         @Override
         public PageMVCHandler newInstance(String name, final HttpServletRequest request,
             final HttpServletResponse response) {
             try {
                 return (PageMVCHandler) Content2BeanUtil.toBean(node, true, new Content2BeanTransformerImpl() {
 
                     @Override
                     public Object newBeanInstance(TransformationState state, Map properties, ComponentProvider componentProvider)
                         throws Content2BeanException {
                         if (state.getLevel() == 1) {
                             try {
                                 // TODO - with ioc and a request-scope container, this can go away \o/
                                 return ConstructorUtils.invokeConstructor(
                                     state.getCurrentType().getType(),
                                     new Object[]{getName(), request, response});
                             }
                             catch (Exception e) {
                                 throw new Content2BeanException("no proper constructor found", e);
                             }
                         }
 
                         return super.newBeanInstance(state, properties, componentProvider);
                     }
                 });
             }
             catch (Content2BeanException e) {
                 throw new InvalidDialogPageHandlerException(this.getName(), e);
             }
         }
     }
 
 }