/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.myfaces.cdi.impl;
  
  import java.util.Map;
  import javax.enterprise.inject.spi.BeanManager;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.servlet.ServletContext;
  import org.apache.myfaces.cdi.util.BeanProvider;
  import org.apache.myfaces.cdi.util.CDIUtils;
  import org.apache.myfaces.cdi.JsfApplicationArtifactHolder;
  import org.apache.myfaces.cdi.view.ViewScopeBeanHolder;
  import org.apache.myfaces.cdi.view.ViewScopeCDIMap;
  import org.apache.myfaces.flow.cdi.FlowScopeBeanHolder;
  import org.apache.myfaces.spi.ViewScopeProvider;
  
  /**
   *
   * @author Leonardo Uribe
   */
  public class CDIManagedBeanHandlerImpl extends ViewScopeProvider
  {
      
      private BeanManager beanManager;
      
      private ViewScopeBeanHolder viewScopeBeanHolder;
      
      private FlowScopeBeanHolder flowScopeBeanHolder;
      
      public CDIManagedBeanHandlerImpl()
      {
          ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
          beanManager = CDIUtils.getBeanManager(externalContext);
          Object context = externalContext.getContext();
          if (context instanceof ServletContext)
          {
              JsfApplicationArtifactHolder appBean = CDIUtils.lookup(beanManager, 
                  JsfApplicationArtifactHolder.class);
              appBean.setServletContext((ServletContext) context);
          }
      }
      
      private ViewScopeBeanHolder getViewScopeBeanHolder()
      {
          if (viewScopeBeanHolder == null)
          {
              viewScopeBeanHolder = BeanProvider.getContextualReference(
                  beanManager, ViewScopeBeanHolder.class, false);
          }
          return viewScopeBeanHolder;
      }
      
      private FlowScopeBeanHolder getFlowScopeBeanHolder()
      {
          if (flowScopeBeanHolder == null)
          {
              flowScopeBeanHolder = BeanProvider.getContextualReference(
                  beanManager, FlowScopeBeanHolder.class, false);
          }
          return flowScopeBeanHolder;
      }
      
      public Map<String, Object> createViewScopeMap(FacesContext facesContext, String viewScopeId)
      {
          return new ViewScopeCDIMap(facesContext, viewScopeId);
      }
      
      public Map<String, Object> restoreViewScopeMap(FacesContext facesContext, String viewScopeId)
      {
          return new ViewScopeCDIMap(facesContext, viewScopeId);
      }
      
      public String generateViewScopeId(FacesContext facesContext)
      {
          return getViewScopeBeanHolder().generateUniqueViewScopeId();
      }
      
      /**
       * 
       */
      public void onSessionDestroyed()
      {
         // In CDI case, the best way to deal with this is use a method 
         // with @PreDestroy annotation on a session scope bean 
         // ( ViewScopeBeanHolder.destroyBeans() ). There is no need
         // to do anything else in this location, but it is advised
         // in CDI the beans are destroyed at the end of the request,
         // not when invalidateSession() is called.
         FacesContext facesContext = FacesContext.getCurrentInstance();
         if (facesContext != null)
         {
             if (facesContext.getExternalContext().getSession(false) != null)
             {
                 if (isViewScopeBeanHolderCreated(facesContext))
                 {
                     getViewScopeBeanHolder().destroyBeans();                
                 }
                 if (isFlowScopeBeanHolderCreated(facesContext))
                 {
                     getFlowScopeBeanHolder().destroyBeans();
                 }
             }
         }
     }
     
     private boolean isViewScopeBeanHolderCreated(FacesContext facesContext)
     {
         return facesContext.getExternalContext().
             getSessionMap().containsKey(ViewScopeBeanHolder.VIEW_SCOPE_PREFIX_KEY);
     }
     
     
     private boolean isFlowScopeBeanHolderCreated(FacesContext facesContext)
     {
         return facesContext.getExternalContext().
             getSessionMap().containsKey(FlowScopeBeanHolder.FLOW_SCOPE_PREFIX_KEY);
     }
 
     @Override
     public void destroyViewScopeMap(FacesContext facesContext, String viewScopeId)
     {
         if (facesContext.getExternalContext().getSession(false) != null)
         {
             if (isViewScopeBeanHolderCreated(facesContext))
             {
                 getViewScopeBeanHolder().destroyBeans(viewScopeId);
             }
         }
     }
 }