/*
    * 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.view;
  
  import javax.enterprise.context.ContextNotActiveException;
  import javax.enterprise.inject.Typed;
  import javax.enterprise.inject.spi.BeanManager;
  
  import java.lang.annotation.Annotation;
  import java.util.Map;
  import javax.enterprise.context.spi.Context;
  import javax.enterprise.context.spi.Contextual;
  import javax.enterprise.context.spi.CreationalContext;
  import javax.enterprise.inject.spi.PassivationCapable;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.faces.view.ViewScoped;
  
  import org.apache.myfaces.cdi.util.BeanProvider;
  import org.apache.myfaces.cdi.util.ContextualInstanceInfo;
  import org.apache.myfaces.config.ManagedBeanDestroyer;
  import org.apache.myfaces.config.RuntimeConfig;
  import org.apache.myfaces.config.annotation.LifecycleProvider;
  import org.apache.myfaces.config.annotation.LifecycleProviderFactory;
  import org.apache.myfaces.view.ViewScopeProxyMap;
  
  /**
   * CDI Context to handle @{@link ViewScoped} beans.
   * 
   * @author Leonardo Uribe
   */
  @Typed()
  public class ViewScopeContextImpl implements Context
  {
  
      /**
       * needed for serialisation and passivationId
       */
      private BeanManager beanManager;
  
  
      public ViewScopeContextImpl(BeanManager beanManager)
      {
          this.beanManager = beanManager;
      }
  
      protected ViewScopeBeanHolder getViewScopeBeanHolder()
      {
          return getViewScopeBeanHolder(FacesContext.getCurrentInstance());
      }
      
      protected ViewScopeBeanHolder getViewScopeBeanHolder(FacesContext facesContext)
      {
          ViewScopeBeanHolder viewScopeBeanHolder = (ViewScopeBeanHolder) 
              facesContext.getExternalContext().getApplicationMap().get(
                  "oam.view.ViewScopeBeanHolder");
          if (viewScopeBeanHolder == null)
          {
              viewScopeBeanHolder = BeanProvider.getContextualReference(
                  beanManager, ViewScopeBeanHolder.class, false);
              facesContext.getExternalContext().getApplicationMap().put(
                  "oam.view.ViewScopeBeanHolder", viewScopeBeanHolder);
          }
          return viewScopeBeanHolder;
      }
  
      public String getCurrentViewScopeId(boolean create)
      {
          FacesContext facesContext = FacesContext.getCurrentInstance();
          ViewScopeProxyMap map = (ViewScopeProxyMap) facesContext.getViewRoot().getViewMap(create);
          if (map != null)
          {
              String id = map.getViewScopeId();
              if (id == null && create)
              {
                  // Force create
                  map.forceCreateWrappedMap(facesContext);
                  id = map.getViewScopeId();
              }
              return id;
          }
          return null;
      }
 
     protected ViewScopeContextualStorage getContextualStorage(boolean createIfNotExist)
     {
         String viewScopeId = getCurrentViewScopeId(createIfNotExist);
         if (createIfNotExist && viewScopeId == null)
         {
             throw new ContextNotActiveException(
                 "ViewScopeContextImpl: no viewScopeId set for the current view yet!");
         }
         if (viewScopeId != null)
         {
             return getViewScopeBeanHolder().getContextualStorage(beanManager, viewScopeId);
         }
         return null;
     }
 
     public Class<? extends Annotation> getScope()
     {
         return ViewScoped.class;
     }
 
     /**
      * The WindowContext is active once a current windowId is set for the current Thread.
      * @return
      */
     public boolean isActive()
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
         return facesContext.getViewRoot() != null;
     }
 
     public <T> T get(Contextual<T> bean)
     {
         checkActive();
 
         // force session creation if ViewScoped is used
         FacesContext.getCurrentInstance().getExternalContext().getSession(true);
 
         ViewScopeContextualStorage storage = getContextualStorage(false);
         if (storage == null)
         {
             return null;
         }
 
         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
         ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));
         if (contextualInstanceInfo == null)
         {
             return null;
         }
 
         return (T) contextualInstanceInfo.getContextualInstance();
     }
 
     public <T> T get(Contextual<T> bean, CreationalContext<T> creationalContext)
     {
         checkActive();
 
         if (!(bean instanceof PassivationCapable))
         {
             throw new IllegalStateException(bean.toString() +
                     " doesn't implement " + PassivationCapable.class.getName());
         }
 
         // force session creation if ViewScoped is used
         FacesContext.getCurrentInstance().getExternalContext().getSession(true);
 
         ViewScopeContextualStorage storage = getContextualStorage(true);
 
         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
         ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));
 
         if (contextualInstanceInfo != null)
         {
             @SuppressWarnings("unchecked")
             final T instance =  (T) contextualInstanceInfo.getContextualInstance();
 
             if (instance != null)
             {
                 return instance;
             }
         }
 
         return storage.createContextualInstance(bean, creationalContext);
     }
 
     /**
      * Destroy the Contextual Instance of the given Bean.
      * @param bean dictates which bean shall get cleaned up
      * @return <code>true</code> if the bean was destroyed, <code>false</code> if there was no such bean.
      */
     public boolean destroy(Contextual bean)
     {
         ViewScopeContextualStorage storage = getContextualStorage(false);
         if (storage == null)
         {
             return false;
         }
         ContextualInstanceInfo<?> contextualInstanceInfo = 
             storage.getStorage().get(storage.getBeanKey(bean));
 
         if (contextualInstanceInfo == null)
         {
             return false;
         }
 
         bean.destroy(contextualInstanceInfo.getContextualInstance(), 
             contextualInstanceInfo.getCreationalContext());
 
         return true;
     }
 
     /**
      * destroys all the Contextual Instances in the Storage returned by
      * {@link #getContextualStorage(boolean)}.
      */
     public void destroyAllActive()
     {
         ViewScopeContextualStorage storage = getContextualStorage(false);
         if (storage == null)
         {
             return;
         }
 
         destroyAllActive(storage);
     }
 
     public static void destroyAllActive(ViewScopeContextualStorage storage)
     {
         destroyAllActive(storage, FacesContext.getCurrentInstance());
     }
 
     public static void destroyAllActive(ViewScopeContextualStorage storage, FacesContext facesContext)
     {
         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
         ManagedBeanDestroyer mbDestroyer = 
             getManagedBeanDestroyer(facesContext.getExternalContext());
         
         for (Map.Entry<Object, ContextualInstanceInfo<?>> entry : contextMap.entrySet())
         {
             if (!(entry.getKey() instanceof _ContextualKey))
             {            
                 Contextual bean = storage.getBean(facesContext, entry.getKey());
 
                 ContextualInstanceInfo<?> contextualInstanceInfo = entry.getValue();
                 bean.destroy(contextualInstanceInfo.getContextualInstance(), 
                     contextualInstanceInfo.getCreationalContext());
             }
             else
             {
                 // Destroy the JSF managed view scoped bean.
                 _ContextualKey key = (_ContextualKey) entry.getKey();
                 mbDestroyer.destroy(key.getName(), entry.getValue().getContextualInstance());
             }
         }
 
         contextMap.clear();
         
         storage.deactivate();
     }
     
     /**
      * Make sure that the Context is really active.
      * @throws ContextNotActiveException if there is no active
      *         Context for the current Thread.
      */
     protected void checkActive()
     {
         if (!isActive())
         {
             throw new ContextNotActiveException("CDI context with scope annotation @"
                 + getScope().getName() + " is not active with respect to the current thread");
         }
     }
 
     protected static ManagedBeanDestroyer getManagedBeanDestroyer(ExternalContext externalContext)
     {
         RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(externalContext);
         LifecycleProvider lifecycleProvider = LifecycleProviderFactory
                 .getLifecycleProviderFactory(externalContext).getLifecycleProvider(externalContext);
 
         return new ManagedBeanDestroyer(lifecycleProvider, runtimeConfig);
     }
 }