/*
    * 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.flow.cdi;
  
  import java.lang.annotation.Annotation;
  import java.util.List;
  import java.util.Map;
  import javax.enterprise.context.ContextNotActiveException;
  import javax.enterprise.context.spi.Context;
  import javax.enterprise.context.spi.Contextual;
  import javax.enterprise.context.spi.CreationalContext;
  import javax.enterprise.inject.Typed;
  import javax.enterprise.inject.spi.Bean;
  import javax.enterprise.inject.spi.BeanManager;
  import javax.enterprise.inject.spi.PassivationCapable;
  import javax.faces.context.FacesContext;
  import javax.faces.flow.Flow;
  import javax.faces.flow.FlowHandler;
  import javax.faces.flow.FlowScoped;
  import org.apache.myfaces.cdi.util.BeanProvider;
  import org.apache.myfaces.cdi.util.ContextualInstanceInfo;
  import org.apache.myfaces.cdi.util.ContextualStorage;
  import org.apache.myfaces.flow.FlowReference;
  import org.apache.myfaces.flow.util.FlowUtils;
  
  /**
   * Minimal implementation of FlowScope.
   * 
   * @TODO: We need something better for this part. The problem is the beans
   * are just put under the session map using the old know SubKeyMap hack used
   * in Flash object, but CDI implementations like OWB solves the passivation
   * problem better. The ideal is provide a myfaces specific SPI interface, to
   * allow provide custom implementation of this detail.
   * 
   * @TODO: FlowHandler.transition() method should call this object when the
   * user enter or exit a flow.
   *
   * @author Leonardo Uribe
   */
  @Typed()
  public class FlowScopedContextImpl implements Context
  {
      /**
       * Whether the Context is for a passivating scope.
       */
      private final boolean passivatingScope;
  
      /**
       * needed for serialisation and passivationId
       */
      private BeanManager beanManager;
      
      private Map<Class, FlowReference> flowBeanReferences;
  
      //private FlowScopeBeanHolder flowScopeBeanHolder;
      
      public FlowScopedContextImpl(BeanManager beanManager, 
          Map<Class, FlowReference> flowBeanReferences)
      {
          this.beanManager = beanManager;
          this.flowBeanReferences = flowBeanReferences;
          passivatingScope = beanManager.isPassivatingScope(getScope());
      }
      
      /*
      public void initFlowContext(FlowScopeBeanHolder flowScopeBeanHolder)
      {
          this.flowScopeBeanHolder = flowScopeBeanHolder;
      }*/
      
      protected FlowScopeBeanHolder getFlowScopeBeanHolder()
      {
          return getFlowScopeBeanHolder(FacesContext.getCurrentInstance());
      }
      
      protected FlowScopeBeanHolder getFlowScopeBeanHolder(FacesContext facesContext)
      {
          FlowScopeBeanHolder flowScopeBeanHolder = (FlowScopeBeanHolder) 
              facesContext.getExternalContext().getApplicationMap().get(
                  "oam.flow.FlowScopeBeanHolder");
          if (flowScopeBeanHolder == null)
          {
              flowScopeBeanHolder = BeanProvider.getContextualReference(
                 beanManager, FlowScopeBeanHolder.class, false);
             facesContext.getExternalContext().getApplicationMap().put(
                 "oam.flow.FlowScopeBeanHolder", flowScopeBeanHolder);
         }
         return flowScopeBeanHolder;
     }
     
     public String getCurrentClientWindowFlowId(FacesContext facesContext)
     {
         String flowMapKey = null;
         FlowHandler flowHandler = facesContext.getApplication().getFlowHandler();
         Flow flow = flowHandler.getCurrentFlow(facesContext);
         if (flow != null)
         {
             flowMapKey = FlowUtils.getFlowMapKey(facesContext, flow);
         }
         return flowMapKey;
     }
 
     /**
      * An implementation has to return the underlying storage which
      * contains the items held in the Context.
      * @param createIfNotExist whether a ContextualStorage shall get created if it doesn't yet exist.
      * @return the underlying storage
      */
     protected ContextualStorage getContextualStorage(boolean createIfNotExist, String clientWindowFlowId)
     {
         //FacesContext facesContext = FacesContext.getCurrentInstance();
         //String clientWindowFlowId = getCurrentClientWindowFlowId(facesContext);
         if (clientWindowFlowId == null)
         {
             throw new ContextNotActiveException("FlowScopedContextImpl: no current active flow");
         }
 
         if (createIfNotExist)
         {
             return getFlowScopeBeanHolder().getContextualStorage(beanManager, clientWindowFlowId);
         }
         else
         {
             return getFlowScopeBeanHolder().getContextualStorageNoCreate(beanManager, clientWindowFlowId);
         }
     }
 
     public Class<? extends Annotation> getScope()
     {
         return FlowScoped.class;
     }
 
     public boolean isActive()
     {
         return isActive(FacesContext.getCurrentInstance());
     }
 
     public boolean isActive(FacesContext facesContext)
     {
         if (facesContext == null)
         {
             return false;
         }
         Flow flow = facesContext.getApplication().
             getFlowHandler().getCurrentFlow(facesContext);
         
         return flow != null;
     }
 
     /**
      * @return whether the served scope is a passivating scope
      */
     public boolean isPassivatingScope()
     {
         return passivatingScope;
     }
 
     @Override
     public <T> T get(Contextual<T> bean)
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
 
         checkActive(facesContext);
 
         
         FlowReference reference = flowBeanReferences.get(((Bean)bean).getBeanClass());
         if (reference != null)
         {
             String flowMapKey = FlowUtils.getFlowMapKey(facesContext, reference);
             if (flowMapKey != null)
             {
                 ContextualStorage storage = getContextualStorage(false, flowMapKey);
                 if (storage != null)
                 {
                     Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
                     ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));
 
                     if (contextualInstanceInfo != null)
                     {
                         return (T) contextualInstanceInfo.getContextualInstance();
                     }
                 }
             }
             else
             {
                 throw new IllegalStateException("Flow "+ reference.getId()+
                     " cannot be found when resolving bean " +bean.toString());
             }
         }
         
         List<String> activeFlowMapKeys = getFlowScopeBeanHolder().getActiveFlowMapKeys(facesContext);
         for (String flowMapKey : activeFlowMapKeys)
         {
             ContextualStorage storage = getContextualStorage(false, flowMapKey);
             if (storage == null)
             {
                 //return null;
                 continue;
             }
 
             Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
             ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));
             if (contextualInstanceInfo == null)
             {
                 //return null;
                 continue;
             }
 
             return (T) contextualInstanceInfo.getContextualInstance();
         }
         return null;
     }
 
     @Override
     public <T> T get(Contextual<T> bean, CreationalContext<T> creationalContext)
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
         
         checkActive(facesContext);
 
         if (passivatingScope && !(bean instanceof PassivationCapable))
         {
             throw new IllegalStateException(bean.toString() +
                     " doesn't implement " + PassivationCapable.class.getName());
         }
         
         FlowReference reference = flowBeanReferences.get(((Bean)bean).getBeanClass());
         if (reference != null)
         {
             String flowMapKey = FlowUtils.getFlowMapKey(facesContext, reference);
             if (flowMapKey != null)
             {
                 ContextualStorage storage = getContextualStorage(false, flowMapKey);
                 if (storage != null)
                 {
                     Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
                     ContextualInstanceInfo<?> contextualInstanceInfo = contextMap.get(storage.getBeanKey(bean));
 
                     if (contextualInstanceInfo != null)
                     {
                         return (T) contextualInstanceInfo.getContextualInstance();
                     }
                 }
             }
             else
             {
                 throw new IllegalStateException("Flow "+ reference.getId()+
                     " cannot be found when resolving bean " + bean.toString());
             }
             
             FlowHandler flowHandler = facesContext.getApplication().getFlowHandler();
             // Since it is possible to have only the flow id without documentId, the best
             // is first get the flow using flowHandler.getFlow and then check if the flow is
             // active or not, but using the documentId and id of the retrieved flow.
             Flow flow = flowHandler.getFlow(facesContext, 
                 reference.getDocumentId() == null ? "" : reference.getDocumentId(), reference.getId());
             if (flow == null)
             {
                 throw new IllegalStateException(bean.toString() + "cannot be created because flow "+ reference.getId()+
                     " is not registered");
             }
             if (!flowHandler.isActive(facesContext, flow.getDefiningDocumentId(), flow.getId())) 
             {
                 throw new IllegalStateException(bean.toString() + "cannot be created if flow "+ reference.getId()+
                     " is not active");
             }
             
             ContextualStorage storage = getContextualStorage(true, flowMapKey);
             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);
         }
 
         List<String> activeFlowMapKeys = getFlowScopeBeanHolder().getActiveFlowMapKeys(facesContext);
         for (String flowMapKey : activeFlowMapKeys)
         {
             ContextualStorage storage = getContextualStorage(false, flowMapKey);
 
             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;
                 }
             }
 
         }
         
         ContextualStorage storage = getContextualStorage(true, getCurrentClientWindowFlowId(facesContext));
         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)
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
         List<String> activeFlowMapKeys = getFlowScopeBeanHolder().getActiveFlowMapKeys(facesContext);
         for (String flowMapKey : activeFlowMapKeys)
         {
             ContextualStorage storage = getContextualStorage(false, flowMapKey);
             if (storage == null)
             {
                 //return false;
                 continue;
             }
             ContextualInstanceInfo<?> contextualInstanceInfo = storage.getStorage().get(storage.getBeanKey(bean));
 
             if (contextualInstanceInfo == null)
             {
                 //return false;
                 continue;
             }
 
             bean.destroy(contextualInstanceInfo.getContextualInstance(), contextualInstanceInfo.getCreationalContext());
             return true;
         }
         return false;
     }
 
     /**
      * destroys all the Contextual Instances in the Storage returned by
      * {@link #getContextualStorage(boolean)}.
      */
     /*
     public void destroyAllActive()
     {
         ContextualStorage storage = getContextualStorage(false);
         if (storage == null)
         {
             return;
         }
 
         destroyAllActive(storage);
     }*/
 
     /**
      * Destroys all the Contextual Instances in the specified ContextualStorage.
      * This is a static method to allow various holder objects to cleanup
      * properly in &#064;PreDestroy.
      */
     public static void destroyAllActive(ContextualStorage storage)
     {
         Map<Object, ContextualInstanceInfo<?>> contextMap = storage.getStorage();
         for (Map.Entry<Object, ContextualInstanceInfo<?>> entry : contextMap.entrySet())
         {
             if (!FlowScopeBeanHolder.CURRENT_FLOW_SCOPE_MAP.equals(entry.getKey()))
             {
                 Contextual bean = storage.getBean(entry.getKey());
 
                 ContextualInstanceInfo<?> contextualInstanceInfo = entry.getValue();
                 bean.destroy(contextualInstanceInfo.getContextualInstance(), 
                     contextualInstanceInfo.getCreationalContext());
             }
         }
     }
 
     /**
      * Make sure that the Context is really active.
      * @throws ContextNotActiveException if there is no active
      *         Context for the current Thread.
      */
     protected void checkActive(FacesContext facesContext)
     {
         if (!isActive(facesContext))
         {
             throw new ContextNotActiveException("CDI context with scope annotation @"
                 + getScope().getName() + " is not active with respect to the current thread");
         }
     }
 
 }