/*
    * 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.util;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Type;
  import java.util.Collections;
  import java.util.Set;
  import javax.enterprise.context.ContextNotActiveException;
  import javax.enterprise.context.SessionScoped;
  import javax.enterprise.context.spi.Context;
  
  import javax.enterprise.context.spi.CreationalContext;
  import javax.enterprise.inject.spi.Bean;
  import javax.enterprise.inject.spi.BeanManager;
  import javax.faces.context.ExternalContext;
  import javax.faces.view.ViewScoped;
  import org.apache.myfaces.webapp.AbstractFacesInitializer;
  
  /**
   * Lookup code for Contextual Instances.
   */
  public class CDIUtils
  {
      public static BeanManager getBeanManager(ExternalContext externalContext)
      {
          return (BeanManager) externalContext.getApplicationMap().get(
              AbstractFacesInitializer.CDI_BEAN_MANAGER_INSTANCE);
      }
  
  
  
      public static <T> T lookup(BeanManager bm, Class<T> clazz)
      {
          Set<Bean<?>> beans = bm.getBeans(clazz);
          return resolveInstance(bm, beans, clazz);
      }
  
      public static Object lookup(BeanManager bm, String name)
      {
          Set<Bean<?>> beans = bm.getBeans(name);
          return resolveInstance(bm, beans, Object.class);
      }
  
      private static <T> T resolveInstance(BeanManager bm, Set<Bean<?>> beans, Type type)
      {
          Bean<?> bean = bm.resolve(beans);
          CreationalContext<?> cc = bm.createCreationalContext(bean);
          T dao = (T) bm.getReference(bean, type, cc);
          return dao;
  
      }
      
      @SuppressWarnings("unchecked")
      public static <T> Bean<T> resolve(BeanManager beanManager, Class<T> beanClass, Annotation... qualifiers)
      {
          Set<Bean<?>> beans = beanManager.getBeans(beanClass, qualifiers);
  
          for (Bean<?> bean : beans)
          {
              if (bean.getBeanClass() == beanClass)
              {
                  return (Bean<T>) beanManager.resolve(Collections.<Bean<?>>singleton(bean));
              }
          }
  
          return (Bean<T>) beanManager.resolve(beans);
      }
  
      @SuppressWarnings("unchecked")
      public static <T> Bean<T> resolve(BeanManager beanManager, Type type, Annotation... qualifiers)
      {
          Set<Bean<?>> beans = beanManager.getBeans(type, qualifiers);
  
          return (Bean<T>) beanManager.resolve(beans);
      }
  
      public static <T> T getInstance(BeanManager beanManager, Class<T> beanClass, 
              boolean create, Annotation... qualifiers)
      {
          try
          {
              Bean<T> bean = resolve(beanManager, beanClass, qualifiers);
             return (bean != null) ? getInstance(beanManager, bean, create) : null;
         }
         catch (ContextNotActiveException e)
         {
             return null;
         }
     }
 
     public static <T> T getInstance(BeanManager beanManager, Type type, 
     boolean create, Annotation... qualifiers)
     {
         try
         {
             Bean<T> bean = resolve(beanManager, type, qualifiers);
             return (bean != null) ? getInstance(beanManager, bean, create) : null;
         }
         catch (ContextNotActiveException e)
         {
             return null;
         }
     }
 
     public static <T> T getInstance(BeanManager beanManager, Bean<T> bean, boolean create)
     {
         Context context = beanManager.getContext(bean.getScope());
 
         if (create)
         {
             return context.get(bean, beanManager.createCreationalContext(bean));
         }
         else
         {
             return context.get(bean);
         }
     }
     
     public static boolean isSessionScopeActive(BeanManager beanManager)
     {
         try 
         {
             Context ctx = beanManager.getContext(SessionScoped.class);
             return ctx != null;
         }
         catch (ContextNotActiveException ex)
         {
             //No op
         }
         catch (Exception ex)
         {
             // Sometimes on startup time, since there is no active request context, trying to grab session scope
             // throws NullPointerException.
             //No op
         }
         return false;
     }
     
     public static boolean isViewScopeActive(BeanManager beanManager)
     {
         try 
         {
             Context ctx = beanManager.getContext(ViewScoped.class);
             return ctx != null;
         }
         catch (ContextNotActiveException ex)
         {
             //No op
         }
         catch (Exception ex)
         {
             // Sometimes on startup time, since there is no active request context, trying to grab session scope
             // throws NullPointerException.
             //No op
         }
         return false;
     }
         
 }