/*
    * 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.push.cdi;
  
  import java.io.Serializable;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.Future;
  import javax.enterprise.inject.spi.BeanManager;
  import javax.enterprise.inject.spi.CDI;
  import javax.faces.FacesException;
  import javax.faces.context.FacesContext;
  import javax.faces.push.PushContext;
  import org.apache.myfaces.cdi.util.CDIUtils;
  
  /**
   *
   */
  public class PushContextImpl implements PushContext
  {
      
      private final String channel;
  
      public PushContextImpl(String channel)
      {
          this.channel = channel;
      }
  
      /**
       * @return the channel
       */
      public String getChannel()
      {
          return channel;
      }
  
      @Override
      public Set<Future<Void>> send(Object message)
      {
          //1. locate the channel and define the context
          String channel = getChannel();
          BeanManager beanManager = null;
          FacesContext facesContext = FacesContext.getCurrentInstance();
          if (facesContext != null)
          {
              beanManager = CDIUtils.getBeanManager(facesContext.getExternalContext());
          }
          else
          {
              beanManager = CDI.current().getBeanManager();
          }
          
          WebsocketApplicationBean appTokenBean = CDIUtils.getInstance(beanManager, 
                  WebsocketApplicationBean.class, false);
          WebsocketViewBean viewTokenBean = null;
          WebsocketSessionBean sessionTokenBean = null;
          
          if (CDIUtils.isSessionScopeActive(beanManager))
          {
              sessionTokenBean = CDIUtils.getInstance(beanManager, WebsocketSessionBean.class, false);
              if (CDIUtils.isViewScopeActive(beanManager))
              {
                  viewTokenBean = CDIUtils.getInstance(beanManager, WebsocketViewBean.class, false);
              }
          }
          
          if (appTokenBean == null)
          {
              // No base bean to push message
              return Collections.emptySet();
          }
          
          List<String> channelTokens;
          
          if (viewTokenBean != null && viewTokenBean.isChannelAvailable(channel))
          {
              // Use view scope for context
              channelTokens = viewTokenBean.getChannelTokensFor(channel);
         }
         else if (sessionTokenBean != null && sessionTokenBean.isChannelAvailable(getChannel()))
         {
             // Use session scope for context
             channelTokens = sessionTokenBean.getChannelTokensFor(channel);
         }
         else if (appTokenBean != null && appTokenBean.isChannelAvailable(getChannel()))
         {
             // Use application scope for context
             channelTokens = appTokenBean.getChannelTokensFor(channel);
         }
         else
         {
             throw new FacesException("CDI bean not found for push message");
         }
         
         //2. send the message
         
         if (channelTokens != null && !channelTokens.isEmpty())
         {
             Set<Future<Void>> result = null;
             for (String channelToken : channelTokens)
             {
                 if (result == null)
                 {
                     result = WebsocketApplicationSessionHolder.send(channelToken, message);
                 }
                 else
                 {
                     result.addAll(WebsocketApplicationSessionHolder.send(channelToken, message));
                 }
             }
             return result;
         }
         
         return Collections.emptySet();
     }
 
     @Override
     public <S extends Serializable> Set<Future<Void>> send(Object message, S user)
     {
         return send(message, Collections.singleton(user)).get(user);
     }
 
     @Override
     public <S extends Serializable> Map<S, Set<Future<Void>>> send(Object message, Collection<S> users)
     {
         //1. locate the channel and define the context
         String channel = getChannel();
         BeanManager beanManager = null;
         FacesContext facesContext = FacesContext.getCurrentInstance();
         if (facesContext != null)
         {
             beanManager = CDIUtils.getBeanManager(facesContext.getExternalContext());
         }
         else
         {
             beanManager = CDI.current().getBeanManager();
         }
         
         WebsocketApplicationBean appTokenBean = CDIUtils.getInstance(beanManager, 
                 WebsocketApplicationBean.class, false);
         WebsocketViewBean viewTokenBean = null;
         WebsocketSessionBean sessionTokenBean = null;
         
         if (CDIUtils.isSessionScopeActive(beanManager))
         {
             sessionTokenBean = CDIUtils.getInstance(beanManager, WebsocketSessionBean.class, false);
             if (CDIUtils.isViewScopeActive(beanManager))
             {
                 viewTokenBean = CDIUtils.getInstance(beanManager, WebsocketViewBean.class, false);
             }
         }
         
         if (appTokenBean == null)
         {
             // No base bean to push message
             return Collections.emptyMap();
         }
 
         Map<S, Set<Future<Void>>> result = new HashMap<S, Set<Future<Void>>>();
         
         if (viewTokenBean != null && viewTokenBean.isChannelAvailable(channel))
         {
             // Use view scope for context
             for (S user : users)
             {
                 result.put(user, send(viewTokenBean.getChannelTokensFor(channel, user), message));
             }
         }
         else if (sessionTokenBean != null && sessionTokenBean.isChannelAvailable(getChannel()))
         {
             // Use session scope for context
             for (S user : users)
             {
                 result.put(user, send(sessionTokenBean.getChannelTokensFor(channel, user), message));
             }
         }
         else if (appTokenBean != null && appTokenBean.isChannelAvailable(getChannel()))
         {
             // Use application scope for context
             for (S user : users)
             {
                 result.put(user, send(appTokenBean.getChannelTokensFor(channel, user), message));
             }
         }
         else
         {
             throw new FacesException("CDI bean not found for push message");
         }
         
         //2. send the message
         return result;
     }
     
     private Set<Future<Void>> send(
             List<String> channelTokens, Object message)
     {
         if (channelTokens != null && !channelTokens.isEmpty())
         {
             Set<Future<Void>> result = null;
             for (int i = 0; i < channelTokens.size(); i++)
             {
                 String channelToken = channelTokens.get(i);
                 if (result == null)
                 {
                     result = WebsocketApplicationSessionHolder.send(channelToken, message);
                 }
                 else
                 {
                     result.addAll(WebsocketApplicationSessionHolder.send(channelToken, message));
                 }
             }
             return result;
         }
         return Collections.emptySet();
     }
 }