/*
    * 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.impl;
  
  import java.util.Iterator;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.faces.flow.Flow;
  import org.apache.myfaces.flow.util.FlowUtils;
  import org.apache.myfaces.spi.FacesFlowProvider;
  
  /**
   *
   * @author Leonardo Uribe
   */
  public class DefaultFacesFlowProvider extends FacesFlowProvider
  {
      private static final String FLOW_PREFIX = "oam.flow";
      
      static final String FLOW_SESSION_MAP_SUBKEY_PREFIX = FLOW_PREFIX + ".SCOPE";
      
      /**
       * Token separator.
       */
      static final char SEPARATOR_CHAR = '.';
      
      private final static String CURRENT_FLOW_SCOPE_MAP = "oam.flow.SCOPE_MAP";
  
      @Override
      public Iterator<Flow> getAnnotatedFlows(FacesContext facesContext)
      {
          //Without CDI there is no @FlowDefinition annotations to scan for
          return null;
      }
  
      @Override
      public void doAfterEnterFlow(FacesContext facesContext, Flow flow)
      {
          // Reset current flow scope map
          String mapKey = CURRENT_FLOW_SCOPE_MAP+SEPARATOR_CHAR+
              flow.getDefiningDocumentId()+SEPARATOR_CHAR+flow.getId();        
          facesContext.getAttributes().remove(mapKey);
      }
  
      @Override
      public void doBeforeExitFlow(FacesContext facesContext, Flow flow)
      {
          String flowMapKey = FlowUtils.getFlowMapKey(facesContext, flow);
          String fullToken = FLOW_SESSION_MAP_SUBKEY_PREFIX + SEPARATOR_CHAR + flowMapKey;
  
          String mapKey = CURRENT_FLOW_SCOPE_MAP+SEPARATOR_CHAR+
              flow.getDefiningDocumentId()+SEPARATOR_CHAR+flow.getId();
          Map<Object, Object> map = (Map<Object, Object>) facesContext.getAttributes().get(
              mapKey);
          if (map != null)
          {
              map.clear();
          }
          else
          {
              map = (Map<Object, Object>) facesContext.getExternalContext().
                  getSessionMap().get(fullToken);
              if (map != null)
              {
                  map.clear();
              }
          }
          // Remove the map from session
          facesContext.getExternalContext().getSessionMap().remove(fullToken);
          
          // Reset current flow scope map
          facesContext.getAttributes().remove(mapKey);
      }
  
      @Override
      public Map<Object, Object> getCurrentFlowScope(FacesContext facesContext)
      {
          Flow flow = facesContext.getApplication().getFlowHandler().getCurrentFlow(facesContext);
          Map<Object, Object> map = null;
          if (flow != null)
          {
             String mapKey = CURRENT_FLOW_SCOPE_MAP+SEPARATOR_CHAR+
                 flow.getDefiningDocumentId()+SEPARATOR_CHAR+flow.getId();
             map = (Map<Object, Object>) facesContext.getAttributes().get(mapKey);
             if (map == null)
             {
                 String flowMapKey = FlowUtils.getFlowMapKey(facesContext, flow);
                 
                 //String fullToken = FLOW_SESSION_MAP_SUBKEY_PREFIX + SEPARATOR_CHAR + flowMapKey;
                 //map = createOrRestoreMap(facesContext, fullToken);
                 map = new FlowScopeMap(this, flowMapKey);
                 
                 facesContext.getAttributes().put(mapKey, map);
             }
         }
         return map;
     }
     
     /**
      * Create a new subkey-wrapper of the session map with the given prefix.
      * This wrapper is used to implement the maps for the flash scope.
      * For more information see the SubKeyMap doc.
      */
     Map<Object, Object> createOrRestoreMap(FacesContext context, String prefix,
         boolean create)
     {
         ExternalContext external = context.getExternalContext();
         Map<String, Object> sessionMap = external.getSessionMap();
 
         Map<Object, Object> map = (Map<Object, Object>) sessionMap.get(prefix);
         if (map == null && create)
         {
             map = new ConcurrentHashMap<Object, Object>();
             sessionMap.put(prefix, map);
         }
         return map;
     }
 }