/*
    * $Id: VelocityAutotagRuntime.java 1360343 2012-07-11 18:35:52Z nlebas $
    *
    * 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.tiles.request.velocity.autotag;
  
  import java.io.Writer;
  import java.util.Map;
  import javax.servlet.ServletContext;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import org.apache.tiles.autotag.core.runtime.ModelBody;
  import org.apache.tiles.autotag.core.runtime.AutotagRuntime;
  import org.apache.tiles.request.Request;
  import org.apache.tiles.request.servlet.ServletUtil;
  import org.apache.tiles.request.velocity.VelocityRequest;
  import org.apache.velocity.context.InternalContextAdapter;
  import org.apache.velocity.runtime.directive.Directive;
  import org.apache.velocity.runtime.parser.node.ASTBlock;
  import org.apache.velocity.runtime.parser.node.ASTMap;
  import org.apache.velocity.runtime.parser.node.Node;
  import org.apache.velocity.tools.view.ViewContext;
  
  /**
   * A Runtime for implementing Velocity Directives.
   */
  public class VelocityAutotagRuntime extends Directive implements AutotagRuntime<Request> {
      private InternalContextAdapter context;
      private Writer                 writer;
      private Node                   node;
      private Map<String, Object>    params;
  
      /** {@inheritDoc} */
      @Override
      public Request createRequest() {
          ViewContext viewContext = (ViewContext) context.getInternalUserContext();
          HttpServletRequest request = viewContext.getRequest();
          HttpServletResponse response = viewContext.getResponse();
          ServletContext servletContext = viewContext.getServletContext();
          return VelocityRequest.createVelocityRequest(ServletUtil.getApplicationContext(servletContext),
                                                       request,
                                                       response,
                                                       context,
                                                       writer);
      }
  
      /** {@inheritDoc} */
      @Override
      public ModelBody createModelBody() {
          ASTBlock block = (ASTBlock) node.jjtGetChild(1);
          return new VelocityModelBody(context, block, writer);
      }
  
      /** {@inheritDoc} */
      @Override
      @SuppressWarnings("unchecked")
      public <T> T getParameter(String name, Class<T> type, T defaultValue) {
          if (params == null) {
              ASTMap astMap = (ASTMap) node.jjtGetChild(0);
              params = (Map<String, Object>) astMap.value(context);
          }
          T result = (T) params.get(name);
          if (result == null) {
              result = defaultValue;
          }
          return result;
      }
  
      /** {@inheritDoc} */
      @Override
      public String getName() {
          return null;
      }
  
      /** {@inheritDoc} */
      @Override
      public int getType() {
          return 0;
      }
  
      /** {@inheritDoc} */
      @Override
      public boolean render(InternalContextAdapter context, Writer writer, Node node) {
         this.context = context;
         this.writer = writer;
         this.node = node;
         return false;
     }
 
 }