/*
    * $Id$
    *
    * 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.mustache;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import com.github.mustachejava.MustacheFactory;
  import com.github.mustachejava.DefaultMustacheFactory;
  import com.github.mustachejava.MustacheException;
  import org.apache.tiles.request.Request;
  import org.apache.tiles.request.render.CannotRenderException;
  import org.apache.tiles.request.render.Renderer;
  
  /**
   * The Mustache-specific renderer.
   *
   * Can be configured to render paths only according to the acceptPattern.
   *
   * @version $Rev: 1215006 $ $Date: 2011-12-16 01:30:41 +0100 (Fri, 16 Dec 2011) $
   */
  public class MustacheRenderer implements Renderer {
  
      // hack. exposes the tiles Request for MustacheFactory implementations.
      private static final ThreadLocal<Request> REQUEST_HOLDER = new ThreadLocal<Request>();
  
      private final MustacheFactory factory;
      private Pattern acceptPattern;
  
      /** Uses the {@link DefaultMustacheFactory} */
      public MustacheRenderer(){
          this.factory = new DefaultMustacheFactory();
      }
  
      public MustacheRenderer(MustacheFactory factory) {
          this.factory = factory;
      }
  
      @Override
      public void render(String path, Request request) throws IOException {
          if (path == null) {
              throw new CannotRenderException("Cannot dispatch a null path");
          }
  
          try {
              REQUEST_HOLDER.set(request);
              factory
                      .compile(path)
                      .execute(request.getWriter(), buildScope(request));
              REQUEST_HOLDER.remove();
  
          } catch(MustacheException ex) {
              throw new IOException("failed to MustacheRenderer.render(" + path + ",request)", ex);
          }
      }
  
      public static Request getThreadLocalRequest() {
          return REQUEST_HOLDER.get();
      }
  
      protected Map<String,Object> buildScope(Request request) {
          Map<String,Object> scope = new HashMap<String,Object>();
          List<String> availableScopes = request.getAvailableScopes();
          for (int i = availableScopes.size() -1; i >= 0; --i) {
              scope.putAll(request.getContext(availableScopes.get(i)));
          }
          return scope;
      }
  
      @Override
      public boolean isRenderable(String path, Request request) {
          if (path == null) {
              return false;
          }
          if (acceptPattern != null) {
              final Matcher matcher = acceptPattern.matcher(path);
             return matcher.matches();
         }
         return true;
     }
 
     public final void setAcceptPattern(Pattern acceptPattern) {
         this.acceptPattern = acceptPattern;
     }
 }