/*

  * $Id$

  *

  * 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;

     }

 }