/* 
    * Licensed 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.esigate.aggregator;
  
  import java.io.IOException;
  import java.io.Writer;
  import java.util.regex.Pattern;
  
  import org.esigate.HttpErrorPage;
  import org.esigate.Renderer;
  import org.esigate.impl.DriverRequest;
  import org.esigate.parser.Parser;
  
  /**
   * Parses a page to find tags to be replaced by contents from other providers.
   * 
   * Sample syntax used for includes :
   * <ul>
   * <li>
   * &lt;!--$includeblock$provider$page$blockname$--&gt;&lt;!--$endincludeblock$ --&gt;</li>
   * <li>&lt;!--$includetemplate$provider$page$templatename$--&gt;&lt;!-- $endincludetemplate$--&gt;</li>
   * <li>&lt;!--$beginput$name$--&gt;&lt;!--$endput$--&gt;</li>
   * </ul>
   * 
   * Sample syntax used inside included contents for template and block definition:
   * <ul>
   * <li>&lt;!--$beginblock$name$--&gt;</li>
   * <li>&lt;!--$begintemplate$name$--&gt;</li>
   * <li>&lt;!--$beginparam$name$--&gt;</li>
   * </ul>
   * 
   * @author Stanislav Bernatskyi
   * @author Francois-Xavier Bonnet
   */
  public class AggregateRenderer implements Renderer, Appendable {
      /** Generic pattern for all the tags we want to look for. */
      private static final Pattern PATTERN = Pattern.compile("<!--\\$[^>]*\\$-->");
  
      private final Parser parser = new Parser(PATTERN, IncludeBlockElement.TYPE, IncludeTemplateElement.TYPE,
              PutElement.TYPE);
      private Writer out;
  
      /** {@inheritDoc} */
      @Override
      public void render(DriverRequest httpRequest, String content, Writer outWriter) throws IOException, HttpErrorPage {
          this.out = outWriter;
          if (content == null) {
              return;
          }
          parser.setHttpRequest(httpRequest);
          parser.parse(content, this);
      }
  
      @Override
      public Appendable append(CharSequence csq) throws IOException {
          out.append(csq);
          return this;
      }
  
      @Override
      public Appendable append(char c) throws IOException {
          out.append(c);
          return this;
      }
  
      @Override
      public Appendable append(CharSequence csq, int start, int end) throws IOException {
          out.append(csq, start, end);
          return this;
      }
  
  }