package org.esigate.tags;
   
   import java.io.IOException;
   
   import org.esigate.aggregator.AggregationSyntaxException;
   import org.esigate.parser.Element;
   import org.esigate.parser.ElementType;
   import org.esigate.parser.ParserContext;
   
  class BlockElement implements Element {
      public static final ElementType TYPE = new ElementType() {
  
          @Override
          public boolean isStartTag(String tag) {
              return tag.startsWith("<!--$beginblock$");
          }
  
          @Override
          public boolean isEndTag(String tag) {
              return tag.startsWith("<!--$endblock$");
          }
  
          @Override
          public Element newInstance() {
              return new BlockElement();
          }
  
          @Override
          public boolean isSelfClosing(String tag) {
              return false;
          }
  
      };
  
      private BlockRenderer blockRenderer;
      private boolean nameMatches;
  
      @Override
      public boolean onError(Exception e, ParserContext ctx) {
          return false;
      }
  
      @Override
      public void onTagEnd(String tag, ParserContext ctx) {
          // Stop writing
          if (nameMatches) {
              blockRenderer.setWrite(false);
          }
      }
  
      @Override
      public boolean onTagStart(String tag, ParserContext ctx) {
          String[] parameters = tag.split("\\$");
          if (parameters.length != 4) {
              throw new AggregationSyntaxException("Invalid syntax: " + tag);
          }
          String name = parameters[2];
          this.blockRenderer = ctx.findAncestor(BlockRenderer.class);
          // If name matches, start writing
          nameMatches = name.equals(blockRenderer.getName());
          if (nameMatches) {
              blockRenderer.setWrite(true);
          }
          return true;
      }
  
      @Override
      public void characters(CharSequence csq, int start, int end) throws IOException {
          blockRenderer.append(csq, start, end);
      }
  
  }