package org.daisy.pipeline.css.sass.impl;
   
   import java.io.IOException;
   import java.io.StringReader;
   import java.util.Optional;
   
   import org.antlr.runtime.ANTLRReaderStream;
   import org.antlr.runtime.CommonTokenStream;
   import org.antlr.runtime.RecognitionException;
  
  import org.apache.commons.text.StringEscapeUtils;
  
  import org.w3c.dom.Element;
  
  class DoxygenComment extends Comment {
  
  	final Optional<String> varName;
  	final Optional<String> type;
  	final Optional<String> brief;
  	final String body;
  	final Optional<Element> typeDef;
  
  	DoxygenComment(String varName, String type, String brief, String body, Element typeDef, Comment comment)
  			throws IllegalArgumentException {
  
  		super(comment.text, comment.column);
  		if (type != null && typeDef != null)
  			throw new IllegalArgumentException("Can not have both a type specified in a @var command, and a <type> command");
  		this.varName = Optional.ofNullable(varName);
  		this.type = Optional.ofNullable(type);
  		this.brief = Optional.ofNullable(brief);
  		this.body = processMarkdown(body);
  		this.typeDef = Optional.ofNullable(typeDef);
  	}
  
  	/**
  	 * @throw IllegalArgumentException if the provided comment does not have the expected
  	 *                                 formatting.
  	 */
  	static DoxygenComment of(Comment comment) throws IllegalArgumentException {
  		try {
  			// pre-processing
  			if (!comment.text.startsWith("*"))
  				throw new IllegalArgumentException("Not a Doxygen comment: " + comment);
  			StringBuilder input = new StringBuilder();
  			input.append("\n  ");
  			for (int i = 0; i < comment.column; i++)
  				input.append(" ");
  			input.append(comment.text);
  			input.append("\n");
  			// parse
  			DoxygenParser parser = new DoxygenParser(
  				new CommonTokenStream(
  					new DoxygenLexer(
  						new ANTLRReaderStream(
  							new StringReader(input.toString()))))).init(comment);
  			return parser.doxygen_comment();
  		} catch (RecognitionException|IllegalArgumentException e) {
  			throw new IllegalArgumentException("Not a valid Doxygen comment: " + comment, e);
  		} catch (IOException e) {
  			throw new RuntimeException(e); // should not happen
  		}
  	}
  
  	/**
  	 * Rendering markdown is currently the responsibility to the client. However for convenience we
  	 * do a little bit of processing in the engine.
  	 */
  	private static String processMarkdown(String markdown) {
  		// replace HTML character entities
  		return StringEscapeUtils.unescapeHtml4(markdown);
  	}
  }