parse method

@override Element? parse(BlockParser parser)

Implementation

@override
md.Element? parse(md.BlockParser parser) {
  // Get the current line being parsed.
  final md.Line firstLine = parser.current;

  // --- Debugging Prints ---
  // Print the content of the current line the parser is looking at,
  // including showing potential hidden characters.
  print('WidgetBlockSyntax: Checking line for start pattern:');
  print('  Content (raw): "${firstLine.content}"');
  print('  Content (debug): "${firstLine.content.replaceAll(' ', '_').replaceAll('\n', '\\n')}"'); // Replace space with _, newline with \n for visibility
  // --- End Debugging Prints ---

  // Attempt to match the start pattern against the content of the current line.
  final RegExpMatch? startMatch = pattern.firstMatch(firstLine.content);

  // If no match for the start pattern, this block syntax doesn't apply.
  if (startMatch == null) {
    // --- Debugging Prints ---
    print('WidgetBlockSyntax: Start pattern did NOT match.');
    // --- End Debugging Prints ---
    return null;
  }

  // --- Debugging Prints ---
  print('WidgetBlockSyntax: Start pattern matched!');
  print('  Start match (group 0): "${startMatch.group(0)}"');
  print('  Label group (1): "${startMatch.group(1)}"');
  // --- End Debugging Prints ---


  // Extract the label (group 1).
  final String label = startMatch.group(1)!;

  // Consume the first line (the start fence).
  parser.advance();

  // Collect lines until the end fence is found.
  final List<String> contentLines = [];
  int linesConsumed = 1; // Start with 1 line consumed (the start fence)

  while (!parser.isDone) {
    final md.Line currentLine = parser.current;

    // --- Debugging Prints ---
    print('WidgetBlockSyntax: Checking line for end pattern:');
    print('  Content (raw): "${currentLine.content}"');
    print('  Content (debug): "${currentLine.content.replaceAll(' ', '_').replaceAll('\n', '\\n')}"'); // Replace space with _, newline with \n for visibility
    // --- End Debugging Prints ---

    // Check if the current line matches the end fence pattern.
    final RegExpMatch? endMatch = RegExp(_endPattern).firstMatch(currentLine.content);

    if (endMatch != null) {
      // Found the end fence.
      // Consume the end fence line.
      parser.advance();
      linesConsumed++;
      // --- Debugging Prints ---
      print('WidgetBlockSyntax: End pattern matched. Consumed end fence.');
      // --- End Debugging Prints ---
      break; // Exit the loop
    }

    // Add the current line's content to the collected lines.
    contentLines.add(currentLine.content);
    // Consume the current line.
    parser.advance();
    linesConsumed++;
    // --- Debugging Prints ---
    print('WidgetBlockSyntax: Added line to content: "${currentLine.content}"');
    // --- End Debugging Prints ---
  }

  // Join the collected lines to form the JSON string content.
  // Trim potential leading/trailing whitespace from the joined content.
  final String jsonString = contentLines.join('\n').trim();


  // Create a custom Markdown element.
  // The tag 'widgetBlock' is arbitrary but should be unique and used
  // to map to our custom builder (WidgetElementBuilder).
  // We store the extracted label and JSON string in the element's attributes.
  // Using the main Element constructor with tag and empty children list.
  // final element = md.Element('widgetBlock', []);
  // final element = md.Element('blockquote', []);
  // final element = md.Element.empty('widget');
  final element = md.Element('widget', []);
  // final element = md.Element.empty('widgetBlock');
  element.attributes.addAll({
    'label': label,
    'data': jsonString,
  });

  // --- Debugging Prints ---
  print('WidgetBlockSyntax: Element created with tag "${element.tag}", attributes "${element.attributes}".');
  print('WidgetBlockSyntax: Total lines consumed: $linesConsumed');
  // Removed print for element.type and element.parent as they are not available in this version.
  // --- End Debugging Prints ---

  return element; // Return the created element
}