String highlight()

in lib/src/highlighter.dart [190:261]
55 lines of code
17 McCabe index (conditional complexity)

  String highlight() {
    _writeFileStart(_lines.first.url);

    // Each index of this list represents a column after the sidebar that could
    // contain a line indicating an active highlight. If it's `null`, that
    // column is empty; if it contains a highlight, it should be drawn for that column.
    final highlightsByColumn =
        List<_Highlight?>.filled(_maxMultilineSpans, null);

    for (var i = 0; i < _lines.length; i++) {
      final line = _lines[i];
      if (i > 0) {
        final lastLine = _lines[i - 1];
        if (lastLine.url != line.url) {
          _writeSidebar(end: glyph.upEnd);
          _buffer.writeln();
          _writeFileStart(line.url);
        } else if (lastLine.number + 1 != line.number) {
          _writeSidebar(text: '...');
          _buffer.writeln();
        }
      }

      // If a highlight covers the entire first line other than initial
      // whitespace, don't bother pointing out exactly where it begins. Iterate
      // in reverse so that longer highlights (which are sorted after shorter
      // highlights) appear further out, leading to fewer crossed lines.
      for (var highlight in line.highlights.reversed) {
        if (isMultiline(highlight.span) &&
            highlight.span.start.line == line.number &&
            _isOnlyWhitespace(
                line.text.substring(0, highlight.span.start.column))) {
          replaceFirstNull(highlightsByColumn, highlight);
        }
      }

      _writeSidebar(line: line.number);
      _buffer.write(' ');
      _writeMultilineHighlights(line, highlightsByColumn);
      if (highlightsByColumn.isNotEmpty) _buffer.write(' ');

      final primaryIdx =
          line.highlights.indexWhere((highlight) => highlight.isPrimary);
      final primary = primaryIdx == -1 ? null : line.highlights[primaryIdx];

      if (primary != null) {
        _writeHighlightedText(
            line.text,
            primary.span.start.line == line.number
                ? primary.span.start.column
                : 0,
            primary.span.end.line == line.number
                ? primary.span.end.column
                : line.text.length,
            color: _primaryColor);
      } else {
        _writeText(line.text);
      }
      _buffer.writeln();

      // Always write the primary span's indicator first so that it's right next
      // to the highlighted text.
      if (primary != null) _writeIndicator(line, primary, highlightsByColumn);
      for (var highlight in line.highlights) {
        if (highlight.isPrimary) continue;
        _writeIndicator(line, highlight, highlightsByColumn);
      }
    }

    _writeSidebar(end: glyph.upEnd);
    return _buffer.toString();
  }