render method

Implementation

@override
String render() {
  final content = _content.isEmpty ? [''] : _content;

  // Calculate content width
  var contentWidth = 0;
  for (final line in content) {
    final len = Style.visibleLength(line);
    if (len > contentWidth) contentWidth = len;
  }

  // Account for title width
  var titleWidth = 0;
  if (_title != null) {
    titleWidth = Style.visibleLength(_title!) + 4; // spaces and padding
  }

  // Calculate inner width
  var innerWidth = contentWidth;
  if (titleWidth > innerWidth) innerWidth = titleWidth;

  // Apply width constraints
  if (_minWidth != null && innerWidth < _minWidth!) {
    innerWidth = _minWidth!;
  }
  if (_maxWidth != null && innerWidth > _maxWidth!) {
    innerWidth = _maxWidth!;
  }
  if (_width != null) {
    innerWidth = _width! - 2 - _paddingLeft - _paddingRight;
  }

  // Total inner width including padding
  final totalInnerWidth = innerWidth + _paddingLeft + _paddingRight;

  final buffer = StringBuffer();
  final b = _border;

  // Helper to style border characters
  String styleBorder(String text) {
    if (_borderStyle == null) return text;
    return _renderConfig.configureStyle(_borderStyle!).render(text);
  }

  // Helper to style title
  String styleTitle(String text) {
    if (_titleStyle == null) return text;
    return _renderConfig.configureStyle(_titleStyle!).render(text);
  }

  // Helper to style content
  String styleContent(String text, int lineIndex) {
    if (_contentStyleFunc != null) {
      final style = _contentStyleFunc!(text, lineIndex);
      if (style != null) {
        return _renderConfig.configureStyle(style).render(text);
      }
      return text;
    }
    if (_contentStyle != null) {
      return _renderConfig.configureStyle(_contentStyle!).render(text);
    }
    return text;
  }

  // Build top border
  if (_title != null) {
    final styledTitle = ' ${styleTitle(_title!)} ';
    final titleLen = Style.visibleLength(styledTitle);
    final remaining = totalInnerWidth - titleLen;

    String topLine;
    switch (_titleAlign) {
      case PanelAlignment.left:
        final rightFill = b.top * (remaining - 1);
        topLine = '${b.topLeft}${b.top}$styledTitle$rightFill${b.topRight}';
      case PanelAlignment.center:
        final leftFill = b.top * (remaining ~/ 2);
        final rightFill = b.top * (remaining - remaining ~/ 2);
        topLine = '${b.topLeft}$leftFill$styledTitle$rightFill${b.topRight}';
      case PanelAlignment.right:
        final leftFill = b.top * (remaining - 1);
        topLine = '${b.topLeft}$leftFill$styledTitle${b.top}${b.topRight}';
    }
    buffer.writeln(styleBorder(topLine));
  } else {
    buffer.writeln(
      styleBorder('${b.topLeft}${b.top * totalInnerWidth}${b.topRight}'),
    );
  }

  // Add top padding lines
  for (var i = 0; i < _paddingTop; i++) {
    buffer.writeln(
      '${styleBorder(b.left)}${' ' * totalInnerWidth}${styleBorder(b.right)}',
    );
  }

  // Content lines
  for (var i = 0; i < content.length; i++) {
    final line = content[i];
    final visible = Style.visibleLength(line);
    final fill = innerWidth - visible;

    String alignedContent;
    switch (_contentAlign) {
      case PanelAlignment.left:
        alignedContent = '$line${' ' * (fill > 0 ? fill : 0)}';
      case PanelAlignment.center:
        final leftPad = ' ' * (fill ~/ 2);
        final rightPad = ' ' * (fill - fill ~/ 2);
        alignedContent = '$leftPad$line$rightPad';
      case PanelAlignment.right:
        alignedContent = '${' ' * (fill > 0 ? fill : 0)}$line';
    }

    final styledContent = styleContent(alignedContent, i);
    final leftPad = ' ' * _paddingLeft;
    final rightPad = ' ' * _paddingRight;

    buffer.writeln(
      '${styleBorder(b.left)}$leftPad$styledContent$rightPad${styleBorder(b.right)}',
    );
  }

  // Add bottom padding lines
  for (var i = 0; i < _paddingBottom; i++) {
    buffer.writeln(
      '${styleBorder(b.left)}${' ' * totalInnerWidth}${styleBorder(b.right)}',
    );
  }

  // Bottom border
  buffer.write(
    styleBorder(
      '${b.bottomLeft}${b.bottom * totalInnerWidth}${b.bottomRight}',
    ),
  );

  return buffer.toString();
}