import 'package:flutter/material.dart';
import 'package:html/dom.dart' as dom;
import 'package:html/parser.dart' as html_parser;

class AlignedHtmlContent extends StatelessWidget {
  final String html;
  final TextStyle bodyStyle;
  final double markerWidth;

  const AlignedHtmlContent({
    super.key,
    required this.html,
    required this.bodyStyle,
    this.markerWidth = 32,
  });

  @override
  Widget build(BuildContext context) {
    final document = html_parser.parse(html);
    final body = document.body;
    if (body == null) return const SizedBox.shrink();

    return SizedBox(
      width: double.infinity,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: _buildNodes(body.nodes),
      ),
    );
  }

  List<Widget> _buildNodes(List<dom.Node> nodes) {
    final widgets = <Widget>[];
    for (final node in nodes) {
      widgets.addAll(_buildNode(node));
    }
    return widgets;
  }

  List<Widget> _buildNode(dom.Node node) {
    if (node is dom.Text) {
      final text = _normalizeWhitespace(node.text);
      if (text.isEmpty) return [];
      return [Text(text, style: bodyStyle)];
    }
    if (node is! dom.Element) return [];

    switch (node.localName) {
      case 'p':
        final text = _normalizeWhitespace(node.text);
        if (text.isEmpty) return [];
        return [
          Padding(
            padding: const EdgeInsets.only(bottom: 8),
            child: Text(text, style: bodyStyle),
          ),
        ];
      case 'ol':
        return [_buildOrderedList(node, 0)];
      case 'ul':
        return [_buildUnorderedList(node, 0)];
      case 'br':
        return [const SizedBox(height: 8)];
      default:
        return _buildNodes(node.nodes);
    }
  }

  Widget _buildOrderedList(dom.Element ol, double indent) {
    final items = ol.children.where((element) => element.localName == 'li');
    final children = <Widget>[];
    var index = 0;

    for (final item in items) {
      index += 1;
      children.add(
        Padding(
          padding: EdgeInsets.only(left: indent, bottom: 8),
          child: _buildOrderedListItem(item, index, indent),
        ),
      );
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: children,
    );
  }

  Widget _buildOrderedListItem(dom.Element li, int number, double indent) {
    final leadingText = _liLeadingText(li);
    final nestedLists =
        li.children.where((element) => element.localName == 'ol' || element.localName == 'ul');

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            SizedBox(
              width: markerWidth,
              child: Text(
                '$number.',
                style: bodyStyle.copyWith(
                  fontFeatures: const [FontFeature.tabularFigures()],
                ),
              ),
            ),
            Expanded(
              child: Text(
                leadingText,
                style: bodyStyle,
              ),
            ),
          ],
        ),
        for (final nested in nestedLists)
          Padding(
            padding: const EdgeInsets.only(top: 8),
            child: nested.localName == 'ol'
                ? _buildOrderedList(nested, indent + markerWidth)
                : _buildUnorderedList(nested, indent + markerWidth),
          ),
      ],
    );
  }

  Widget _buildUnorderedList(dom.Element ul, double indent) {
    final items = ul.children.where((element) => element.localName == 'li');
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        for (final item in items)
          Padding(
            padding: EdgeInsets.only(left: indent, bottom: 8),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                SizedBox(
                  width: markerWidth,
                  child: Text(
                    '•',
                    style: bodyStyle.copyWith(
                      color: const Color(0xFFE26728),
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ),
                Expanded(
                  child: Text(
                    _normalizeWhitespace(item.text),
                    style: bodyStyle,
                  ),
                ),
              ],
            ),
          ),
      ],
    );
  }

  String _liLeadingText(dom.Element li) {
    final buffer = StringBuffer();
    for (final node in li.nodes) {
      if (node is dom.Text) {
        buffer.write(node.text);
      } else if (node is dom.Element &&
          node.localName != 'ol' &&
          node.localName != 'ul') {
        buffer.write(node.text);
      }
    }
    return _normalizeWhitespace(buffer.toString());
  }

  String _normalizeWhitespace(String value) {
    return value.replaceAll(RegExp(r'\s+'), ' ').trim();
  }
}