class FeedItem {
  final int? id;
  final String title;
  final String description;

  // the extracted article body — may be empty for older rows or sources
  // that havent been backfilled yet.
  final String content;

  final String link;
  final String? source;
  final DateTime? pubDate;

  FeedItem({
    this.id,
    required this.title,
    required this.description,
    this.content = "",
    required this.link,
    this.source,
    this.pubDate,
  });

  @override
  String toString() => 'FeedItem(title: $title, link: $link)';

  FeedItem.fromJson(Map<String, dynamic> json)
      : id = json['id'] is int ? json['id'] as int : int.tryParse('${json['id']}'),
        title = json['title'] ?? '',
        description = json['description'] ?? '',
        content = (json['content'] ?? '').toString(),
        link = json['link'] ?? '',
        source = json['source'],
        pubDate = json['pub_date'] != null ? DateTime.tryParse(json['pub_date']) : null;

  Map<String, dynamic> toJson() {
    return {
      if (id != null) 'id': id,
      'title': title,
      'description': description,
      if (content.isNotEmpty) 'content': content,
      'link': link,
      if (source != null) 'source': source,
      if (pubDate != null) 'pub_date': pubDate!.toIso8601String(),
    };
  }
}


// median pub date of a cluster — falls back to now if none have dates
DateTime medianPubDate(List<FeedItem> articles) {
  final dates = articles
      .where((a) => a.pubDate != null)
      .map((a) => a.pubDate!)
      .toList()
    ..sort();

  if (dates.isEmpty) return DateTime.now();
  return dates[dates.length ~/ 2];
}