/// In-site notification fetched from the notification-service backend.
class InSiteNotification {
  final String id;
  final String title;
  final String content;
  final String type; // SYSTEM | MAINTENANCE | FEATURE | ANNOUNCEMENT | BILLING | SECURITY
  final String priority; // LOW | NORMAL | HIGH | URGENT
  final String? imageUrl;
  final String? linkUrl;
  final bool requiresForceRead;
  final DateTime? publishedAt;
  final bool isRead;

  const InSiteNotification({
    required this.id,
    required this.title,
    required this.content,
    required this.type,
    required this.priority,
    this.imageUrl,
    this.linkUrl,
    required this.requiresForceRead,
    this.publishedAt,
    required this.isRead,
  });

  factory InSiteNotification.fromJson(Map<String, dynamic> json) {
    return InSiteNotification(
      id: json['id'] as String,
      title: json['title'] as String? ?? '',
      content: json['content'] as String? ?? '',
      type: json['type'] as String? ?? 'ANNOUNCEMENT',
      priority: json['priority'] as String? ?? 'NORMAL',
      imageUrl: json['imageUrl'] as String?,
      linkUrl: json['linkUrl'] as String?,
      requiresForceRead: json['requiresForceRead'] as bool? ?? false,
      publishedAt: json['publishedAt'] != null
          ? DateTime.tryParse(json['publishedAt'] as String)
          : null,
      isRead: json['isRead'] as bool? ?? false,
    );
  }

  InSiteNotification copyWith({bool? isRead}) => InSiteNotification(
        id: id,
        title: title,
        content: content,
        type: type,
        priority: priority,
        imageUrl: imageUrl,
        linkUrl: linkUrl,
        requiresForceRead: requiresForceRead,
        publishedAt: publishedAt,
        isRead: isRead ?? this.isRead,
      );

  String get typeLabel {
    const labels = {
      'SYSTEM': '系统通知',
      'MAINTENANCE': '维护通知',
      'FEATURE': '新功能',
      'ANNOUNCEMENT': '公告',
      'BILLING': '账单通知',
      'SECURITY': '安全通知',
    };
    return labels[type] ?? type;
  }

  String get typeEmoji {
    const emojis = {
      'SYSTEM': '⚙️',
      'MAINTENANCE': '🔧',
      'FEATURE': '✨',
      'ANNOUNCEMENT': '📢',
      'BILLING': '💳',
      'SECURITY': '🔒',
    };
    return emojis[type] ?? '📩';
  }

  String get relativeTime {
    final ref = publishedAt ?? DateTime.now();
    final diff = DateTime.now().difference(ref);
    if (diff.inMinutes < 1) return '刚刚';
    if (diff.inHours < 1) return '${diff.inMinutes}分钟前';
    if (diff.inDays < 1) return '${diff.inHours}小时前';
    if (diff.inDays < 30) return '${diff.inDays}天前';
    return '${ref.year}-${ref.month.toString().padLeft(2, '0')}-${ref.day.toString().padLeft(2, '0')}';
  }
}