import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../core/api/api_client.dart';
import '../core/auth/auth_state.dart';

class LicenseInfo {
  final String type;       // trial / monthly / annual / lifetime
  final bool isActive;
  final DateTime? expiresAt;
  final DateTime? activatedAt;

  const LicenseInfo({
    required this.type,
    required this.isActive,
    this.expiresAt,
    this.activatedAt,
  });

  factory LicenseInfo.fromJson(Map<String, dynamic> json) {
    return LicenseInfo(
      type: json['type'] as String? ?? 'trial',
      isActive: json['is_active'] as bool? ?? false,
      expiresAt: json['expires_at'] != null
          ? DateTime.tryParse(json['expires_at'] as String)
          : null,
      activatedAt: json['activated_at'] != null
          ? DateTime.tryParse(json['activated_at'] as String)
          : null,
    );
  }

  String get typeLabel {
    switch (type) {
      case 'monthly': return '月度授权';
      case 'annual':  return '年度授权';
      case 'lifetime': return '永久授权';
      default:        return '试用版';
    }
  }

  /// 是否已过期
  bool get isExpired =>
      expiresAt != null && DateTime.now().isAfter(expiresAt!);

  /// 距到期剩余天数（null = 永久）
  int? get daysRemaining {
    if (expiresAt == null) return null;
    final diff = expiresAt!.difference(DateTime.now()).inDays;
    return diff < 0 ? 0 : diff;
  }
}

final licenseProvider =
    AsyncNotifierProvider<LicenseNotifier, LicenseInfo?>(LicenseNotifier.new);

class LicenseNotifier extends AsyncNotifier<LicenseInfo?> {
  @override
  Future<LicenseInfo?> build() async {
    ref.watch(authStateProvider.select((s) => s.user?.shopId));
    return _fetch();
  }

  Future<LicenseInfo?> _fetch() async {
    try {
      final client = ref.read(apiClientProvider);
      final resp = await client.get('/license/info');
      final data = resp.data['data'];
      if (data == null) return null;
      return LicenseInfo.fromJson(data as Map<String, dynamic>);
    } catch (_) {
      return null;
    }
  }

  Future<void> reload() async {
    state = const AsyncValue.loading();
    state = AsyncValue.data(await _fetch());
  }
}