class Invite {
  final String id;
  final String code;
  final String salesId;
  final String groupId;
  final String? link;
  final String? qrCodeUrl;
  final DateTime? createdAt;
  final DateTime? expiresAt;
  final int clickCount;
  final int scanCount;
  final int joinCount;
  final String status;

  Invite({
    required this.id,
    required this.code,
    required this.salesId,
    required this.groupId,
    this.link,
    this.qrCodeUrl,
    this.createdAt,
    this.expiresAt,
    this.clickCount = 0,
    this.scanCount = 0,
    this.joinCount = 0,
    this.status = 'active',
  });

  factory Invite.fromJson(Map<String, dynamic> json) {
    return Invite(
      id: (json['_id'] ?? json['id'] ?? '').toString(),
      code: json['code'] ?? '',
      salesId: (json['salesId'] ?? '').toString(),
      groupId: (json['groupId'] ?? '').toString(),
      link: json['link'],
      qrCodeUrl: json['qrCodeUrl'],
      createdAt: json['createdAt'] != null
          ? DateTime.parse(json['createdAt'].toString())
          : null,
      expiresAt: json['expiresAt'] != null
          ? DateTime.parse(json['expiresAt'].toString())
          : null,
      clickCount: json['clickCount'] ?? 0,
      scanCount: json['scanCount'] ?? 0,
      joinCount: json['joinCount'] ?? 0,
      status: json['status'] ?? 'active',
    );
  }

  Map<String, dynamic> toJson() {
    return {
      '_id': id,
      'code': code,
      'salesId': salesId,
      'groupId': groupId,
      'link': link,
      'qrCodeUrl': qrCodeUrl,
      'createdAt': createdAt?.toIso8601String(),
      'expiresAt': expiresAt?.toIso8601String(),
      'clickCount': clickCount,
      'scanCount': scanCount,
      'joinCount': joinCount,
      'status': status,
    };
  }

  bool get isExpired =>
      expiresAt != null && DateTime.now().isAfter(expiresAt!);
  bool get isActive => status == 'active' && !isExpired;
  bool get isValid => isActive;
}

/// 单个邀请的统计数据，由 invite.getStats 返回
class InviteStats {
  final String code;
  final String? link;
  final DateTime? createdAt;
  final DateTime? expiresAt;
  final InviteStatsDetail stats;
  final List<AccessLog> recentAccess;

  InviteStats({
    required this.code,
    this.link,
    this.createdAt,
    this.expiresAt,
    required this.stats,
    this.recentAccess = const [],
  });

  factory InviteStats.fromJson(Map<String, dynamic> json) {
    return InviteStats(
      code: json['code'] ?? '',
      link: json['link'],
      createdAt: json['createdAt'] != null
          ? DateTime.parse(json['createdAt'].toString())
          : null,
      expiresAt: json['expiresAt'] != null
          ? DateTime.parse(json['expiresAt'].toString())
          : null,
      stats: InviteStatsDetail.fromJson(json['stats'] ?? {}),
      recentAccess: (json['recentAccess'] as List?)
              ?.map((e) => AccessLog.fromJson(e))
              .toList() ??
          [],
    );
  }
}

class InviteStatsDetail {
  final int clicks;
  final int scans;
  final int joins;
  final String conversionRate;

  InviteStatsDetail({
    this.clicks = 0,
    this.scans = 0,
    this.joins = 0,
    this.conversionRate = '0',
  });

  factory InviteStatsDetail.fromJson(Map<String, dynamic> json) {
    return InviteStatsDetail(
      clicks: json['clicks'] ?? 0,
      scans: json['scans'] ?? 0,
      joins: json['joins'] ?? 0,
      conversionRate: json['conversionRate']?.toString() ?? '0',
    );
  }

  double get conversionRateDouble => double.tryParse(conversionRate) ?? 0.0;
}

/// 来自后端的访问日志条目
class AccessLog {
  final String? id;
  final String inviteCode;
  final String? visitorId;
  final String accessType;
  final DateTime? timestamp;
  final String? ipAddress;

  AccessLog({
    this.id,
    required this.inviteCode,
    this.visitorId,
    required this.accessType,
    this.timestamp,
    this.ipAddress,
  });

  factory AccessLog.fromJson(Map<String, dynamic> json) {
    return AccessLog(
      id: (json['_id'] ?? json['id'])?.toString(),
      inviteCode: json['inviteCode'] ?? '',
      visitorId: json['visitorId']?.toString(),
      accessType: json['accessType'] ?? '',
      timestamp: json['timestamp'] != null
          ? DateTime.parse(json['timestamp'].toString())
          : null,
      ipAddress: json['ipAddress'],
    );
  }
}