int _parseCode(dynamic value) {
  if (value is int) return value;
  if (value is String) return int.tryParse(value) ?? -1;
  if (value is num) return value.toInt();
  return -1;
}

/// 统一 API 响应包装
/// 后端格式：{ "code": 0, "data": {...}, "message": "ok" }
class ApiResponse<T> {
  final int code;
  final T? data;
  final String message;

  const ApiResponse({
    required this.code,
    this.data,
    required this.message,
  });

  bool get isSuccess => code == 0;

  factory ApiResponse.fromJson(
    Map<String, dynamic> json,
    T Function(Object? json)? fromJsonT,
  ) {
    return ApiResponse<T>(
      code: _parseCode(json['code']),
      data: json['data'] != null && fromJsonT != null
          ? fromJsonT(json['data'])
          : json['data'] as T?,
      message: json['message'] as String? ?? json['msg'] as String? ?? '',
    );
  }
}

/// API 异常
class ApiException implements Exception {
  final int code;
  final String message;

  const ApiException({required this.code, required this.message});

  @override
  String toString() => 'ApiException($code): $message';
}