/// 统计数据模型

class Stats {
  final int total;
  final Map<String, int> byQuestionType;
  final Map<String, int> byImportType;
  final Map<String, int> byChapter;

  Stats({
    this.total = 0,
    this.byQuestionType = const {},
    this.byImportType = const {},
    this.byChapter = const {},
  });

  factory Stats.fromJson(Map<String, dynamic> json) {
    return Stats(
      total: json['total'] ?? 0,
      byQuestionType: Map<String, int>.from(json['by_question_type'] ?? {}),
      byImportType: Map<String, int>.from(json['by_import_type'] ?? {}),
      byChapter: Map<String, int>.from(json['by_chapter'] ?? {}),
    );
  }
}