// 班级数据模型 — 手写不可变类（避免 build_runner 依赖）

import 'package:uuid/uuid.dart';

/// 班级 — 老师创建，学生通过班级码加入
///
/// 班级码安全规则：
/// - 6 位字母数字混合（62^6 约 568 亿种组合）
/// - 有效期控制（学期结束自动失效）
/// - 连续 5 次错误锁定 30 分钟
class SchoolClass {
  final String id;
  final String name;
  final String schoolName;
  final String teacherId;
  final String classCode;
  final int memberCount;
  final bool isActive;
  final DateTime? expiresAt;
  final DateTime createdAt;
  final DateTime updatedAt;

  const SchoolClass({
    required this.id,
    required this.name,
    required this.schoolName,
    required this.teacherId,
    required this.classCode,
    this.memberCount = 0,
    this.isActive = true,
    this.expiresAt,
    required this.createdAt,
    required this.updatedAt,
  });

  SchoolClass copyWith({
    String? id,
    String? name,
    String? schoolName,
    String? teacherId,
    String? classCode,
    int? memberCount,
    bool? isActive,
    DateTime? expiresAt,
    bool clearExpiresAt = false,
    DateTime? createdAt,
    DateTime? updatedAt,
  }) =>
      SchoolClass(
        id: id ?? this.id,
        name: name ?? this.name,
        schoolName: schoolName ?? this.schoolName,
        teacherId: teacherId ?? this.teacherId,
        classCode: classCode ?? this.classCode,
        memberCount: memberCount ?? this.memberCount,
        isActive: isActive ?? this.isActive,
        expiresAt: clearExpiresAt ? null : (expiresAt ?? this.expiresAt),
        createdAt: createdAt ?? this.createdAt,
        updatedAt: updatedAt ?? this.updatedAt,
      );

  Map<String, dynamic> toJson() => {
        'id': id,
        'name': name,
        'school_name': schoolName,
        'teacher_id': teacherId,
        'class_code': classCode,
        'member_count': memberCount,
        'is_active': isActive,
        'expires_at': expiresAt?.toIso8601String(),
        'created_at': createdAt.toIso8601String(),
        'updated_at': updatedAt.toIso8601String(),
      };

  factory SchoolClass.fromJson(Map<String, dynamic> json) => SchoolClass(
        id: json['id'] as String,
        name: json['name'] as String,
        schoolName: json['school_name'] as String,
        teacherId: json['teacher_id'] as String,
        classCode: json['class_code'] as String,
        memberCount: (json['member_count'] as int?) ?? 0,
        isActive: (json['is_active'] as bool?) ?? true,
        expiresAt: json['expires_at'] != null
            ? DateTime.parse(json['expires_at'] as String)
            : null,
        createdAt: DateTime.parse(json['created_at'] as String),
        updatedAt: DateTime.parse(json['updated_at'] as String),
      );

  /// 创建新班级的工厂方法 — 自动生成 id 和时间戳
  factory SchoolClass.create({
    required String name,
    required String schoolName,
    required String teacherId,
    required String classCode,
    DateTime? expiresAt,
  }) {
    final now = DateTime.now();
    return SchoolClass(
      id: const Uuid().v4(),
      name: name,
      schoolName: schoolName,
      teacherId: teacherId,
      classCode: classCode,
      memberCount: 0,
      isActive: true,
      expiresAt: expiresAt,
      createdAt: now,
      updatedAt: now,
    );
  }
}