nj/app/lib/data/models/journal_entry.dart

// 日记条目数据模型 — 手写不可变类（避免 build_runner 依赖）

import 'package:uuid/uuid.dart';

/// 心情枚举 — 对应日记心情选择器
enum Mood {
  happy('happy'),
  calm('calm'),
  sad('sad'),
  angry('angry'),
  thinking('thinking');

  const Mood(this.value);
  final String value;
}

/// 天气枚举 — 对应日记天气标签
enum Weather {
  sunny('sunny'),
  cloudy('cloudy'),
  rainy('rainy'),
  snowy('snowy'),
  windy('windy');

  const Weather(this.value);
  final String value;
}

/// 日记条目 — 核心数据模型
///
/// 每篇日记包含标题、日期、心情、天气、标签等元信息。
/// 日记的具体内容（文字/图片/手写/贴纸）通过 [JournalElement] 管理。
class JournalEntry {
  final String id;
  final String authorId;
  final String? classId;
  final String title;
  final DateTime date;
  final Mood mood;
  final Weather weather;
  final List<String> tags;
  final bool isPrivate;
  final bool sharedToClass;
  final String? assignedTopicId;

  /// 内容摘要 — 自动从文本元素提取，用于列表预览
  final String? contentExcerpt;

  final int version;
  final DateTime createdAt;
  final DateTime updatedAt;

  const JournalEntry({
    required this.id,
    required this.authorId,
    this.classId,
    required this.title,
    required this.date,
    this.mood = Mood.calm,
    this.weather = Weather.sunny,
    this.tags = const [],
    this.isPrivate = true,
    this.sharedToClass = false,
    this.assignedTopicId,
    this.contentExcerpt,
    this.version = 1,
    required this.createdAt,
    required this.updatedAt,
  });

  JournalEntry copyWith({
    String? id,
    String? authorId,
    String? classId,
    bool clearClassId = false,
    String? title,
    DateTime? date,
    Mood? mood,
    Weather? weather,
    List<String>? tags,
    bool? isPrivate,
    bool? sharedToClass,
    String? assignedTopicId,
    bool clearAssignedTopicId = false,
    String? contentExcerpt,
    bool clearContentExcerpt = false,
    int? version,
    DateTime? createdAt,
    DateTime? updatedAt,
  }) =>
      JournalEntry(
        id: id ?? this.id,
        authorId: authorId ?? this.authorId,
        classId: clearClassId ? null : (classId ?? this.classId),
        title: title ?? this.title,
        date: date ?? this.date,
        mood: mood ?? this.mood,
        weather: weather ?? this.weather,
        tags: tags ?? this.tags,
        isPrivate: isPrivate ?? this.isPrivate,
        sharedToClass: sharedToClass ?? this.sharedToClass,
        assignedTopicId:
            clearAssignedTopicId ? null : (assignedTopicId ?? this.assignedTopicId),
        contentExcerpt: clearContentExcerpt
            ? null
            : (contentExcerpt ?? this.contentExcerpt),
        version: version ?? this.version,
        createdAt: createdAt ?? this.createdAt,
        updatedAt: updatedAt ?? this.updatedAt,
      );

  Map<String, dynamic> toJson() => {
        'id': id,
        'author_id': authorId,
        'class_id': classId,
        'title': title,
        'date': date.toIso8601String(),
        'mood': mood.value,
        'weather': weather.value,
        'tags': tags,
        'is_private': isPrivate,
        'shared_to_class': sharedToClass,
        'assigned_topic_id': assignedTopicId,
        'content_excerpt': contentExcerpt,
        'version': version,
        'created_at': createdAt.toIso8601String(),
        'updated_at': updatedAt.toIso8601String(),
      };

  factory JournalEntry.fromJson(Map<String, dynamic> json) => JournalEntry(
        id: json['id'] as String,
        authorId: json['author_id'] as String,
        classId: json['class_id'] as String?,
        title: json['title'] as String,
        date: DateTime.parse(json['date'] as String),
        mood: Mood.values.firstWhere(
          (m) => m.value == json['mood'],
          orElse: () => Mood.calm,
        ),
        weather: Weather.values.firstWhere(
          (w) => w.value == json['weather'],
          orElse: () => Weather.sunny,
        ),
        tags: List<String>.from(json['tags'] as List? ?? []),
        isPrivate: (json['is_private'] as bool?) ?? true,
        sharedToClass: (json['shared_to_class'] as bool?) ?? false,
        assignedTopicId: json['assigned_topic_id'] as String?,
        contentExcerpt: json['content_excerpt'] as String?,
        version: (json['version'] as int?) ?? 1,
        createdAt: DateTime.parse(json['created_at'] as String),
        updatedAt: DateTime.parse(json['updated_at'] as String),
      );

  /// 创建新日记的工厂方法 — 自动生成 id 和时间戳
  factory JournalEntry.create({
    required String authorId,
    required String title,
    required DateTime date,
    String? classId,
    Mood mood = Mood.calm,
    Weather weather = Weather.sunny,
    List<String> tags = const [],
    bool isPrivate = true,
    String? assignedTopicId,
  }) {
    final now = DateTime.now();
    return JournalEntry(
      id: const Uuid().v4(),
      authorId: authorId,
      classId: classId,
      title: title,
      date: date,
      mood: mood,
      weather: weather,
      tags: tags,
      isPrivate: isPrivate,
      sharedToClass: false,
      assignedTopicId: assignedTopicId,
      version: 1,
      createdAt: now,
      updatedAt: now,
    );
  }
}