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

// 日记元素数据模型 — 手写不可变类（避免 build_runner 依赖）

import 'dart:collection';
import 'dart:ui';

import 'package:uuid/uuid.dart';

/// 元素类型 — 日记页面上的各种内容载体
enum ElementType {
  text('text'),
  image('image'),
  sticker('sticker'),
  handwritingRef('handwriting_ref'),
  tape('tape');

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

/// 日记元素 — 日记页面中的单个内容单元
///
/// 每个元素有独立的位置、尺寸、旋转和层级。
/// [content] 字段根据 [elementType] 存储不同的结构化数据：
/// - text: {'text': '...', 'fontSize': 16.0, 'fontColor': '#2D2420'}
/// - image: {'filePath': '...', 'thumbnailPath': '...'}
/// - sticker: {'stickerPackId': '...', 'stickerId': '...'}
/// - handwriting_ref: {'strokesFileId': '...', 'strokeCount': 42}
/// - tape: {'tapeStyle': 'washi_dots', 'tapeColor': '#F2CC8F'}
class JournalElement {
  final String id;
  final String journalId;
  final ElementType elementType;
  final double positionX;
  final double positionY;
  final double width;
  final double height;
  final double rotation;
  final int zIndex;
  final Map<String, dynamic> content;
  final int version;
  final DateTime createdAt;
  final DateTime updatedAt;

  const JournalElement({
    required this.id,
    required this.journalId,
    required this.elementType,
    this.positionX = 0,
    this.positionY = 0,
    this.width = 100,
    this.height = 100,
    this.rotation = 0,
    this.zIndex = 0,
    this.content = const {},
    this.version = 1,
    required this.createdAt,
    required this.updatedAt,
  });

  JournalElement copyWith({
    String? id,
    String? journalId,
    ElementType? elementType,
    double? positionX,
    double? positionY,
    double? width,
    double? height,
    double? rotation,
    int? zIndex,
    Map<String, dynamic>? content,
    int? version,
    DateTime? createdAt,
    DateTime? updatedAt,
  }) =>
      JournalElement(
        id: id ?? this.id,
        journalId: journalId ?? this.journalId,
        elementType: elementType ?? this.elementType,
        positionX: positionX ?? this.positionX,
        positionY: positionY ?? this.positionY,
        width: width ?? this.width,
        height: height ?? this.height,
        rotation: rotation ?? this.rotation,
        zIndex: zIndex ?? this.zIndex,
        content: content ?? this.content,
        version: version ?? this.version,
        createdAt: createdAt ?? this.createdAt,
        updatedAt: updatedAt ?? this.updatedAt,
      );

  Map<String, dynamic> toJson() => {
        'id': id,
        'journal_id': journalId,
        'element_type': elementType.value,
        'position_x': positionX,
        'position_y': positionY,
        'width': width,
        'height': height,
        'rotation': rotation,
        'z_index': zIndex,
        'content': content,
        'version': version,
        'created_at': createdAt.toIso8601String(),
        'updated_at': updatedAt.toIso8601String(),
      };

  factory JournalElement.fromJson(Map<String, dynamic> json) => JournalElement(
        id: json['id'] as String,
        journalId: json['journal_id'] as String,
        elementType: ElementType.values.firstWhere(
          (e) => e.value == json['element_type'],
          orElse: () => ElementType.text,
        ),
        positionX: (json['position_x'] as num?)?.toDouble() ?? 0,
        positionY: (json['position_y'] as num?)?.toDouble() ?? 0,
        width: (json['width'] as num?)?.toDouble() ?? 100,
        height: (json['height'] as num?)?.toDouble() ?? 100,
        rotation: (json['rotation'] as num?)?.toDouble() ?? 0,
        zIndex: (json['z_index'] as int?) ?? 0,
        content: UnmodifiableMapView(
          Map<String, dynamic>.from(json['content'] as Map? ?? {}),
        ),
        version: (json['version'] as int?) ?? 1,
        createdAt: DateTime.parse(json['created_at'] as String),
        updatedAt: DateTime.parse(json['updated_at'] as String),
      );

  /// 创建新元素的工厂方法 — 自动生成 id 和时间戳
  factory JournalElement.create({
    required String journalId,
    required ElementType elementType,
    double positionX = 0,
    double positionY = 0,
    double width = 100,
    double height = 100,
    double rotation = 0,
    int zIndex = 0,
    Map<String, dynamic> content = const {},
  }) {
    final now = DateTime.now();
    return JournalElement(
      id: const Uuid().v4(),
      journalId: journalId,
      elementType: elementType,
      positionX: positionX,
      positionY: positionY,
      width: width,
      height: height,
      rotation: rotation,
      zIndex: zIndex,
      content: content,
      version: 1,
      createdAt: now,
      updatedAt: now,
    );
  }

  /// 文字元素便利工厂
  factory JournalElement.createText({
    required String journalId,
    required String text,
    required Offset position,
    double fontSize = 18.0,
    String fontColor = '#2D2420',
  }) {
    return JournalElement.create(
      journalId: journalId,
      elementType: ElementType.text,
      positionX: position.dx,
      positionY: position.dy,
      content: {
        'text': text,
        'fontSize': fontSize,
        'fontColor': fontColor,
      },
    );
  }

  /// 图片元素便利工厂
  factory JournalElement.createImage({
    required String journalId,
    required String filePath,
    required Offset position,
    String? thumbnailPath,
  }) {
    return JournalElement.create(
      journalId: journalId,
      elementType: ElementType.image,
      positionX: position.dx,
      positionY: position.dy,
      content: {
        'filePath': filePath,
        if (thumbnailPath != null) 'thumbnailPath': thumbnailPath,
      },
    );
  }

  /// 贴纸元素便利工厂
  factory JournalElement.createSticker({
    required String journalId,
    required String emoji,
    required Offset position,
    String? stickerPackId,
    String? stickerId,
  }) {
    return JournalElement.create(
      journalId: journalId,
      elementType: ElementType.sticker,
      positionX: position.dx,
      positionY: position.dy,
      content: {
        'emoji': emoji,
        if (stickerPackId != null) 'stickerPackId': stickerPackId,
        if (stickerId != null) 'stickerId': stickerId,
      },
    );
  }
}