import 'package:flutter/material.dart';

/// 要素模型
class DocumentElement {
  final String id;
  final ElementType type;
  final String label;
  final String value;
  final Offset? position; // 在文档中的位置
  final String? documentId;
  final Map<String, dynamic>? metadata;

  DocumentElement({
    required this.id,
    required this.type,
    required this.label,
    required this.value,
    this.position,
    this.documentId,
    this.metadata,
  });

  /// 从JSON创建
  factory DocumentElement.fromJson(Map<String, dynamic> json) {
    return DocumentElement(
      id: json['id'] as String,
      type: ElementType.values.firstWhere(
        (e) => e.toString().split('.').last == json['type'],
        orElse: () => ElementType.other,
      ),
      label: json['label'] as String,
      value: json['value'] as String,
      position: json['position'] != null
          ? Offset(
              (json['position'] as Map)['x'] as double,
              (json['position'] as Map)['y'] as double,
            )
          : null,
      documentId: json['documentId'] as String?,
      metadata: json['metadata'] as Map<String, dynamic>?,
    );
  }

  /// 转换为JSON
  Map<String, dynamic> toJson() {
    return {
      'id': id,
      'type': type.toString().split('.').last,
      'label': label,
      'value': value,
      'position':
          position != null ? {'x': position!.dx, 'y': position!.dy} : null,
      'documentId': documentId,
      'metadata': metadata,
    };
  }

  /// 复制并更新
  DocumentElement copyWith({
    String? id,
    ElementType? type,
    String? label,
    String? value,
    Offset? position,
    String? documentId,
    Map<String, dynamic>? metadata,
  }) {
    return DocumentElement(
      id: id ?? this.id,
      type: type ?? this.type,
      label: label ?? this.label,
      value: value ?? this.value,
      position: position ?? this.position,
      documentId: documentId ?? this.documentId,
      metadata: metadata ?? this.metadata,
    );
  }

  /// 显示文本
  String get displayText => '$label: $value';
}

/// 要素类型
enum ElementType {
  amount, // 金额
  company, // 公司
  person, // 人名
  location, // 地名
  date, // 日期
  other, // 其他
}

extension ElementTypeExtension on ElementType {
  String get label {
    switch (this) {
      case ElementType.amount:
        return '金额';
      case ElementType.company:
        return '公司';
      case ElementType.person:
        return '人名';
      case ElementType.location:
        return '地名';
      case ElementType.date:
        return '日期';
      case ElementType.other:
        return '其他';
    }
  }
}