import '../utils/date_util.dart';
import 'json_util.dart';

/// 账单（对应后端 BillResponse）
///
/// 注意：amount 后端恒返回正数，收支方向看 [type]。
class Bill {
  final int id;
  final int categoryId;
  final String categoryName;
  final String categoryIcon;
  final double amount;
  final String description;
  final String billDate; // yyyy-MM-dd
  final String? imageUrl;
  final int type; // 1=支出 2=收入
  final String? createTime;
  final String? updateTime;

  const Bill({
    required this.id,
    required this.categoryId,
    required this.categoryName,
    required this.categoryIcon,
    required this.amount,
    required this.description,
    required this.billDate,
    this.imageUrl,
    required this.type,
    this.createTime,
    this.updateTime,
  });

  bool get isExpense => type == 1;

  double get absAmount => amount.abs();

  factory Bill.fromJson(Map<String, dynamic> json) => Bill(
        id: asInt(json['id']),
        categoryId: asInt(json['categoryId']),
        categoryName: asNonEmpty(json['categoryName'], '未分类'),
        categoryIcon: asNonEmpty(json['categoryIcon'], 'other'),
        amount: asDouble(json['amount']),
        description: asString(json['description']),
        billDate: parseBillDate(asString(json['billDate'])),
        imageUrl: json['imageUrl'] == null ? null : asString(json['imageUrl']),
        // 后端可能返回 null，缺省按支出处理
        type: asInt(json['type'], fallback: 1) == 2 ? 2 : 1,
        createTime: json['createTime'] == null ? null : asString(json['createTime']),
        updateTime: json['updateTime'] == null ? null : asString(json['updateTime']),
      );
}