import 'json_util.dart';

/// 预算信息（对应后端 BudgetResponse，仅当月有效）
class BudgetInfo {
  final int? id;
  final int? year;
  final int? month;
  final double amount; // 预算总额
  final double usedAmount; // 已用
  final double remainingAmount; // 剩余
  final double remainingDaily; // 日均可用

  const BudgetInfo({
    this.id,
    this.year,
    this.month,
    required this.amount,
    required this.usedAmount,
    required this.remainingAmount,
    required this.remainingDaily,
  });

  bool get hasBudget => amount > 0;

  bool get isOverBudget => amount > 0 && usedAmount > amount;

  /// 已用占比（0~1），未设预算时为 0
  double get usedRatio {
    if (amount <= 0 || !usedAmount.isFinite) return 0;
    return (usedAmount / amount).clamp(0.0, 1.0);
  }

  factory BudgetInfo.fromJson(Map<String, dynamic> json) {
    final amount = asDouble(json['amount']);
    final used = asDouble(json['usedAmount']);
    return BudgetInfo(
      id: json['id'] == null ? null : asInt(json['id']),
      year: json['year'] == null ? null : asInt(json['year']),
      month: json['month'] == null ? null : asInt(json['month']),
      amount: amount,
      usedAmount: used,
      remainingAmount:
          json['remainingAmount'] == null ? amount - used : asDouble(json['remainingAmount']),
      remainingDaily: asDouble(json['remainingDaily']),
    );
  }

  static const empty = BudgetInfo(
    amount: 0,
    usedAmount: 0,
    remainingAmount: 0,
    remainingDaily: 0,
  );
}