ANTOOZA-BACKEND/Domain/Entities/Store/OrderRefundItem.cs

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Domain.Entities.Store.ValueObject;

namespace Domain.Entities.Store;

/// <summary>
/// 환불 단위 — 쿠폰 1개 = 1행. OrderRefund 1건에 N개의 OrderRefundItem (일괄 환불 지원).
///
/// 설계 이유: OrderRefund 자체는 Amount 합계만 가지고 있어 어떤 쿠폰/OrderItem 이
/// 환불되는지 추적 불가. 이 테이블이 정확한 환불 대상 + 후처리(회수/만료) 정책을 보관.
///
/// ProcessRefund 시 이 행들을 순회해:
///   - 다날 부분 취소 (OrderRefund.Amount 단위로 1회)
///   - 각 CouponCode 에 PostRefundAction 적용 (Restore / Expire)
///   - MemberInventory 의 해당 행 제거
/// </summary>
public class OrderRefundItem
{
    [ForeignKey(nameof(OrderRefundID))]
    public virtual OrderRefund? OrderRefund { get; private set; }

    [ForeignKey(nameof(OrderItemID))]
    public virtual OrderItem? OrderItem { get; private set; }

    [ForeignKey(nameof(CouponCodeID))]
    public virtual CouponCode? CouponCode { get; private set; }

    [Key]
    public int ID { get; private set; }

    public int OrderRefundID { get; private set; }

    public int OrderItemID { get; private set; }

    public int CouponCodeID { get; private set; }

    /// <summary>환불 단가 (스냅샷). OrderItem.UnitPrice 와 동일하지만 OrderItem 가격 변동 대비 보관.</summary>
    public int UnitAmount { get; private set; }

    public CouponPostRefundAction PostRefundAction { get; private set; }

    public DateTime CreatedAt { get; private set; } = DateTime.UtcNow;

    private OrderRefundItem() { }

    public static OrderRefundItem Create(int orderRefundID, int orderItemID, int couponCodeID, int unitAmount, CouponPostRefundAction action)
    {
        if (orderRefundID <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(orderRefundID));
        }

        if (orderItemID <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(orderItemID));
        }

        if (couponCodeID <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(couponCodeID));
        }

        if (unitAmount <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(unitAmount), "UnitAmount must be positive.");
        }

        return new OrderRefundItem
        {
            OrderRefundID = orderRefundID,
            OrderItemID = orderItemID,
            CouponCodeID = couponCodeID,
            UnitAmount = unitAmount,
            PostRefundAction = action
        };
    }
}