ANTOOZA-BACKEND/Application/Features/Admin/Store/Order/RequestRefund/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;
using OrderRefundEntity = Domain.Entities.Store.OrderRefund;

namespace Application.Features.Admin.Store.Order.RequestRefund;

public sealed class Handler(IAppDbContext db) : ICommandHandler<Command, Result<int>>
{
    public async Task<Result<int>> Handle(Command request, CancellationToken ct)
    {
        var order = await db.Order.FirstOrDefaultAsync(o => o.ID == request.OrderID, ct);

        if (order is null)
        {
            return Result.Failure<int>(Error.NotFound("Order.NotFound", "주문을 찾을 수 없습니다."));
        }

        if (request.Amount <= 0 || request.Amount > order.TotalAmount)
        {
            return Result.Failure<int>(Error.Problem("Refund.InvalidAmount", $"환불 금액은 1 ~ {order.TotalAmount:N0}원 사이여야 합니다."));
        }

        var refund = OrderRefundEntity.Create(request.OrderID, request.Type, request.ReasonType, request.Amount, request.Reason);
        db.OrderRefund.Add(refund);

        await db.SaveChangesAsync(ct);

        return Result.Success(refund.ID);
    }
}