ANTOOZA-BACKEND/Application/Features/Api/Member/Items/Unequip/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.Member.Items.Unequip;

/// <summary>지위 아이템 장착 해제. 이미 미장착이면 무해(idempotent).</summary>
internal sealed class Handler(IAppDbContext db) : ICommandHandler<Command, Result<Response>>
{
    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        var item = await db.MemberItem.FirstOrDefaultAsync(i => i.ID == request.MemberItemID, ct);

        if (item is null || item.MemberID != request.MemberID)
        {
            return Result.Failure<Response>(Error.NotFound("MemberItem.NotFound", "보유 아이템을 찾을 수 없습니다."));
        }

        if (item.EquipSlot is null)
        {
            return Result.Failure<Response>(Error.Problem("MemberItem.NotEquippable", "장착할 수 없는 아이템입니다."));
        }

        if (item.IsEquipped)
        {
            item.Unequip();
            await db.SaveChangesAsync(ct);
        }

        return Result.Success(new Response(item.ID, item.EquipSlot.Value, false));
    }
}