ANTOOZA-BACKEND/Application/Features/Api/ChannelTitle/DeleteChannelTitle/Handler.cs

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

namespace Application.Features.Api.ChannelTitle.DeleteChannelTitle;

internal sealed class Handler(IAppDbContext db) : ICommandHandler<Command, Result>
{
    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        var title = await db.ChannelTitle.Include(t => t.Channel).FirstOrDefaultAsync(t => t.ID == request.TitleID, ct);
        if (title is null)
        {
            return Result.Failure(Error.NotFound("ChannelTitle.NotFound", "칭호를 찾을 수 없습니다."));
        }

        if (title.Channel is null || title.Channel.MemberID != request.MemberID)
        {
            return Result.Failure(Error.Forbidden("ChannelTitle.Forbidden", "본인 채널의 칭호만 삭제할 수 있습니다."));
        }

        // 관련 선택 기록의 참조는 SetNull FK로 자동 처리됨
        db.ChannelTitle.Remove(title);
        await db.SaveChangesAsync(ct);

        return Result.Success();
    }
}