ANTOOZA-BACKEND/Application/Features/Api/Crew/DeclineInvite/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Hub;
using Application.Abstractions.Messaging;
using Application.Abstractions.Notification;
using SharedKernel;
using SharedKernel.Results;
using Domain.Entities.Donations.ValueObject;
using Domain.Entities.Notifications.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.Crew.DeclineInvite;

internal sealed class Handler(
    IAppDbContext db,
    INotificationService notificationService,
    ICrewHubBroadcaster crewBroadcaster
) : ICommandHandler<Command, Result<Response>>
{
    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        var invitation = await db.CrewInvitation.FirstOrDefaultAsync(i => i.ID == request.InvitationID, ct);

        if (invitation is null)
        {
            return Result.Failure<Response>(Error.NotFound("CrewInvitation.NotFound", "초대를 찾을 수 없습니다."));
        }

        if (invitation.TargetMemberID != request.MemberID)
        {
            return Result.Failure<Response>(Error.Forbidden("CrewInvitation.NotForYou", "본인에게 온 초대만 거절할 수 있습니다."));
        }

        if (invitation.Status != CrewInviteStatus.Pending)
        {
            return Result.Failure<Response>(Error.Conflict("CrewInvitation.NotPending", "대기 중인 초대만 거절할 수 있습니다."));
        }

        if (invitation.IsExpired())
        {
            invitation.MarkExpired();
            await db.SaveChangesAsync(ct);
            return Result.Failure<Response>(Error.Problem("CrewInvitation.Expired", "초대가 만료되었습니다."));
        }

        invitation.Decline();
        await db.SaveChangesAsync(ct);

        var crew = await db.Crew.AsNoTracking().FirstOrDefaultAsync(c => c.ID == invitation.CrewID, ct);

        // 운영자(초대 발송자)에게 알림 — AcceptInvite 와 일관되게 INotificationService 로 통일 (SignalR push 포함)
        await notificationService.SendAsync(
            memberID: invitation.InvitedByMemberID,
            type: NotificationType.CrewInvitation,
            title: $"크루 초대 거절",
            message: $"'{invitation.Nickname}' 님이 '{crew?.Name ?? "크루"}' 초대를 거절했습니다.",
            actionUrl: $"/studio/donation/crew/{invitation.CrewID}",
            relatedType: "CrewInvitation",
            relatedID: invitation.ID,
            imageUrl: null,
            ct: ct
        );

        // 운영자 그룹(crew:{crewID})에 초대 응답 broadcast → 멤버 리스트 자동 새로고침
        await crewBroadcaster.BroadcastMemberChangeAsync(
            crewID: invitation.CrewID,
            kind: "invitationStatusChanged",
            data: new
            {
                invitationID = invitation.ID,
                status = "Declined",
                crewID = invitation.CrewID
            },
            ct: ct
        );

        return Result.Success(new Response(invitation.ID));
    }
}