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

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

namespace Application.Features.Api.Crew.GetInvite;

internal sealed class Handler(
    IAppDbContext db
) : IQueryHandler<Query, Result<Response>>
{
    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var invitation = await db.CrewInvitation.AsNoTracking().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.RequesterMemberID)
        {
            return Result.Failure<Response>(Error.Forbidden("CrewInvitation.NotForYou", "본인에게 온 초대만 조회할 수 있습니다."));
        }

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

        if (crew is null)
        {
            return Result.Failure<Response>(Error.NotFound("Crew.NotFound", "크루를 찾을 수 없습니다."));
        }

        // 초대자 채널명 — Channel 우선, 없으면 Member.Name fallback
        var inviterChannelName = await db.Channel.AsNoTracking()
            .Where(c => c.MemberID == invitation.InvitedByMemberID)
            .Select(c => c.Name)
            .FirstOrDefaultAsync(ct);

        if (string.IsNullOrWhiteSpace(inviterChannelName))
        {
            inviterChannelName = await db.Member.AsNoTracking()
                .Where(m => m.ID == invitation.InvitedByMemberID)
                .Select(m => m.Name)
                .FirstOrDefaultAsync(ct) ?? "(알 수 없음)";
        }

        var isExpired = invitation.IsExpired();

        return Result.Success(new Response(
            invitation.ID,
            invitation.CrewID,
            crew.Name,
            inviterChannelName,
            invitation.Nickname,
            (byte)invitation.Status,
            invitation.InvitedAt,
            invitation.ExpiresAt,
            isExpired
        ));
    }
}