dpot-backend/Application/Features/Api/Crew/GetActiveCrewForChannel/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Donations.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.Crew.GetActiveCrewForChannel;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response?>
{
    public async Task<Response?> Handle(Query request, CancellationToken ct)
    {
        var channel = await db.Channel.AsNoTracking()
            .FirstOrDefaultAsync(c => c.SID == request.ChannelSID, ct);

        if (channel is null) return null;

        // 채널에 연결된 크루 중 Active 세션이 있는지 확인
        var session = await db.CrewSession.AsNoTracking()
            .Where(s => s.Status == CrewSessionStatus.Active)
            .Join(db.Crew.Where(c => c.ChannelID == channel.ID), s => s.CrewID, c => c.ID, (s, c) => new { Session = s, Crew = c })
            .FirstOrDefaultAsync(ct);

        if (session is null) return null;

        var members = await db.CrewDonationSummary.AsNoTracking()
            .Where(s => s.CrewSessionID == session.Session.ID)
            .Join(db.CrewMember, s => s.CrewMemberID, m => m.ID, (s, m) => new { Summary = s, Member = m })
            .OrderBy(x => x.Summary.Rank)
            .Select(x => new CrewMemberInfo(
                x.Member.ID,
                x.Member.Nickname,
                x.Member.Member != null ? x.Member.Member.Thumb : null,
                x.Member.Channel != null ? x.Member.Channel.Name : null
            ))
            .ToListAsync(ct);

        return new Response(
            session.Session.ID,
            session.Session.Title,
            session.Crew.Name,
            members
        );
    }
}