ANTOOZA-BACKEND/Application/Features/Admin/Channel/YouTubePubSub/ForceLive/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Hub;
using Application.Abstractions.Messaging;
using Application.Abstractions.YouTube;
using Domain.Entities.Members;
using Domain.Entities.Members.ValueObject;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Admin.Channel.YouTubePubSub.ForceLive;

internal sealed class Handler(
    IAppDbContext db,
    IYouTubeLiveStateStore liveStateStore,
    IChannelStatusBroadcaster broadcaster
) : ICommandHandler<Command, Result>
{
    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.YouTubeChannelID) || string.IsNullOrWhiteSpace(request.VideoID))
        {
            return Result.Failure(Error.Problem("ForceLive.Invalid", "YouTube Channel ID 와 Video ID 가 필요합니다."));
        }

        var channel = await db.Channel.AsNoTracking()
            .FirstOrDefaultAsync(c => c.YouTubeChannelID == request.YouTubeChannelID && c.IsActive, ct);

        if (channel is null)
        {
            return Result.Failure(Error.NotFound("ForceLive.ChannelNotFound", "내부 Channel 을 찾을 수 없습니다."));
        }

        var title = string.IsNullOrWhiteSpace(request.Title) ? "(수동 등록 라이브)" : request.Title!;
        var now = DateTime.UtcNow;

        // YouTube API 호출 없이 LiveStreamInfo 수동 생성 — quota 0
        var liveInfo = new YouTubeLiveStreamInfo(
            VideoId: request.VideoID,
            Title: title,
            ChannelId: request.YouTubeChannelID,
            LiveBroadcastContent: "live",
            ActiveLiveChatId: null,
            ScheduledStartTime: null,
            ActualStartTime: now,
            ViewerCount: 0,
            ViewerCountUpdatedAt: now
        );

        // Redis 라이브 상태 저장
        await liveStateStore.SetLiveAsync(request.YouTubeChannelID, liveInfo);

        // DB BroadcastSession 생성 (없으면)
        var existing = await db.BroadcastSession
            .FirstOrDefaultAsync(b => b.Platform == BroadcastPlatform.YouTube && b.VideoID == request.VideoID, ct);

        if (existing is null)
        {
            var session = BroadcastSession.Create(channel.ID, BroadcastPlatform.YouTube, request.VideoID);
            session.UpdateStats(title, now, null, 0, 0);
            db.BroadcastSession.Add(session);
            await db.SaveChangesAsync(ct);
        }

        // SignalR 브로드캐스트 → ChannelSidebar / WatchView 실시간 반영
        await broadcaster.BroadcastAsync(channel.SID, isLive: true, viewerCount: 0, videoId: request.VideoID, ct);

        return Result.Success();
    }
}