ANTOOZA-BACKEND/Application/Features/Api/Studio/DisconnectYouTube/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Application.Abstractions.YouTube;
using SharedKernel.Results;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;

namespace Application.Features.Api.Studio.DisconnectYouTube;

internal sealed class Handler(
    IAppDbContext db,
    IYouTubeChannelCache channelCache,
    IGoogleOAuthService oauthService,
    IYouTubePubSubService pubSubService,
    ILogger<Handler> logger
) : ICommandHandler<Command, Result>
{
    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        var channel = await db.Channel.FirstOrDefaultAsync(c => c.MemberID == request.MemberID && c.IsActive, ct);

        if (channel is null)
        {
            return Result.Failure(Error.NotFound("YouTube.ChannelNotConnected", "연동된 채널이 없습니다."));
        }

        // OAuth 토큰 조회 → revoke → 삭제
        var oauthToken = await db.MemberOAuthToken.FirstOrDefaultAsync(t => t.MemberID == request.MemberID && t.Provider == "YouTube", ct);

        if (oauthToken is not null)
        {
            // Google OAuth revoke (실패해도 무시)
            await oauthService.RevokeTokenAsync(oauthToken.AccessTokenEnc, ct);
            db.MemberOAuthToken.Remove(oauthToken);
        }

        // 채널 비활성화
        channel.Deactivate();

        // Redis 캐시 삭제
        var cacheKey = channel.YouTubeChannelID ?? channel.SID;
        await channelCache.RemoveAsync(cacheKey);

        await db.SaveChangesAsync(ct);

        // PubSub 구독 해지 (실패해도 DB는 이미 해지됨)
        if (!string.IsNullOrEmpty(channel.YouTubeChannelID))
        {
            try
            {
                await pubSubService.UnsubscribeAsync(channel.YouTubeChannelID, ct);
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "[DisconnectYouTube] PubSub 구독 해지 중 예외: channelId={ChannelId}", channel.YouTubeChannelID);
            }
        }

        logger.LogInformation("YouTube 연동 해지: MemberID={MemberID}, ChannelID={ChannelID}", request.MemberID, channel.ID);

        return Result.Success();
    }
}