ANTOOZA-BACKEND/Application/Features/Api/MyPage/Sns/Disconnect/Handler.cs

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

namespace Application.Features.Api.MyPage.Sns.Disconnect;

internal sealed class Handler(
    IAppDbContext db,
    IGoogleOAuthService oauthService,
    ILogger<Handler> logger
) : ICommandHandler<Command, Result<Response>>
{
    private static readonly string[] AllowedProviders = ["Google"];
    private static readonly TimeSpan RetryDelay = TimeSpan.FromMilliseconds(500);

    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        if (!AllowedProviders.Contains(request.Provider))
        {
            return Result.Failure<Response>(Error.Problem("Sns.UnsupportedProvider", "지원하지 않는 SNS provider 입니다."));
        }

        var token = await db.MemberOAuthToken.FirstOrDefaultAsync(t => t.MemberID == request.MemberID && t.Provider == request.Provider, ct);

        if (token is null)
        {
            // idempotent: 이미 연동되어 있지 않아도 성공으로 처리
            return Result.Success(new Response(request.Provider, true));
        }

        // Google revoke 시도 — refresh_token 우선 (refresh_token revoke 는 access_token 도 함께 무효화)
        var revokeTarget = !string.IsNullOrEmpty(token.RefreshTokenEnc)
            ? token.RefreshTokenEnc
            : token.AccessTokenEnc;

        var revoked = await oauthService.RevokeTokenAsync(revokeTarget, ct);

        if (!revoked)
        {
            // 1회 재시도 (네트워크 일시 장애/Google 5xx 대비)
            try
            {
                await Task.Delay(RetryDelay, ct);
                revoked = await oauthService.RevokeTokenAsync(revokeTarget, ct);
            }
            catch (OperationCanceledException)
            {
                throw;
            }
        }

        // DB 삭제 — revoke 성공/실패 무관 (DB 삭제는 항상 진행)
        db.MemberOAuthToken.Remove(token);
        await db.SaveChangesAsync(ct);

        if (!revoked)
        {
            logger.LogWarning("[Sns.Disconnect] revoke 실패 — DB 만 삭제. memberID={MemberID}, provider={Provider}", request.MemberID, request.Provider);
        }
        else
        {
            logger.LogInformation("[Sns.Disconnect] 연동 해제 완료: memberID={MemberID}, provider={Provider}", request.MemberID, request.Provider);
        }

        return Result.Success(new Response(request.Provider, revoked));
    }
}