AcManager.LargeFilesSharing.GoogleDrive.GoogleDriveUploader.SignIn C# (CSharp) Method

        public override async Task SignIn(CancellationToken cancellation) {
            await Prepare(cancellation);
            if (IsReady && DateTime.Now < _authExpiration) return;

            var data = InternalUtils.GetGoogleDriveCredentials();
            var clientId = data.Item1.Substring(2);
            var clientSecret = data.Item2.Substring(2);

            var code = await GetAutenficationCode(clientId, cancellation);
            if (cancellation.IsCancellationRequested) return;

            if (code == null) {
                throw new UserCancelledException();
            }

            var response = await Request.Post<AuthResponse>(@"https://www.googleapis.com/oauth2/v4/token", new NameValueCollection {
                { @"code", code },
                { @"client_id", clientId },
                { @"client_secret", clientSecret },
                { @"redirect_uri", RedirectUrl },
                { @"grant_type", @"authorization_code" }
            }.GetQuery(), null, cancellation);
            if (cancellation.IsCancellationRequested) return;

            if (response == null) {
                throw new Exception(ToolsStrings.Uploader_CannotFinishAuthorization);
            }

            _authToken = response;
            _authExpiration = DateTime.Now + TimeSpan.FromSeconds(response.ExpiresIn) - TimeSpan.FromSeconds(20);
            ValuesStorage.SetEncrypted(KeyAuthToken, JsonConvert.SerializeObject(_authToken));
            ValuesStorage.Set(KeyAuthExpiration, _authExpiration);
            IsReady = true;
        }