protected override async Task <JobResult> ProcessQueueEntryAsync(JobQueueEntryContext <EventNotificationWorkItem> context)
        {
            var eventModel = await _eventRepository.GetByIdAsync(context.QueueEntry.Value.EventId).AnyContext();

            if (eventModel == null)
            {
                return(JobResult.FailedWithMessage($"Could not load event: {context.QueueEntry.Value.EventId}"));
            }

            var  eventNotification = new EventNotification(context.QueueEntry.Value, eventModel);
            bool shouldLog         = eventNotification.Event.ProjectId != Settings.Current.InternalProjectId;
            int  emailsSent        = 0;

            Logger.Trace().Message("Process notification: project={0} event={1} stack={2}", eventNotification.Event.ProjectId, eventNotification.Event.Id, eventNotification.Event.StackId).WriteIf(shouldLog);

            var project = await _projectRepository.GetByIdAsync(eventNotification.Event.ProjectId, true).AnyContext();

            if (project == null)
            {
                return(JobResult.FailedWithMessage($"Could not load project: {eventNotification.Event.ProjectId}."));
            }
            Logger.Trace().Message($"Loaded project: name={project.Name}").WriteIf(shouldLog);

            var organization = await _organizationRepository.GetByIdAsync(project.OrganizationId, true).AnyContext();

            if (organization == null)
            {
                return(JobResult.FailedWithMessage($"Could not load organization: {project.OrganizationId}"));
            }

            Logger.Trace().Message($"Loaded organization: {organization.Name}").WriteIf(shouldLog);

            var stack = await _stackRepository.GetByIdAsync(eventNotification.Event.StackId).AnyContext();

            if (stack == null)
            {
                return(JobResult.FailedWithMessage($"Could not load stack: {eventNotification.Event.StackId}"));
            }

            if (!organization.HasPremiumFeatures)
            {
                Logger.Info().Message("Skipping \"{0}\" because organization \"{1}\" does not have premium features.", eventNotification.Event.Id, eventNotification.Event.OrganizationId).WriteIf(shouldLog);
                return(JobResult.Success);
            }

            if (stack.DisableNotifications || stack.IsHidden)
            {
                Logger.Info().Message("Skipping \"{0}\" because stack \"{1}\" notifications are disabled or stack is hidden.", eventNotification.Event.Id, eventNotification.Event.StackId).WriteIf(shouldLog);
                return(JobResult.Success);
            }

            if (context.CancellationToken.IsCancellationRequested)
            {
                return(JobResult.Cancelled);
            }

            Logger.Trace().Message("Loaded stack: title={0}", stack.Title).WriteIf(shouldLog);
            int totalOccurrences = stack.TotalOccurrences;

            // after the first 2 occurrences, don't send a notification for the same stack more then once every 30 minutes
            var lastTimeSentUtc = await _cacheClient.GetAsync <DateTime>(String.Concat("notify:stack-throttle:", eventNotification.Event.StackId), DateTime.MinValue).AnyContext();

            if (totalOccurrences > 2 &&
                !eventNotification.IsRegression &&
                lastTimeSentUtc != DateTime.MinValue &&
                lastTimeSentUtc > DateTime.UtcNow.AddMinutes(-30))
            {
                Logger.Info().Message("Skipping message because of stack throttling: last sent={0} occurrences={1}", lastTimeSentUtc, totalOccurrences).WriteIf(shouldLog);
                return(JobResult.Success);
            }

            // don't send more than 10 notifications for a given project every 30 minutes
            var    projectTimeWindow = TimeSpan.FromMinutes(30);
            string cacheKey          = String.Concat("notify:project-throttle:", eventNotification.Event.ProjectId, "-", DateTime.UtcNow.Floor(projectTimeWindow).Ticks);
            long   notificationCount = await _cacheClient.IncrementAsync(cacheKey, 1, projectTimeWindow).AnyContext();

            if (notificationCount > 10 && !eventNotification.IsRegression)
            {
                Logger.Info().Project(eventNotification.Event.ProjectId).Message("Skipping message because of project throttling: count={0}", notificationCount).WriteIf(shouldLog);
                return(JobResult.Success);
            }

            if (context.CancellationToken.IsCancellationRequested)
            {
                return(JobResult.Cancelled);
            }

            foreach (var kv in project.NotificationSettings)
            {
                var settings = kv.Value;
                Logger.Trace().Message("Processing notification: user={0}", kv.Key).WriteIf(shouldLog);

                var user = await _userRepository.GetByIdAsync(kv.Key).AnyContext();

                if (String.IsNullOrEmpty(user?.EmailAddress))
                {
                    Logger.Error().Message("Could not load user {0} or blank email address {1}.", kv.Key, user != null ? user.EmailAddress : "").Write();
                    continue;
                }

                if (!user.IsEmailAddressVerified)
                {
                    Logger.Info().Message("User {0} with email address {1} has not been verified.", kv.Key, user != null ? user.EmailAddress : "").WriteIf(shouldLog);
                    continue;
                }

                if (!user.EmailNotificationsEnabled)
                {
                    Logger.Info().Message("User {0} with email address {1} has email notifications disabled.", kv.Key, user != null ? user.EmailAddress : "").WriteIf(shouldLog);
                    continue;
                }

                if (!user.OrganizationIds.Contains(project.OrganizationId))
                {
                    Logger.Error().Message("Unauthorized user: project={0} user={1} organization={2} event={3}", project.Id, kv.Key, project.OrganizationId, eventNotification.Event.Id).Write();
                    continue;
                }

                Logger.Trace().Message("Loaded user: email={0}", user.EmailAddress).WriteIf(shouldLog);

                bool shouldReportNewError      = settings.ReportNewErrors && eventNotification.IsNew && eventNotification.Event.IsError();
                bool shouldReportCriticalError = settings.ReportCriticalErrors && eventNotification.IsCritical && eventNotification.Event.IsError();
                bool shouldReportRegression    = settings.ReportEventRegressions && eventNotification.IsRegression;
                bool shouldReportNewEvent      = settings.ReportNewEvents && eventNotification.IsNew;
                bool shouldReportCriticalEvent = settings.ReportCriticalEvents && eventNotification.IsCritical;
                bool shouldReport = shouldReportNewError || shouldReportCriticalError || shouldReportRegression || shouldReportNewEvent || shouldReportCriticalEvent;

                Logger.Trace().Message("Settings: newerror={0} criticalerror={1} regression={2} new={3} critical={4}",
                                       settings.ReportNewErrors, settings.ReportCriticalErrors,
                                       settings.ReportEventRegressions, settings.ReportNewEvents, settings.ReportCriticalEvents).WriteIf(shouldLog);
                Logger.Trace().Message("Should process: newerror={0} criticalerror={1} regression={2} new={3} critical={4}",
                                       shouldReportNewError, shouldReportCriticalError,
                                       shouldReportRegression, shouldReportNewEvent, shouldReportCriticalEvent).WriteIf(shouldLog);

                var request = eventNotification.Event.GetRequestInfo();
                // check for known bots if the user has elected to not report them
                if (shouldReport && !String.IsNullOrEmpty(request?.UserAgent))
                {
                    var botPatterns = project.Configuration.Settings.ContainsKey(SettingsDictionary.KnownKeys.UserAgentBotPatterns)
                        ? project.Configuration.Settings.GetStringCollection(SettingsDictionary.KnownKeys.UserAgentBotPatterns).ToList()
                        : new List <string>();

                    var info = await _parser.ParseAsync(request.UserAgent, eventNotification.Event.ProjectId).AnyContext();

                    if (info != null && info.Device.IsSpider || request.UserAgent.AnyWildcardMatches(botPatterns))
                    {
                        shouldReport = false;
                        Logger.Info().Message("Skipping because event is from a bot \"{0}\".", request.UserAgent).WriteIf(shouldLog);
                    }
                }

                if (!shouldReport)
                {
                    continue;
                }

                var model = new EventNotificationModel(eventNotification)
                {
                    ProjectName      = project.Name,
                    TotalOccurrences = totalOccurrences
                };

                // don't send notifications in non-production mode to email addresses that are not on the outbound email list.
                if (Settings.Current.WebsiteMode != WebsiteMode.Production &&
                    !Settings.Current.AllowedOutboundAddresses.Contains(v => user.EmailAddress.ToLowerInvariant().Contains(v)))
                {
                    Logger.Info().Message("Skipping because email is not on the outbound list and not in production mode.").WriteIf(shouldLog);
                    continue;
                }

                Logger.Trace().Message("Sending email to {0}...", user.EmailAddress).Write();
                await _mailer.SendNoticeAsync(user.EmailAddress, model).AnyContext();

                emailsSent++;
                Logger.Trace().Message("Done sending email.").WriteIf(shouldLog);
            }

            // if we sent any emails, mark the last time a notification for this stack was sent.
            if (emailsSent > 0)
            {
                await _cacheClient.SetAsync(String.Concat("notify:stack-throttle:", eventNotification.Event.StackId), DateTime.UtcNow, DateTime.UtcNow.AddMinutes(15)).AnyContext();

                Logger.Info().Message("Notifications sent: event={0} stack={1} count={2}", eventNotification.Event.Id, eventNotification.Event.StackId, emailsSent).WriteIf(shouldLog);
            }

            return(JobResult.Success);
        }