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Femto.Modules.Media/Infrastructure/Integration/Mailman.cs

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+using System.Text.Json;
+using Femto.Modules.Media.Data;
+using MediatR;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace Femto.Modules.Media.Infrastructure.Integration;
+
+internal class Mailman(Outbox outbox, MediaContext context, ILogger<Mailman> logger, IMediator mediator)
+    : BackgroundService
+{
+    protected override async Task ExecuteAsync(CancellationToken cancellationToken)
+    {
+        var timeToWait = TimeSpan.FromSeconds(1);
+
+        while (!cancellationToken.IsCancellationRequested)
+        {
+            try
+            {
+                await this.DeliverMail(cancellationToken);
+            }
+            catch (Exception e)
+            {
+                logger.LogError(e, "Error while processing outbox");
+            }
+
+            try
+            {
+                await Task.Delay(timeToWait, cancellationToken);
+            }
+            catch (TaskCanceledException)
+            {
+                break;
+            }
+        }
+    }
+
+    private async Task DeliverMail(CancellationToken cancellationToken)
+    {
+        var messages = await outbox.GetPendingMessages(cancellationToken);
+
+        foreach (var message in messages)
+        {
+            try
+            {
+                var notificationType = OutboxMessageTypeRegistry.GetType(message.EventType);
+                if (notificationType is null)
+                {
+                    logger.LogWarning("unmapped event type {Type}. skipping.", message.EventType);
+                    continue;
+                }
+
+                var notification =
+                    JsonSerializer.Deserialize(message.Payload, notificationType) as INotification;
+
+                if (notification is null)
+                    throw new Exception("notification is null");
+
+                await mediator.Publish(notification, cancellationToken);
+
+                message.Succeed();
+            }
+            catch (Exception e)
+            {
+                logger.LogError(
+                    e,
+                    "Error processing event {EventId} for aggregate {AggregateId}",
+                    message.Id,
+                    message.AggregateId
+                );
+
+                message.Fail(e.ToString());
+            }
+
+            await context.SaveChangesAsync(cancellationToken);
+        }
+    }
+}