Replace polling with push-based Telegram notification queue

RazorPagesMovie/Services/IContactMessageNotificationQueue.cs

@@ -0,0 +1,32 @@
+using System.Collections.Concurrent;
+using System.Threading.Channels;
+
+namespace RazorPagesMovie.Services;
+
+public interface IContactMessageNotificationQueue
+{
+    void Enqueue(Guid contactMessageId);
+
+    IAsyncEnumerable<Guid> DequeueAllAsync(CancellationToken cancellationToken);
+
+    void Release(Guid contactMessageId);
+}
+
+public class ContactMessageNotificationQueue : IContactMessageNotificationQueue
+{
+    private readonly Channel<Guid> _channel = Channel.CreateUnbounded<Guid>();
+    private readonly ConcurrentDictionary<Guid, byte> _inFlight = new();
+
+    public void Enqueue(Guid contactMessageId)
+    {
+        if (_inFlight.TryAdd(contactMessageId, 0))
+        {
+            _channel.Writer.TryWrite(contactMessageId);
+        }
+    }
+
+    public IAsyncEnumerable<Guid> DequeueAllAsync(CancellationToken cancellationToken) =>
+        _channel.Reader.ReadAllAsync(cancellationToken);
+
+    public void Release(Guid contactMessageId) => _inFlight.TryRemove(contactMessageId, out _);
+}