Radicade Public Code

Server/Chat/RecentImageReferences.cs

@@ -0,0 +1,46 @@
+using System.Collections.Concurrent;
+
+namespace RadicadeServer.API
+{
+	public static class RecentImageReferences
+	{
+		public static readonly TimeSpan Window = TimeSpan.FromMinutes(10);
+
+		private sealed record Lookup(long ImageId, DateTime At);
+
+		private static readonly ConcurrentDictionary<long, Lookup> ByPlayer = new();
+
+		public static void Remember(long accountId, long imageId)
+			=> Remember(accountId, imageId, DateTime.UtcNow);
+
+		public static void Remember(long accountId, long imageId, DateTime at)
+		{
+			if (accountId <= 0 || imageId <= 0) return;
+
+			Prune(at);
+			ByPlayer[accountId] = new Lookup(imageId, at);
+		}
+
+		public static bool TryGet(long accountId, out long imageId)
+		{
+			imageId = 0;
+			if (accountId <= 0) return false;
+			if (!ByPlayer.TryGetValue(accountId, out var lookup)) return false;
+			if (DateTime.UtcNow - lookup.At > Window) return false;
+
+			imageId = lookup.ImageId;
+			return true;
+		}
+
+		public static void Clear() => ByPlayer.Clear();
+
+		private static void Prune(DateTime now)
+		{
+			foreach (var pair in ByPlayer)
+			{
+				if (now - pair.Value.At > Window)
+					ByPlayer.TryRemove(pair.Key, out _);
+			}
+		}
+	}
+}