improve network log support

Application/IO/NetworkLogState.cs

@@ -0,0 +1,138 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+
+namespace IW4MAdmin.Application.IO;
+
+public class NetworkLogState : Dictionary<IPEndPoint, UdpClientState>
+{
+    public UdpClientState RegisterEndpoint(IPEndPoint serverEndpoint, IPEndPoint localEndpoint)
+    {
+        try
+        {
+            lock (this)
+            {
+                if (!ContainsKey(serverEndpoint))
+                {
+                    Add(serverEndpoint, new UdpClientState { Client = new UdpClient(localEndpoint) });
+                }
+            }
+        }
+        catch (SocketException ex) when (ex.SocketErrorCode == SocketError.AddressAlreadyInUse)
+        {
+            lock (this)
+            {
+                // we don't add the udp client because it already exists (listening to multiple servers from one socket)
+                Add(serverEndpoint,  new UdpClientState());
+            }
+        }
+
+        return this[serverEndpoint];
+    }
+
+
+    public List<byte[]> GetServerLogData(IPEndPoint serverEndpoint)
+    {
+        try
+        {
+            var state = this[serverEndpoint];
+            
+            if (state == null)
+            {
+                return new List<byte[]>();
+            }
+            
+            // it's possible that we could be trying to read and write to the queue simultaneously so we need to wait 
+            this[serverEndpoint].OnAction.Wait();
+
+            var data = new List<byte[]>();
+            
+            while (this[serverEndpoint].AvailableLogData.Count > 0)
+            {
+                data.Add(this[serverEndpoint].AvailableLogData.Dequeue());
+            }
+           
+            return data;
+        }
+        finally
+        {
+            if (this[serverEndpoint].OnAction.CurrentCount == 0)
+            {
+                this[serverEndpoint].OnAction.Release(1);
+            }
+        }
+    }
+
+    public void QueueServerLogData(IPEndPoint serverEndpoint, byte[] data)
+    {
+        var endpoint = Keys.FirstOrDefault(key =>
+            Equals(key.Address, serverEndpoint.Address) && key.Port == serverEndpoint.Port);
+
+        try
+        {
+            if (endpoint == null)
+            {
+                return;
+            }
+
+            // currently our expected start and end characters
+            var startsWithPrefix = StartsWith(data, "ÿÿÿÿprint\n");
+            var endsWithDelimiter = data[^1] == '\n';
+
+            // we have the data we expected
+            if (!startsWithPrefix || !endsWithDelimiter)
+            {
+                return;
+            }
+
+            // it's possible that we could be trying to read and write to the queue simultaneously so we need to wait 
+            this[endpoint].OnAction.Wait();
+            this[endpoint].AvailableLogData.Enqueue(data);
+        }
+        finally
+        {
+            if (endpoint != null && this[endpoint].OnAction.CurrentCount == 0)
+            {
+                this[endpoint].OnAction.Release(1);
+            }
+        }
+    }
+
+    public bool EndPointExists(IPEndPoint serverEndpoint)
+    {
+        lock (this)
+        {
+            return ContainsKey(serverEndpoint);
+        }
+    }
+
+    private static bool StartsWith(byte[] sourceArray, string match)
+    {
+        if (sourceArray is null)
+        {
+            return false;
+        }
+        
+        if (match.Length > sourceArray.Length)
+        {
+            return false;
+        }
+
+        return !match.Where((t, i) => sourceArray[i] != (byte)t).Any();
+    }
+}
+
+public class UdpClientState
+{
+    public UdpClient Client { get; set; }
+    public Queue<byte[]> AvailableLogData { get; } = new();
+    public SemaphoreSlim OnAction { get; } = new(1, 1);
+
+    ~UdpClientState()
+    {
+        OnAction.Dispose();
+        Client?.Dispose();
+    }
+}