Add desktop diagnostics and resilient message handling

WirelessTextSyncer.Windows/Services/AppLogger.cs

@@ -0,0 +1,32 @@
+namespace WirelessTextSyncer.Windows.Services;
+
+public static class AppLogger
+{
+    private static readonly object SyncRoot = new();
+    private static readonly string LogDirectory = Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+        "WirelessTextSyncer");
+
+    public static string LogPath => Path.Combine(LogDirectory, "desktop.log");
+
+    public static void Info(string message)
+    {
+        Write("INFO", message);
+    }
+
+    public static void Error(string message, Exception? exception = null)
+    {
+        Write("ERROR", exception is null ? message : $"{message}{Environment.NewLine}{exception}");
+    }
+
+    private static void Write(string level, string message)
+    {
+        lock (SyncRoot)
+        {
+            Directory.CreateDirectory(LogDirectory);
+            File.AppendAllText(
+                LogPath,
+                $"{DateTimeOffset.Now:yyyy-MM-dd HH:mm:ss.fff zzz} [{level}] {message}{Environment.NewLine}");
+        }
+    }
+}

WirelessTextSyncer.Windows/Services/KeyboardInjectionService.cs

@@ -17,6 +17,7 @@ public sealed class KeyboardInjectionService : IKeyboardInjectionService
             return;
         }
 
+        AppLogger.Info($"Injecting text length: {text.Length}");
         foreach (var character in text)
         {
             SendUnicode(character);
@@ -25,11 +26,13 @@ public sealed class KeyboardInjectionService : IKeyboardInjectionService
 
     public void Backspace()
     {
+        AppLogger.Info("Injecting backspace.");
         SendVirtualKey(VirtualKeyBack);
     }
 
     public void Enter()
     {
+        AppLogger.Info("Injecting enter.");
         SendVirtualKey(VirtualKeyReturn);
     }
 
@@ -54,7 +57,9 @@ public sealed class KeyboardInjectionService : IKeyboardInjectionService
         var sent = SendInput((uint)inputs.Length, inputs, Marshal.SizeOf<INPUT>());
         if (sent != inputs.Length)
         {
-            throw new InvalidOperationException("Windows did not accept all keyboard input events.");
+            var error = Marshal.GetLastWin32Error();
+            AppLogger.Error(
+                $"Windows accepted {sent}/{inputs.Length} keyboard input events. Win32 error: {error}");
         }
     }
 

WirelessTextSyncer.Windows/Services/WebSocketServerService.cs

@@ -1,4 +1,5 @@
 using System.Net;
+using System.Net.NetworkInformation;
 using System.Net.Sockets;
 using System.Text.Json;
 using Fleck;
@@ -44,6 +45,7 @@ public sealed class WebSocketServerService : IDisposable
     {
         Port = port;
         LocalIpAddress = ResolveLocalIpAddress();
+        AppLogger.Info($"Starting WebSocket server on 0.0.0.0:{Port}. Local IP: {LocalIpAddress}");
 
         server = new WebSocketServer($"ws://0.0.0.0:{Port}");
         server.Start(socket =>
@@ -55,6 +57,7 @@ public sealed class WebSocketServerService : IDisposable
                     clients.Add(socket);
                 }
 
+                AppLogger.Info($"Client connected: {socket.ConnectionInfo.ClientIpAddress}:{socket.ConnectionInfo.ClientPort}");
                 StatusChanged?.Invoke(this, EventArgs.Empty);
             };
             socket.OnClose = () =>
@@ -64,6 +67,12 @@ public sealed class WebSocketServerService : IDisposable
                     clients.Remove(socket);
                 }
 
+                AppLogger.Info($"Client disconnected: {socket.ConnectionInfo.ClientIpAddress}:{socket.ConnectionInfo.ClientPort}");
+                StatusChanged?.Invoke(this, EventArgs.Empty);
+            };
+            socket.OnError = exception =>
+            {
+                AppLogger.Error("WebSocket connection error.", exception);
                 StatusChanged?.Invoke(this, EventArgs.Empty);
             };
             socket.OnMessage = HandleRawMessage;
@@ -91,26 +100,42 @@ public sealed class WebSocketServerService : IDisposable
     {
         try
         {
+            AppLogger.Info($"Received message: {rawMessage}");
             var message = JsonSerializer.Deserialize<SyncMessage>(rawMessage, JsonOptions);
             if (message is null)
             {
+                AppLogger.Info("Ignored empty sync message.");
                 return;
             }
 
             messageHandler.Handle(message);
         }
-        catch (JsonException)
+        catch (JsonException exception)
         {
-            return;
+            AppLogger.Error($"Invalid sync message: {rawMessage}", exception);
+        }
+        catch (Exception exception)
+        {
+            AppLogger.Error($"Failed to handle sync message: {rawMessage}", exception);
         }
     }
 
     private static string ResolveLocalIpAddress()
     {
-        var host = Dns.GetHostEntry(Dns.GetHostName());
+        var address = NetworkInterface.GetAllNetworkInterfaces()
-        var address = host.AddressList.FirstOrDefault(
+            .Where(networkInterface =>
-            address => address.AddressFamily == AddressFamily.InterNetwork
+                networkInterface.OperationalStatus == OperationalStatus.Up
-                && !IPAddress.IsLoopback(address));
+                && networkInterface.NetworkInterfaceType != NetworkInterfaceType.Loopback)
+            .Select(networkInterface => networkInterface.GetIPProperties())
+            .Where(properties => properties.GatewayAddresses.Any(
+                gateway => gateway.Address.AddressFamily == AddressFamily.InterNetwork
+                    && !IPAddress.Any.Equals(gateway.Address)))
+            .SelectMany(properties => properties.UnicastAddresses)
+            .Select(unicast => unicast.Address)
+            .FirstOrDefault(address =>
+                address.AddressFamily == AddressFamily.InterNetwork
+                && !IPAddress.IsLoopback(address)
+                && !address.ToString().StartsWith("169.254.", StringComparison.Ordinal));
 
         return address?.ToString() ?? "127.0.0.1";
     }

WirelessTextSyncer.Windows/Tray/TrayApplicationContext.cs

@@ -9,6 +9,7 @@ public sealed class TrayApplicationContext : ApplicationContext
 
     public TrayApplicationContext()
     {
+        AppLogger.Info("Tray application starting.");
         var keyboard = new KeyboardInjectionService();
         var handler = new SyncMessageHandler(keyboard);
 
@@ -31,6 +32,7 @@ public sealed class TrayApplicationContext : ApplicationContext
         }
         catch (Exception ex)
         {
+            AppLogger.Error("Failed to start tray application.", ex);
             notifyIcon.BalloonTipTitle = "WirelessTextSyncer";
             notifyIcon.BalloonTipText = $"Failed to start: {ex.Message}";
             notifyIcon.ShowBalloonTip(5000);