Ignore desktop language service caches

.gitignore

@@ -5,6 +5,6 @@ obj/
 *.user
 *.suo
 *.log
+*.lscache
 .env
 .env.*
-

WirelessTextSyncer.Desktop.sln

@@ -5,6 +5,8 @@ VisualStudioVersion = 17.0.31903.59
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WirelessTextSyncer.Windows", "WirelessTextSyncer.Windows\WirelessTextSyncer.Windows.csproj", "{7AD6081A-F4EB-45AA-917B-2CCFA54E0A67}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WirelessTextSyncer.Windows.Tests", "WirelessTextSyncer.Windows.Tests\WirelessTextSyncer.Windows.Tests.csproj", "{FD53F0F1-EAE0-4CB2-9AC8-57797F0B95D1}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -18,5 +20,9 @@ Global
 		{7AD6081A-F4EB-45AA-917B-2CCFA54E0A67}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7AD6081A-F4EB-45AA-917B-2CCFA54E0A67}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7AD6081A-F4EB-45AA-917B-2CCFA54E0A67}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FD53F0F1-EAE0-4CB2-9AC8-57797F0B95D1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FD53F0F1-EAE0-4CB2-9AC8-57797F0B95D1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FD53F0F1-EAE0-4CB2-9AC8-57797F0B95D1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FD53F0F1-EAE0-4CB2-9AC8-57797F0B95D1}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

WirelessTextSyncer.Windows.Tests/SyncMessageTests.cs

@@ -0,0 +1,86 @@
+using System.Text.Json;
+using WirelessTextSyncer.Windows.Models;
+using WirelessTextSyncer.Windows.Services;
+
+namespace WirelessTextSyncer.Windows.Tests;
+
+[TestClass]
+public sealed class SyncMessageTests
+{
+    [TestMethod]
+    public void DeserializeAndroidInsertTextMessage()
+    {
+        var message = JsonSerializer.Deserialize<SyncMessage>(
+            """{"action":"insertText","text":"hello"}""",
+            new JsonSerializerOptions(JsonSerializerDefaults.Web));
+
+        Assert.IsNotNull(message);
+        Assert.AreEqual(SyncAction.InsertText, message.Action);
+        Assert.AreEqual("hello", message.Text);
+    }
+
+    [TestMethod]
+    public void DeserializeAndroidBackspaceMessage()
+    {
+        var message = JsonSerializer.Deserialize<SyncMessage>(
+            """{"action":"backspace"}""",
+            new JsonSerializerOptions(JsonSerializerDefaults.Web));
+
+        Assert.IsNotNull(message);
+        Assert.AreEqual(SyncAction.Backspace, message.Action);
+    }
+
+    [TestMethod]
+    public void DeserializeAndroidReplaceAllMessage()
+    {
+        var message = JsonSerializer.Deserialize<SyncMessage>(
+            """{"action":"replaceAll","text":"final text"}""",
+            new JsonSerializerOptions(JsonSerializerDefaults.Web));
+
+        Assert.IsNotNull(message);
+        Assert.AreEqual(SyncAction.ReplaceAll, message.Action);
+        Assert.AreEqual("final text", message.Text);
+    }
+
+    [TestMethod]
+    public void ReplaceAllAppendsSubmittedText()
+    {
+        var keyboard = new RecordingKeyboardInjectionService();
+        var handler = new SyncMessageHandler(keyboard);
+
+        handler.Handle(new SyncMessage
+        {
+            Action = SyncAction.ReplaceAll,
+            Text = "final text"
+        });
+
+        CollectionAssert.AreEqual(
+            new[] { "insert:final text" },
+            keyboard.Calls);
+    }
+
+    private sealed class RecordingKeyboardInjectionService : IKeyboardInjectionService
+    {
+        public List<string> Calls { get; } = [];
+
+        public void InsertText(string text)
+        {
+            Calls.Add($"insert:{text}");
+        }
+
+        public void ReplaceFocusedText(string text)
+        {
+            Calls.Add($"replace:{text}");
+        }
+
+        public void Backspace()
+        {
+            Calls.Add("backspace");
+        }
+
+        public void Enter()
+        {
+            Calls.Add("enter");
+        }
+    }
+}

WirelessTextSyncer.Windows.Tests/WirelessTextSyncer.Windows.Tests.csproj

@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0-windows</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="3.1.1" />
+    <PackageReference Include="MSTest.TestFramework" Version="3.1.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\WirelessTextSyncer.Windows\WirelessTextSyncer.Windows.csproj" />
+  </ItemGroup>
+
+</Project>

WirelessTextSyncer.Windows/Models/SyncAction.cs

@@ -1,8 +1,12 @@
 namespace WirelessTextSyncer.Windows.Models;
 
+using System.Text.Json.Serialization;
+
+[JsonConverter(typeof(SyncActionJsonConverter))]
 public enum SyncAction
 {
     InsertText,
+    ReplaceAll,
     Backspace,
     Enter,
     Ping

WirelessTextSyncer.Windows/Models/SyncActionJsonConverter.cs

@@ -0,0 +1,43 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace WirelessTextSyncer.Windows.Models;
+
+public sealed class SyncActionJsonConverter : JsonConverter<SyncAction>
+{
+    public override SyncAction Read(
+        ref Utf8JsonReader reader,
+        Type typeToConvert,
+        JsonSerializerOptions options)
+    {
+        var value = reader.GetString();
+
+        return value switch
+        {
+            "insertText" => SyncAction.InsertText,
+            "replaceAll" => SyncAction.ReplaceAll,
+            "backspace" => SyncAction.Backspace,
+            "enter" => SyncAction.Enter,
+            "ping" => SyncAction.Ping,
+            _ => throw new JsonException($"Unsupported sync action: {value}")
+        };
+    }
+
+    public override void Write(
+        Utf8JsonWriter writer,
+        SyncAction value,
+        JsonSerializerOptions options)
+    {
+        var action = value switch
+        {
+            SyncAction.InsertText => "insertText",
+            SyncAction.ReplaceAll => "replaceAll",
+            SyncAction.Backspace => "backspace",
+            SyncAction.Enter => "enter",
+            SyncAction.Ping => "ping",
+            _ => throw new JsonException($"Unsupported sync action: {value}")
+        };
+
+        writer.WriteStringValue(action);
+    }
+}

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/IKeyboardInjectionService.cs

@@ -4,6 +4,8 @@ public interface IKeyboardInjectionService
 {
     void InsertText(string text);
 
+    void ReplaceFocusedText(string text);
+
     void Backspace();
 
     void Enter();

WirelessTextSyncer.Windows/Services/KeyboardInjectionService.cs

@@ -1,7 +1,29 @@
 namespace WirelessTextSyncer.Windows.Services;
 
+using System.Runtime.InteropServices;
+
+public enum TextInjectionMode
+{
+    ClipboardPaste,
+    SendInputTyping
+}
+
 public sealed class KeyboardInjectionService : IKeyboardInjectionService
 {
+    private const uint InputKeyboard = 1;
+    private const uint KeyEventFKeyUp = 0x0002;
+    private const uint KeyEventFUnicode = 0x0004;
+    private const uint KlfActivate = 0x00000001;
+    private const uint WmInputLangChangeRequest = 0x0050;
+    private const ushort VirtualKeyA = 0x41;
+    private const ushort VirtualKeyBack = 0x08;
+    private const ushort VirtualKeyControl = 0x11;
+    private const ushort VirtualKeyReturn = 0x0D;
+    private const ushort VirtualKeyV = 0x56;
+    private static readonly IntPtr EnglishKeyboardLayout = LoadKeyboardLayout("00000409", KlfActivate);
+
+    public TextInjectionMode Mode { get; set; } = TextInjectionMode.ClipboardPaste;
+
     public void InsertText(string text)
     {
         if (string.IsNullOrEmpty(text))
@@ -9,16 +31,289 @@ public sealed class KeyboardInjectionService : IKeyboardInjectionService
             return;
         }
 
-        SendKeys.SendWait(text);
+        AppLogger.Info($"Inserting text length: {text.Length}. Mode: {Mode}.");
+        if (Mode == TextInjectionMode.SendInputTyping)
+        {
+            TypeTextWithSendInput(text);
+            return;
+        }
+
+        PasteTextViaClipboard(text);
+    }
+
+    private static void TypeTextWithSendInput(string text)
+    {
+        AppLogger.Info($"Falling back to SendInput text length: {text.Length}");
+        using var keyboardLayoutScope = KeyboardLayoutScope.SwitchForegroundWindowToEnglish();
+        foreach (var character in text)
+        {
+            AppLogger.Info($"Injecting char U+{(int)character:X4}: {character}");
+            SendUnicode(character);
+            Thread.Sleep(2);
+        }
+    }
+
+    private static void PasteTextViaClipboard(string text)
+    {
+        Exception? failure = null;
+        var thread = new Thread(() =>
+        {
+            try
+            {
+                PasteTextOnStaThread(text);
+            }
+            catch (Exception ex)
+            {
+                failure = ex;
+            }
+        });
+
+        thread.SetApartmentState(ApartmentState.STA);
+        thread.Start();
+        thread.Join();
+
+        if (failure is not null)
+        {
+            AppLogger.Error("Clipboard paste failed.", failure);
+            TypeTextWithSendInput(text);
+        }
+    }
+
+    private static void PasteTextOnStaThread(string text)
+    {
+        var hadText = Clipboard.ContainsText(TextDataFormat.UnicodeText);
+        var previousText = hadText ? Clipboard.GetText(TextDataFormat.UnicodeText) : null;
+
+        try
+        {
+            Clipboard.SetText(text, TextDataFormat.UnicodeText);
+            Thread.Sleep(30);
+            SendModifiedKey(VirtualKeyControl, VirtualKeyV);
+            Thread.Sleep(150);
+        }
+        finally
+        {
+            RestoreClipboardText(hadText, previousText);
+        }
+    }
+
+    private static void RestoreClipboardText(bool hadText, string? previousText)
+    {
+        try
+        {
+            if (hadText && previousText is not null)
+            {
+                Clipboard.SetText(previousText, TextDataFormat.UnicodeText);
+                return;
+            }
+
+            Clipboard.Clear();
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Error("Failed to restore clipboard text.", ex);
+        }
+    }
+
+    public void ReplaceFocusedText(string text)
+    {
+        AppLogger.Info($"Replacing focused text length: {text.Length}");
+        SendModifiedKey(VirtualKeyControl, VirtualKeyA);
+        Backspace();
+        InsertText(text);
+        AppLogger.Info("Finished replacing focused text.");
     }
 
     public void Backspace()
     {
-        SendKeys.SendWait("{BACKSPACE}");
+        AppLogger.Info("Injecting backspace.");
+        SendVirtualKey(VirtualKeyBack);
     }
 
     public void Enter()
     {
-        SendKeys.SendWait("{ENTER}");
+        AppLogger.Info("Injecting enter.");
+        SendVirtualKey(VirtualKeyReturn);
+    }
+
+    private static void SendUnicode(char character)
+    {
+        Send([
+            CreateUnicodeInput(character, 0),
+            CreateUnicodeInput(character, KeyEventFKeyUp)
+        ]);
+    }
+
+    private static void SendVirtualKey(ushort virtualKey)
+    {
+        Send([
+            CreateVirtualKeyInput(virtualKey, 0),
+            CreateVirtualKeyInput(virtualKey, KeyEventFKeyUp)
+        ]);
+    }
+
+    private static void SendModifiedKey(ushort modifierKey, ushort key)
+    {
+        Send([
+            CreateVirtualKeyInput(modifierKey, 0),
+            CreateVirtualKeyInput(key, 0),
+            CreateVirtualKeyInput(key, KeyEventFKeyUp),
+            CreateVirtualKeyInput(modifierKey, KeyEventFKeyUp)
+        ]);
+    }
+
+    private static void Send(INPUT[] inputs)
+    {
+        var sent = SendInput((uint)inputs.Length, inputs, Marshal.SizeOf<INPUT>());
+        if (sent != inputs.Length)
+        {
+            var error = Marshal.GetLastWin32Error();
+            AppLogger.Error(
+                $"Windows accepted {sent}/{inputs.Length} keyboard input events. Win32 error: {error}");
+        }
+    }
+
+    private static INPUT CreateUnicodeInput(char character, uint flags)
+    {
+        return new INPUT
+        {
+            type = InputKeyboard,
+            U = new InputUnion
+            {
+                ki = new KEYBDINPUT
+                {
+                    wScan = character,
+                    dwFlags = KeyEventFUnicode | flags
+                }
+            }
+        };
+    }
+
+    private static INPUT CreateVirtualKeyInput(ushort virtualKey, uint flags)
+    {
+        return new INPUT
+        {
+            type = InputKeyboard,
+            U = new InputUnion
+            {
+                ki = new KEYBDINPUT
+                {
+                    wVk = virtualKey,
+                    dwFlags = flags
+                }
+            }
+        };
+    }
+
+    [DllImport("user32.dll", SetLastError = true)]
+    private static extern uint SendInput(uint numberOfInputs, INPUT[] inputs, int sizeOfInputStructure);
+
+    [DllImport("user32.dll")]
+    private static extern IntPtr GetForegroundWindow();
+
+    [DllImport("user32.dll")]
+    private static extern uint GetWindowThreadProcessId(IntPtr windowHandle, out uint processId);
+
+    [DllImport("user32.dll")]
+    private static extern IntPtr GetKeyboardLayout(uint threadId);
+
+    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
+    private static extern IntPtr LoadKeyboardLayout(string keyboardLayoutId, uint flags);
+
+    [DllImport("user32.dll", SetLastError = true)]
+    private static extern bool PostMessage(IntPtr windowHandle, uint message, IntPtr wParam, IntPtr lParam);
+
+    private sealed class KeyboardLayoutScope : IDisposable
+    {
+        private readonly IntPtr foregroundWindow;
+        private readonly IntPtr originalKeyboardLayout;
+
+        private KeyboardLayoutScope(IntPtr foregroundWindow, IntPtr originalKeyboardLayout)
+        {
+            this.foregroundWindow = foregroundWindow;
+            this.originalKeyboardLayout = originalKeyboardLayout;
+        }
+
+        public static KeyboardLayoutScope SwitchForegroundWindowToEnglish()
+        {
+            var foregroundWindow = GetForegroundWindow();
+            if (foregroundWindow == IntPtr.Zero)
+            {
+                AppLogger.Error("Cannot switch keyboard layout because no foreground window was found.");
+                return new KeyboardLayoutScope(IntPtr.Zero, IntPtr.Zero);
+            }
+
+            var threadId = GetWindowThreadProcessId(foregroundWindow, out _);
+            var originalKeyboardLayout = GetKeyboardLayout(threadId);
+            AppLogger.Info($"Switching foreground keyboard layout from 0x{originalKeyboardLayout.ToInt64():X} to 0x{EnglishKeyboardLayout.ToInt64():X}.");
+
+            if (EnglishKeyboardLayout != IntPtr.Zero)
+            {
+                PostMessage(foregroundWindow, WmInputLangChangeRequest, IntPtr.Zero, EnglishKeyboardLayout);
+                Thread.Sleep(50);
+            }
+
+            return new KeyboardLayoutScope(foregroundWindow, originalKeyboardLayout);
+        }
+
+        public void Dispose()
+        {
+            if (foregroundWindow == IntPtr.Zero || originalKeyboardLayout == IntPtr.Zero)
+            {
+                return;
+            }
+
+            AppLogger.Info($"Restoring foreground keyboard layout to 0x{originalKeyboardLayout.ToInt64():X}.");
+            PostMessage(foregroundWindow, WmInputLangChangeRequest, IntPtr.Zero, originalKeyboardLayout);
+        }
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct INPUT
+    {
+        public uint type;
+        public InputUnion U;
+    }
+
+    [StructLayout(LayoutKind.Explicit)]
+    private struct InputUnion
+    {
+        [FieldOffset(0)]
+        public MOUSEINPUT mi;
+
+        [FieldOffset(0)]
+        public KEYBDINPUT ki;
+
+        [FieldOffset(0)]
+        public HARDWAREINPUT hi;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct MOUSEINPUT
+    {
+        public int dx;
+        public int dy;
+        public uint mouseData;
+        public uint dwFlags;
+        public uint time;
+        public UIntPtr dwExtraInfo;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct KEYBDINPUT
+    {
+        public ushort wVk;
+        public ushort wScan;
+        public uint dwFlags;
+        public uint time;
+        public UIntPtr dwExtraInfo;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct HARDWAREINPUT
+    {
+        public uint uMsg;
+        public ushort wParamL;
+        public ushort wParamH;
     }
 }

WirelessTextSyncer.Windows/Services/SyncMessageHandler.cs

@@ -5,6 +5,7 @@ namespace WirelessTextSyncer.Windows.Services;
 public sealed class SyncMessageHandler
 {
     private readonly IKeyboardInjectionService keyboard;
+    private string remoteText = string.Empty;
 
     public SyncMessageHandler(IKeyboardInjectionService keyboard)
     {
@@ -16,13 +17,24 @@ public sealed class SyncMessageHandler
         switch (message.Action)
         {
             case SyncAction.InsertText:
-                keyboard.InsertText(message.Text ?? string.Empty);
+                var insertedText = message.Text ?? string.Empty;
+                keyboard.InsertText(insertedText);
+                remoteText += insertedText;
+                break;
+            case SyncAction.ReplaceAll:
+                AppendSubmittedText(message.Text ?? string.Empty);
                 break;
             case SyncAction.Backspace:
                 keyboard.Backspace();
+                if (remoteText.Length > 0)
+                {
+                    remoteText = remoteText[..^1];
+                }
+
                 break;
             case SyncAction.Enter:
                 keyboard.Enter();
+                remoteText += Environment.NewLine;
                 break;
             case SyncAction.Ping:
                 break;
@@ -30,4 +42,16 @@ public sealed class SyncMessageHandler
                 throw new InvalidOperationException($"Unsupported sync action: {message.Action}");
         }
     }
+
+    private void AppendSubmittedText(string text)
+    {
+        if (string.IsNullOrEmpty(text))
+        {
+            return;
+        }
+
+        AppLogger.Info($"Appending submitted text length: {text.Length}");
+        keyboard.InsertText(text);
+        remoteText += text;
+    }
 }

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;
@@ -8,8 +9,14 @@ namespace WirelessTextSyncer.Windows.Services;
 
 public sealed class WebSocketServerService : IDisposable
 {
+    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web)
+    {
+        PropertyNameCaseInsensitive = true
+    };
+
     private readonly SyncMessageHandler messageHandler;
     private readonly List<IWebSocketConnection> clients = [];
+    private readonly object clientsLock = new();
     private WebSocketServer? server;
 
     public WebSocketServerService(SyncMessageHandler messageHandler)
@@ -21,7 +28,16 @@ public sealed class WebSocketServerService : IDisposable
 
     public string LocalIpAddress { get; private set; } = "127.0.0.1";
 
-    public bool HasClient => clients.Count > 0;
+    public bool HasClient
+    {
+        get
+        {
+            lock (clientsLock)
+            {
+                return clients.Count > 0;
+            }
+        }
+    }
 
     public event EventHandler? StatusChanged;
 
@@ -29,18 +45,34 @@ 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($"ws://0.0.0.0:{Port}");
         server.Start(socket =>
         {
             socket.OnOpen = () =>
+            {
+                lock (clientsLock)
                 {
                     clients.Add(socket);
+                }
+
+                AppLogger.Info($"Client connected: {socket.ConnectionInfo.ClientIpAddress}:{socket.ConnectionInfo.ClientPort}");
                 StatusChanged?.Invoke(this, EventArgs.Empty);
             };
             socket.OnClose = () =>
+            {
+                lock (clientsLock)
                 {
                     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;
@@ -49,32 +81,61 @@ public sealed class WebSocketServerService : IDisposable
 
     public void Dispose()
     {
-        foreach (var client in clients.ToArray())
+        IWebSocketConnection[] currentClients;
+        lock (clientsLock)
+        {
+            currentClients = clients.ToArray();
+            clients.Clear();
+        }
+
+        foreach (var client in currentClients)
         {
             client.Close();
         }
 
-        clients.Clear();
         server?.Dispose();
     }
 
     private void HandleRawMessage(string rawMessage)
     {
-        var message = JsonSerializer.Deserialize<SyncMessage>(rawMessage);
+        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 exception)
+        {
+            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

@@ -4,12 +4,16 @@ namespace WirelessTextSyncer.Windows.Tray;
 
 public sealed class TrayApplicationContext : ApplicationContext
 {
+    private readonly KeyboardInjectionService keyboard;
     private readonly WebSocketServerService server;
     private readonly NotifyIcon notifyIcon;
+    private ToolStripMenuItem? clipboardPasteMenuItem;
+    private ToolStripMenuItem? sendInputTypingMenuItem;
 
     public TrayApplicationContext()
     {
-        var keyboard = new KeyboardInjectionService();
+        AppLogger.Info("Tray application starting.");
+        keyboard = new KeyboardInjectionService();
         var handler = new SyncMessageHandler(keyboard);
 
         server = new WebSocketServerService(handler);
@@ -31,6 +35,7 @@ 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);
@@ -52,10 +57,60 @@ public sealed class TrayApplicationContext : ApplicationContext
     {
         var menu = new ContextMenuStrip();
         menu.Items.Add("Copy connection address", null, (_, _) => CopyConnectionAddress());
+        menu.Items.Add(BuildInputModeMenu());
         menu.Items.Add("Exit", null, (_, _) => ExitThread());
         return menu;
     }
 
+    private ToolStripMenuItem BuildInputModeMenu()
+    {
+        var inputModeMenu = new ToolStripMenuItem("Input mode");
+        clipboardPasteMenuItem = new ToolStripMenuItem("Clipboard paste")
+        {
+            CheckOnClick = false
+        };
+        sendInputTypingMenuItem = new ToolStripMenuItem("SendInput typing")
+        {
+            CheckOnClick = false
+        };
+
+        clipboardPasteMenuItem.Click += (_, _) => SetInputMode(TextInjectionMode.ClipboardPaste);
+        sendInputTypingMenuItem.Click += (_, _) => SetInputMode(TextInjectionMode.SendInputTyping);
+        inputModeMenu.DropDownItems.Add(clipboardPasteMenuItem);
+        inputModeMenu.DropDownItems.Add(sendInputTypingMenuItem);
+        UpdateInputModeMenuChecks();
+        return inputModeMenu;
+    }
+
+    private void SetInputMode(TextInjectionMode mode)
+    {
+        keyboard.Mode = mode;
+        AppLogger.Info($"Text injection mode changed to {mode}.");
+        UpdateInputModeMenuChecks();
+
+        notifyIcon.BalloonTipTitle = "WirelessTextSyncer";
+        notifyIcon.BalloonTipText = $"Input mode: {GetInputModeLabel(mode)}";
+        notifyIcon.ShowBalloonTip(1500);
+    }
+
+    private void UpdateInputModeMenuChecks()
+    {
+        if (clipboardPasteMenuItem is not null)
+        {
+            clipboardPasteMenuItem.Checked = keyboard.Mode == TextInjectionMode.ClipboardPaste;
+        }
+
+        if (sendInputTypingMenuItem is not null)
+        {
+            sendInputTypingMenuItem.Checked = keyboard.Mode == TextInjectionMode.SendInputTyping;
+        }
+    }
+
+    private static string GetInputModeLabel(TextInjectionMode mode)
+    {
+        return mode == TextInjectionMode.ClipboardPaste ? "Clipboard paste" : "SendInput typing";
+    }
+
     private void OnTrayIconClicked(object? sender, MouseEventArgs e)
     {
         if (e.Button == MouseButtons.Left)
@@ -75,6 +130,7 @@ public sealed class TrayApplicationContext : ApplicationContext
     private void UpdateTrayText()
     {
         var status = server.HasClient ? "connected" : "waiting";
-        notifyIcon.Text = $"WirelessTextSyncer {server.LocalIpAddress}:{server.Port} ({status})";
+        var text = $"WirelessTextSyncer {server.LocalIpAddress}:{server.Port} ({status})";
+        notifyIcon.Text = text.Length > 63 ? text[..63] : text;
     }
 }

WirelessTextSyncer.Windows/WirelessTextSyncer.Windows.csproj

@@ -10,7 +10,6 @@
 
   <ItemGroup>
     <PackageReference Include="Fleck" Version="1.2.0" />
-    <PackageReference Include="InputSimulatorPlus" Version="1.0.7" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.8" />
   </ItemGroup>