Initialize Windows desktop skeleton

WirelessTextSyncer.Windows/Services/IKeyboardInjectionService.cs

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+namespace WirelessTextSyncer.Windows.Services;
+
+public interface IKeyboardInjectionService
+{
+    void InsertText(string text);
+
+    void Backspace();
+
+    void Enter();
+}

WirelessTextSyncer.Windows/Services/KeyboardInjectionService.cs

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+namespace WirelessTextSyncer.Windows.Services;
+
+public sealed class KeyboardInjectionService : IKeyboardInjectionService
+{
+    public void InsertText(string text)
+    {
+        if (string.IsNullOrEmpty(text))
+        {
+            return;
+        }
+
+        SendKeys.SendWait(text);
+    }
+
+    public void Backspace()
+    {
+        SendKeys.SendWait("{BACKSPACE}");
+    }
+
+    public void Enter()
+    {
+        SendKeys.SendWait("{ENTER}");
+    }
+}

WirelessTextSyncer.Windows/Services/SyncMessageHandler.cs

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+using WirelessTextSyncer.Windows.Models;
+
+namespace WirelessTextSyncer.Windows.Services;
+
+public sealed class SyncMessageHandler
+{
+    private readonly IKeyboardInjectionService keyboard;
+
+    public SyncMessageHandler(IKeyboardInjectionService keyboard)
+    {
+        this.keyboard = keyboard;
+    }
+
+    public void Handle(SyncMessage message)
+    {
+        switch (message.Action)
+        {
+            case SyncAction.InsertText:
+                keyboard.InsertText(message.Text ?? string.Empty);
+                break;
+            case SyncAction.Backspace:
+                keyboard.Backspace();
+                break;
+            case SyncAction.Enter:
+                keyboard.Enter();
+                break;
+            case SyncAction.Ping:
+                break;
+            default:
+                throw new InvalidOperationException($"Unsupported sync action: {message.Action}");
+        }
+    }
+}

WirelessTextSyncer.Windows/Services/WebSocketServerService.cs

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+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+using Fleck;
+using WirelessTextSyncer.Windows.Models;
+
+namespace WirelessTextSyncer.Windows.Services;
+
+public sealed class WebSocketServerService : IDisposable
+{
+    private readonly SyncMessageHandler messageHandler;
+    private readonly List<IWebSocketConnection> clients = [];
+    private WebSocketServer? server;
+
+    public WebSocketServerService(SyncMessageHandler messageHandler)
+    {
+        this.messageHandler = messageHandler;
+    }
+
+    public int Port { get; private set; } = 8181;
+
+    public string LocalIpAddress { get; private set; } = "127.0.0.1";
+
+    public bool HasClient => clients.Count > 0;
+
+    public event EventHandler? StatusChanged;
+
+    public void Start(int port)
+    {
+        Port = port;
+        LocalIpAddress = ResolveLocalIpAddress();
+
+        server = new WebSocketServer($"ws://0.0.0.0:{Port}");
+        server.Start(socket =>
+        {
+            socket.OnOpen = () =>
+            {
+                clients.Add(socket);
+                StatusChanged?.Invoke(this, EventArgs.Empty);
+            };
+            socket.OnClose = () =>
+            {
+                clients.Remove(socket);
+                StatusChanged?.Invoke(this, EventArgs.Empty);
+            };
+            socket.OnMessage = HandleRawMessage;
+        });
+    }
+
+    public void Dispose()
+    {
+        foreach (var client in clients.ToArray())
+        {
+            client.Close();
+        }
+
+        clients.Clear();
+        server?.Dispose();
+    }
+
+    private void HandleRawMessage(string rawMessage)
+    {
+        var message = JsonSerializer.Deserialize<SyncMessage>(rawMessage);
+        if (message is null)
+        {
+            return;
+        }
+
+        messageHandler.Handle(message);
+    }
+
+    private static string ResolveLocalIpAddress()
+    {
+        var host = Dns.GetHostEntry(Dns.GetHostName());
+        var address = host.AddressList.FirstOrDefault(
+            address => address.AddressFamily == AddressFamily.InterNetwork
+                && !IPAddress.IsLoopback(address));
+
+        return address?.ToString() ?? "127.0.0.1";
+    }
+}