Add SteamController implementation

This adds a Steam Shortcuts, Desktop Mode, and X360 Emulation
- Supports all Steam Shortcuts (including on-screen keyboard, and brightness)
- Supports Desktop mode (with a scroll on left pad and left stick), and trackpoint (on right stick)
- Supports X360 mode: hold Options for 1s to switch between Desktop and X360
- Holding Steam button enables Desktop like controls and stops passing all inputs to X360

SteamController/Controller.cs

@@ -0,0 +1,131 @@
+using CommonHelpers;
+using ExternalHelpers;
+using SteamController.Profiles;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+
+namespace SteamController
+{
+    internal class Controller : IDisposable
+    {
+        public const String Title = "Steam Controller";
+        public readonly String TitleWithVersion = Title + " v" + Application.ProductVersion.ToString();
+
+        Container components = new Container();
+        NotifyIcon notifyIcon;
+        StartupManager startupManager = new StartupManager(Title);
+
+        Context context;
+        Thread? contextThread;
+        bool running = true;
+
+        [DllImport("sas.dll")]
+        static extern void SendSAS(bool asUser);
+
+        public Controller()
+        {
+            Instance.RunOnce(TitleWithVersion, "Global\\SteamController");
+
+            SendSAS(true);
+
+            context = new Context()
+            {
+                Profiles = {
+                    new Profiles.SteamShortcutsProfile(),
+                    new Profiles.DesktopProfile(),
+                    new Profiles.X360Profile(),
+                    new Profiles.DebugProfile()
+                }
+            };
+
+            var contextMenu = new ContextMenuStrip(components);
+
+            if (startupManager.IsAvailable)
+            {
+                var startupItem = new ToolStripMenuItem("Run On Startup");
+                startupItem.Checked = startupManager.Startup;
+                startupItem.Click += delegate
+                {
+                    startupManager.Startup = !startupManager.Startup;
+                    startupItem.Checked = startupManager.Startup;
+                };
+                contextMenu.Items.Add(startupItem);
+            }
+
+            var helpItem = contextMenu.Items.Add("&Help");
+            helpItem.Click += delegate
+            {
+                System.Diagnostics.Process.Start("explorer.exe", "http://github.com/ayufan-research/steam-deck-tools");
+            };
+
+            contextMenu.Items.Add(new ToolStripSeparator());
+
+            var exitItem = contextMenu.Items.Add("&Exit");
+            exitItem.Click += delegate
+            {
+                Application.Exit();
+            };
+
+            notifyIcon = new NotifyIcon(components);
+            notifyIcon.Icon = Resources.microsoft_xbox_controller_off;
+            notifyIcon.Text = TitleWithVersion;
+            notifyIcon.Visible = true;
+            notifyIcon.ContextMenuStrip = contextMenu;
+
+            var contextStateUpdate = new System.Windows.Forms.Timer(components);
+            contextStateUpdate.Interval = 250;
+            contextStateUpdate.Enabled = true;
+            contextStateUpdate.Tick += ContextStateUpdate_Tick;
+
+            contextThread = new Thread(ContextState_Update);
+            contextThread.Start();
+        }
+
+        private void ContextState_Update(object? obj)
+        {
+            while (running)
+            {
+                context.Update();
+            }
+        }
+
+        private void ContextStateUpdate_Tick(object? sender, EventArgs e)
+        {
+            context.X360.CreateClient();
+
+            if (!context.Mouse.Valid)
+            {
+                notifyIcon.Text = TitleWithVersion + ". Cannot send input";
+                notifyIcon.Icon = Resources.microsoft_xbox_controller_off_red;
+            }
+            else if (!context.X360.Valid)
+            {
+                notifyIcon.Text = TitleWithVersion + ". Missing ViGEm?";
+                notifyIcon.Icon = Resources.microsoft_xbox_controller_red;
+            }
+            else if (context.DesktopMode)
+            {
+                notifyIcon.Icon = Resources.microsoft_xbox_controller_off;
+                notifyIcon.Text = TitleWithVersion + ". Desktop mode";
+            }
+            else
+            {
+                notifyIcon.Icon = Resources.microsoft_xbox_controller;
+                notifyIcon.Text = TitleWithVersion;
+            }
+        }
+
+        public void Dispose()
+        {
+            running = false;
+
+            if (contextThread != null)
+            {
+                contextThread.Interrupt();
+                contextThread.Join();
+            }
+
+            using (context) { }
+        }
+    }
+}