TASK 20 step 1: global hotkeys F1-F9 (scenes, stream, mutes, TRAX)

Services/GlobalHotkeys.cs

@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using AppLog = ytLive.Helpers.AppLog;
+
+namespace ytLive.Services;
+
+public enum HotkeyId
+{
+    SceneStarting = 1,
+    SceneLive = 2,
+    SceneBrb = 3,
+    SceneChat = 4,
+    SceneEnding = 5,
+    StartStopStream = 6,
+    ToggleMicMute = 7,
+    ToggleGameMute = 8,
+    TraxPlayPause = 9,
+}
+
+/// <summary>Registers/revokes the OS-level hotkeys. Seam so tests never touch
+/// user32 (a real registration is global to the machine and needs a pump).</summary>
+public interface IHotkeyRegistrar
+{
+    bool Register(IntPtr hwnd, HotkeyId id, uint virtualKey);
+    void Unregister(IntPtr hwnd, HotkeyId id);
+}
+
+public sealed class Win32HotkeyRegistrar : IHotkeyRegistrar
+{
+    public bool Register(IntPtr hwnd, HotkeyId id, uint virtualKey)
+        => RegisterHotKey(hwnd, (int)id, 0, virtualKey);
+
+    public void Unregister(IntPtr hwnd, HotkeyId id)
+        => UnregisterHotKey(hwnd, (int)id);
+
+    [DllImport("user32.dll", SetLastError = true)]
+    private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);
+
+    [DllImport("user32.dll", SetLastError = true)]
+    private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
+}
+
+/// <summary>
+/// TASK 20: global hotkeys — work while the app is unfocused (streamers are in-game).
+/// Defaults: F1-F5 stage/transition the five canonical scenes, F6 start/end stream,
+/// F7 mute mic, F8 mute desktop audio, F9 TRAX play/pause.
+/// Attach after the window has a source (OnSourceInitialized); Detach on close.
+/// </summary>
+public sealed class GlobalHotkeyManager
+{
+    public const int WM_HOTKEY = 0x0312;
+
+    internal static Func<IHotkeyRegistrar>? RegistrarOverride;
+
+    private static readonly Dictionary<HotkeyId, uint> Defaults = new()
+    {
+        [HotkeyId.SceneStarting] = 0x70, // F1
+        [HotkeyId.SceneLive] = 0x71,     // F2
+        [HotkeyId.SceneBrb] = 0x72,      // F3
+        [HotkeyId.SceneChat] = 0x73,     // F4
+        [HotkeyId.SceneEnding] = 0x74,   // F5
+        [HotkeyId.StartStopStream] = 0x75, // F6
+        [HotkeyId.ToggleMicMute] = 0x76,   // F7
+        [HotkeyId.ToggleGameMute] = 0x77,  // F8
+        [HotkeyId.TraxPlayPause] = 0x78,   // F9
+    };
+
+    private readonly IHotkeyRegistrar _registrar;
+    private readonly List<HotkeyId> _registered = new();
+    private IntPtr _hwnd;
+    private System.Windows.Interop.HwndSource? _source;
+
+    /// <summary>Raised on the UI thread for each WM_HOTKEY that carries a known id.</summary>
+    public event Action<HotkeyId>? Activated;
+
+    public GlobalHotkeyManager()
+        : this(RegistrarOverride?.Invoke() ?? new Win32HotkeyRegistrar())
+    {
+    }
+
+    internal GlobalHotkeyManager(IHotkeyRegistrar registrar) => _registrar = registrar;
+
+    public void Attach(System.Windows.Window window)
+    {
+        _hwnd = new System.Windows.Interop.WindowInteropHelper(window).Handle;
+        _source = System.Windows.Interop.HwndSource.FromHwnd(_hwnd);
+        _source?.AddHook(WndProc);
+        foreach (var (id, vk) in Defaults)
+        {
+            if (_registrar.Register(_hwnd, id, vk))
+                _registered.Add(id);
+            else
+                AppLog.Write($"Hotkey: {(HotkeyId)id} (vk {vk}) not registered — likely owned by another app");
+        }
+        window.Closed += OnWindowClosed;
+        AppLog.Write($"hotkey: attached, {_registered.Count} registered");
+    }
+
+    private void OnWindowClosed(object? sender, EventArgs e) => Detach();
+
+    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
+    {
+        if (msg != WM_HOTKEY) return IntPtr.Zero;
+        var raw = wParam.ToInt64();
+        if (raw is < 1 or > int.MaxValue || !Enum.IsDefined(typeof(HotkeyId), (int)raw))
+            return IntPtr.Zero;
+        Activated?.Invoke((HotkeyId)raw);
+        handled = true;
+        return IntPtr.Zero;
+    }
+
+    private void Detach()
+    {
+        if (_hwnd != IntPtr.Zero)
+            foreach (var id in _registered)
+                _registrar.Unregister(_hwnd, id);
+        _registered.Clear();
+        _source?.RemoveHook(WndProc);
+        _source = null;
+        _hwnd = IntPtr.Zero;
+    }
+}