Implement alt to toggle to previous window(s)

DD2Switcher/DD2Switcher.csproj

@@ -57,6 +57,7 @@
       <DependentUpon>Form1.cs</DependentUpon>
     </Compile>
     <Compile Include="HotKeyManager.cs" />
+    <Compile Include="KeyboardHook.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <EmbeddedResource Include="Properties\Resources.resx">

DD2Switcher/KeyboardHook.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Diagnostics;
+using System.Windows.Forms;
+using System.Runtime.InteropServices;
+
+class KeyboardHook {
+    private const int WH_KEYBOARD_LL = 13;
+    private const int WM_KEYDOWN = 0x0104;
+    private const int WM_KEYUP = 0x0101;
+    private static LowLevelKeyboardProc _proc = HookCallback;
+    private static IntPtr _hookID = IntPtr.Zero;
+
+    public static int previousEvent = 0;
+    public static event EventHandler<int> KeyDown;
+    public static event EventHandler<int> KeyUp;
+
+    public static void Start() {
+        _hookID = SetHook(_proc);
+    }
+
+    public static void Stop() {
+        UnhookWindowsHookEx(_hookID);
+    }
+
+    private static IntPtr SetHook(LowLevelKeyboardProc proc) {
+        using (Process curProcess = Process.GetCurrentProcess()) using (ProcessModule curModule =
+                                                                            curProcess.MainModule) {
+            return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
+        }
+    }
+
+    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
+
+    private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam) {
+        if (nCode >= 0) {
+            int vkCode = Marshal.ReadInt32(lParam);
+            int pero = (int)wParam * 1000 + vkCode;
+            if (pero != previousEvent) {
+                if (wParam == (IntPtr)WM_KEYDOWN) {
+                    KeyDown?.Invoke(null, vkCode);
+                } else if (wParam == (IntPtr)WM_KEYUP) {
+                    KeyUp?.Invoke(null, vkCode);
+                }
+                previousEvent = pero;
+            } else {
+                Console.WriteLine("Same event");
+            }
+        }
+        return CallNextHookEx(_hookID, nCode, wParam, lParam);
+    }
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    [return:MarshalAs(UnmanagedType.Bool)]
+    private static extern bool UnhookWindowsHookEx(IntPtr hhk);
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
+
+    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr GetModuleHandle(string lpModuleName);
+}

DD2Switcher/Program.cs

@@ -13,10 +13,10 @@ namespace DD2Switcher {
         private static int ActiveIndex = -1;
         private static int PreviousIndex = -1;
         private static bool AltPressed = false;
-        private static Timer AltTimer;
 
         private static readonly IntPtr defaultAffinity = new(0xFF000000);
         private static readonly IntPtr fullAffinity = new(0xFFFFFFFF);
+        private static readonly KeyboardHook keyboardHook = new();
 
         [DllImport("user32.dll")]
         public static extern IntPtr GetForegroundWindow();
@@ -151,6 +151,7 @@ namespace DD2Switcher {
             Console.WriteLine($"Added {process.ProcessName} to tracked windows at index {firstNullIndex}");
         }
 
+        // TODO: Restore this
         // private static void TrackWows() {
         //   CleanWindows();
         //   var processes = Process.GetProcesses().OrderBy(p => p.Id).ToList();
@@ -257,14 +258,6 @@ namespace DD2Switcher {
             }
         }
 
-        private static void OnAltTimer() {
-            if (AltPressed) {
-                AltPressed = false;
-                AltTimer.Stop();
-                TabToPrevious();
-            }
-        }
-
         private static bool IsCapsLockOn() {
             return (GetKeyState(0x14) & 1) == 1;
         }
@@ -282,10 +275,28 @@ namespace DD2Switcher {
                     Process.GetCurrentProcess().Kill();
                 }
 
-            AltTimer = new Timer(OnAltTimer, null, Timeout.Infinite, Timeout.Infinite);
+            bool onlyAlt = false;
+            KeyboardHook.Start();
+            KeyboardHook.KeyDown += (sender, e) => {
+                Console.WriteLine($"Key down: {e}");
+                if (e == 164 && !onlyAlt) {
+                    Console.WriteLine("Only alt");
+                    onlyAlt = true;
+                } else {
+                    Console.WriteLine("Not only alt");
+                    onlyAlt = false;
+                }
+            };
+            KeyboardHook.KeyUp += (sender, e) => {
+                Console.WriteLine($"Key up: {e}");
+                if (e == 164 && onlyAlt) {  // Left alt
+                    Console.WriteLine("Tab to previous");
+                    onlyAlt = false;
+                    TabToPrevious();
+                }
+            };
 
             HotKeyManager.RegisterHotKey(Keys.Capital, KeyModifiers.NoRepeat);
-            HotKeyManager.RegisterHotKey(Keys.Menu, KeyModifiers.NoRepeat);
             // Register main number keys (0-9)
             for (int i = 0; i < 10; i++) HotKeyManager.RegisterHotKey(Keys.D0 + i, KeyModifiers.Alt);
 
@@ -301,17 +312,6 @@ namespace DD2Switcher {
                 //   return;
                 // }
 
-                if (e.Key == Keys.Menu && e.Modifiers == KeyModifiers.NoRepeat) {
-                    AltPressed = true;
-                    AltTimer.Change(150, Timeout.Infinite);
-                    return;
-                }
-
-                if (e.Modifiers == KeyModifiers.Alt) {
-                    AltPressed = false;
-                    AltTimer.Stop();
-                }
-
                 int index;
                 if (e.Key >= Keys.D0 && e.Key <= Keys.D9) {
                     index = e.Key - Keys.D0;
@@ -330,8 +330,9 @@ namespace DD2Switcher {
                 }
             }
 
-            Console.CancelKeyPress += (sender, e) => { Process.GetCurrentProcess().Kill(); };
+            // Console.CancelKeyPress += (sender, e) => { Process.GetCurrentProcess().Kill(); };
-            while (true) System.Threading.Thread.Sleep(100000);
+            Application.Run();
+            KeyboardHook.Stop();
         }
     }
 }