Fix notification activation and calendar bootstrap flow

Wino.Mail.WinUI/Program.cs

@@ -13,38 +13,87 @@ namespace Wino.Mail.WinUI;
 
 public class Program
 {
+    private const string AppNotificationActivatedCommandLinePrefix = "----AppNotificationActivated:";
     private const string SingleInstanceKey = "WinoMailSingleInstance";
     private const string ForceAlternateModeSignalEventName = "Local\\WinoMailForceAlternateMode";
+    private const string MailHostRunningMutexName = "Local\\WinoMailMailHostRunning";
     private const int VkControl = 0x11;
 
     private static bool _forceAlternateModeOnLaunch;
     private static EventWaitHandle? _forceAlternateModeSignalHandle;
+    private static Mutex? _mailHostRunningMutex;
+    private static PendingBootstrapActivation? _pendingBootstrapActivation;
+    private static bool _hasDeferredAppNotificationStartup;
+    private static bool _shouldRegisterAppNotifications;
 
     [STAThread]
     static int Main(string[] args)
     {
         WinRT.ComWrappersSupport.InitializeComWrappers();
-        bool isRedirect = DecideRedirection();
+
+        if (TryCaptureCommandLineToastActivation(args))
+        {
+            _shouldRegisterAppNotifications = true;
+            EnsureMailHostRunningMutex();
+            StartApplication();
+            return 0;
+        }
+
+        var activationArgs = AppInstance.GetCurrent().GetActivatedEventArgs();
+        var shouldBootstrapCalendarEntry = CalendarEntryBootstrapActivation.ShouldBootstrapToMailHost(activationArgs);
+        _shouldRegisterAppNotifications = !shouldBootstrapCalendarEntry;
+
+        if (shouldBootstrapCalendarEntry && !IsMailHostRunning())
+        {
+            if (CalendarEntryBootstrapActivation.QueuePendingActivation(activationArgs) &&
+                CalendarEntryBootstrapActivation.LaunchMailHost())
+            {
+                return 0;
+            }
+
+            CalendarEntryBootstrapActivation.ClearPendingActivation();
+        }
+
+        _pendingBootstrapActivation = CalendarEntryBootstrapActivation.ConsumePendingActivation();
+        bool isRedirect = DecideRedirection(activationArgs);
 
         if (!isRedirect)
         {
-            Application.Start((p) =>
-            {
-                var context = new DispatcherQueueSynchronizationContext(
-                    DispatcherQueue.GetForCurrentThread());
-                SynchronizationContext.SetSynchronizationContext(context);
-                var app = new App();
-                _ = app.HandleInitialActivationAsync();
-            });
+            EnsureMailHostRunningMutex();
+            StartApplication();
         }
 
         return 0;
     }
 
-    private static bool DecideRedirection()
+    public static bool ShouldRegisterAppNotifications()
+        => _shouldRegisterAppNotifications;
+
+    internal static bool TryConsumeDeferredAppNotificationStartup()
+    {
+        if (!_hasDeferredAppNotificationStartup)
+            return false;
+
+        _hasDeferredAppNotificationStartup = false;
+        return true;
+    }
+
+    internal static bool TryConsumePendingBootstrapActivation(out PendingBootstrapActivation activation)
+    {
+        if (_pendingBootstrapActivation == null)
+        {
+            activation = null!;
+            return false;
+        }
+
+        activation = _pendingBootstrapActivation;
+        _pendingBootstrapActivation = null;
+        return true;
+    }
+
+    private static bool DecideRedirection(AppActivationArguments args)
     {
         bool isRedirect = false;
-        AppActivationArguments args = AppInstance.GetCurrent().GetActivatedEventArgs();
         _forceAlternateModeOnLaunch = args.Kind == ExtendedActivationKind.Launch && IsCtrlKeyDown();
 
         AppInstance keyInstance = AppInstance.FindOrRegisterForKey(SingleInstanceKey);
@@ -69,6 +118,60 @@ public class Program
         return isRedirect;
     }
 
+    private static bool TryCaptureCommandLineToastActivation(string[] args)
+    {
+        var commandLine = Environment.CommandLine;
+        var prefixIndex = commandLine.IndexOf(AppNotificationActivatedCommandLinePrefix, StringComparison.OrdinalIgnoreCase);
+
+        if (prefixIndex < 0)
+            return false;
+
+        // Do not touch AppInstance.GetActivatedEventArgs here. For app-notification cold starts,
+        // Windows App SDK expects the app to register AppNotificationManager first and then
+        // resolve the activation inside App.OnLaunched.
+        _hasDeferredAppNotificationStartup = true;
+        return true;
+    }
+
+    private static void StartApplication()
+    {
+        Application.Start((p) =>
+        {
+            var context = new DispatcherQueueSynchronizationContext(
+                DispatcherQueue.GetForCurrentThread());
+            SynchronizationContext.SetSynchronizationContext(context);
+            _ = new App();
+        });
+    }
+
+    private static bool IsMailHostRunning()
+    {
+        try
+        {
+            if (!Mutex.TryOpenExisting(MailHostRunningMutexName, out var existingMutex))
+                return false;
+
+            existingMutex.Dispose();
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static void EnsureMailHostRunningMutex()
+    {
+        try
+        {
+            _mailHostRunningMutex ??= new Mutex(false, MailHostRunningMutexName);
+        }
+        catch
+        {
+            _mailHostRunningMutex = null;
+        }
+    }
+
     [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
     private static extern IntPtr CreateEvent(
         IntPtr lpEventAttributes, bool bManualReset,