Standalone Notifier IPC Subsystem

LocalTelemetry.Notifier is a standalone, lightweight WinForms executable (LocalTelemetry.Notifier.exe) targeting .NET 10 Windows x64. It is dedicated to rendering non-blocking desktop toast alert windows.

Why a Standalone Process?

Rendering alert windows with slide-in animations and auto-dismiss timers inside the main application process carries two key risks:

1. Focus Stealing: Window activation during full-screen gaming or video playback could cause games to minimize.
2. UI Thread Blocking: Animation loops on the main UI thread could delay telemetry sensor polling ticks.

By spinning up LocalTelemetry.Notifier.exe as a secondary process, notifications display smoothly without stealing foreground focus or blocking hardware monitoring threads.

📡 Named Pipe IPC Communication

LocalTelemetry.App launches LocalTelemetry.Notifier.exe passing its Parent Process ID (PID) as args[0]. Inter-process communication takes place over an asynchronous Windows Named Pipe (LocalTelemetryNotifier).

JSON Message Contract (NotificationMessage)

NotificationClient.cs serializes messages over the pipe in UTF-8 JSON Lines format:

{
  "Action": "ShowToast",
  "Title": "CPU Temperature Warning",
  "Body": "CPU reached 91°C (Limit: 90°C)"
}

internal sealed record NotificationMessage
{
    public string Action { get; set; } = string.Empty;
    public string? Title { get; set; }
    public string? Body { get; set; }
}

Command Actions

• ShowToast: Triggers ToastForm rendering on screen with Title and Body.
• Shutdown: Gracefully cancels CancellationTokenSource and closes HiddenForm.

🖥️ Hidden Message Pump (HiddenForm)

Inside Program.cs, an invisible HiddenForm provides a WinForms message pump:

• Hidden from Alt+Tab via WS_EX_TOOLWINDOW (0x00000080) extended window style.
• ShowInTaskbar = false, WindowState = Minimized, Opacity = 0.
• Receives pipe messages on a background thread (RunPipeServerAsync) and dispatches toast creation to the UI thread via hiddenForm.BeginInvoke(...).

🎨 Toast Window Rendering & Animation (ToastForm.cs)

ToastForm renders a custom dark alert window:

• Dimensions: 320px width × 90px height.
• Appearance: Dark background (Color.FromArgb(32, 32, 32)), rounded corners (CornerRadius = 8 via GraphicsPath), border pen (Color.FromArgb(60, 60, 60)).
• Audio Cue: Plays system asterisk sound (SystemSounds.Asterisk.Play()).
• Ease-Out Slide-In Animation: OnLoad animates the window position from below the screen working area using a cubic ease-out curve (1.0 - Math.Pow(1.0 - t, 3)) over 300ms.
• Auto-Dismiss: A System.Windows.Forms.Timer automatically closes the toast window after 5000ms.

🛡️ Parent Process Monitoring & Auto-Exit

When LocalTelemetry.Notifier.exe receives parentPid as args[0]:

1. Launches a background worker task: Process.GetProcessById(parentPid).WaitForExit().
2. When the parent LocalTelemetry.exe process exits, the notifier process automatically logs exit and shuts down cleanly.