StayAwake.bat

<# ::
@@ start "" powershell -WindowStyle Hidden -NoProfile -ExecutionPolicy Bypass -Command "Invoke-Expression (Get-Content -Raw '%~f0')"
#>

$ErrorActionPreference = "Stop"
try {
Add-Type -Language CSharp -ReferencedAssemblies $("System.Windows.Forms", "System.Drawing") @"
using System;
using System.Drawing;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;

public class StayAwake : ApplicationContext {
	[FlagsAttribute]
	enum EXECUTION_STATE : uint {
		ES_AWAYMODE_REQUIRED = 0x00000040, // replace sleep (incl manual) with a fake-sleep where cpu is still active (doesn't affect display/idle timer)
		ES_CONTINUOUS        = 0x80000000, // continuously set
		ES_DISPLAY_REQUIRED  = 0x00000002, // display timer
		ES_SYSTEM_REQUIRED   = 0x00000001, // idle timer
	}

	[DllImport("kernel32.dll", CharSet = CharSet.Auto,SetLastError = true)]
	static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE esFlags);

	private NotifyIcon icon;
	private EXECUTION_STATE state = EXECUTION_STATE.ES_CONTINUOUS;

	StayAwake() {
		icon = new NotifyIcon() {
			Icon = Icon.ExtractAssociatedIcon("C:\\Windows\\System32\\msra.exe"),
			//Icon = Icon.ExtractAssociatedIcon(Application.ExecutablePath), // use /win32icon:whatever.ico when compiling
			ContextMenu = new ContextMenu(new MenuItem[] {
				new MenuItem("Disable &idle timer", Toggle(EXECUTION_STATE.ES_SYSTEM_REQUIRED)),
				new MenuItem("Keep &display on", Toggle(EXECUTION_STATE.ES_DISPLAY_REQUIRED)),
				new MenuItem("Replace &sleep", Toggle(EXECUTION_STATE.ES_AWAYMODE_REQUIRED)),
				new MenuItem("-"),
				new MenuItem("E&xit", Exit),
			}),
			Visible = true,
		};
		icon.MouseClick += (object sender, MouseEventArgs e) => {
			if (e.Button == MouseButtons.Left) {
				typeof(NotifyIcon).GetMethod("ShowContextMenu", BindingFlags.Instance | BindingFlags.NonPublic).Invoke(icon, null);
			}
		};
	}
	
	EventHandler Toggle(EXECUTION_STATE flag) {
		return (object sender, EventArgs e) => {
			SetThreadExecutionState(state ^= flag);
			((MenuItem) sender).Checked = state.HasFlag(flag);
			icon.Text = (state &~ EXECUTION_STATE.ES_CONTINUOUS).ToString();
		};
	}

	void Exit(object sender, EventArgs e) {
		icon.Visible = false;
		Application.Exit();
	}

	public static void Main() {
		Application.EnableVisualStyles();
		Application.SetCompatibleTextRenderingDefault(false);
		Application.Run(new StayAwake());
	}
}
"@
[StayAwake]::Main()
} catch {
Add-Type -AssemblyName System.Windows.Forms
[System.Windows.Forms.MessageBox]::Show($Error, "Error")
}