using System;
using System.Drawing;
using System.Runtime.InteropServices;

// The 'windowHandle' parameter will contain the window handle for the:
//   - Active window when run by hotkey
//   - Window Location target when run by a Window Location rule
//   - TitleBar Button owner when run by a TitleBar Button
//   - Jump List owner when run from a Taskbar Jump List
//   - Currently focused window if none of these match
public static class DisplayFusionFunction
{
	//overload this function to take an unsigned integer as pvParam to set the mouse speed
	[DllImport("user32.dll", SetLastError = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	private static extern bool SystemParametersInfo(uint uiAction, uint uiParam, uint pvParam, uint fWinIni);
	
	//overload this function to output pvParam to an unsigned integer
	[DllImport("user32.dll", SetLastError = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	private static extern bool SystemParametersInfo(uint uiAction, uint uiParam, out uint pvParam, uint fWinIni);
	
	//constants to get and set the mouse speed
	private const uint SPI_GETMOUSESPEED = 0x0070;
	private const uint SPI_SETMOUSESPEED = 0x0071;
		
	//constants to tell windows to update profile and windows
	private const uint SPIF_UPDATEINIFILE = 0x0001;
	private const uint SPIF_SENDWININICHANGE = 0x0002;
	
	public static void Run(IntPtr windowHandle)
	{
		//initialize a uint
		uint speed = 0;
		
		//get the mouse speed
		SystemParametersInfo(SPI_GETMOUSESPEED, 0, out speed, 0);
		
		//decrement the mouse speed and set it
		SystemParametersInfo(SPI_SETMOUSESPEED, 0, --speed, SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE);
	}
}