function Set-Association
{
	[CmdletBinding()]
	param
	(
		[Parameter(
			Position = 0,
			Mandatory = $true
		)]
		[ValidateScript({Test-Path -Path $_})]
		[String]
		$ProgramPath,

		[Parameter(
			Position = 1,
			Mandatory = $true
		)]
		[String]
		$Extension,

		[Parameter(
			Position = 3,
			Mandatory = $false
		)]
		[String]
		$Icon
	)

	$ProgId = "Applications\" + (Get-Item -Path $ProgramPath).BaseName + $Extension

	if (-not (Test-Path -Path "HKCU:\SOFTWARE\Classes\$Extension\OpenWithProgids"))
	{
		New-Item -Path "HKCU:\SOFTWARE\Classes\$Extension\OpenWithProgids" -Force
	}
	New-ItemProperty -Path "HKCU:\SOFTWARE\Classes\$Extension\OpenWithProgids" -Name $ProgId -PropertyType None -Value ([byte[]]@()) -Force

	if (-not (Test-Path -Path "HKCU:\SOFTWARE\Classes\$ProgId\shell\open\command"))
	{
		New-Item -Path "HKCU:\SOFTWARE\Classes\$ProgId\shell\open\command" -Force
	}
	New-ItemProperty -Path "HKCU:\SOFTWARE\Classes\$ProgId\shell\open\command" -Name "(Default)" -PropertyType String -Value "`"$ProgramPath`" `"%1`"" -Force

	function Set-FTA
	{
		[CmdletBinding()]
		param
		(
			[Parameter(Mandatory = $true)]
			[String]
			$ProgId,

			[Parameter(Mandatory = $true)]
			[String]
			$Extension,

			[String]
			$Icon
		)

		function local:Set-Icon
		{
			param
			(
				[Parameter(
					Position = 0,
					Mandatory = $true
				)]
				[String]
				$ProgId,

				[Parameter(
					Position = 1,
					Mandatory = $true
				)]
				[String]
				$Icon
			)

			if (-not (Test-Path -Path "HKCU:\SOFTWARE\Classes\$ProgId\DefaultIcon"))
			{
				New-Item -Path "HKCU:\SOFTWARE\Classes\$ProgId\DefaultIcon" -Force
			}
			New-ItemProperty -Path "HKCU:\SOFTWARE\Classes\$ProgId\DefaultIcon" -Name "(Default)" -PropertyType String -Value $Icon -Force
		}

		function local:Write-ExtensionKeys
		{
			param
			(
				[Parameter(
					Position = 0,
					Mandatory = $true
				)]
				[String]
				$ProgId,

				[Parameter(
					Position = 1,
					Mandatory = $true
				)]
				[String]
				$Extension,

				[Parameter(
					Position = 2,
					Mandatory = $true
				)]
				[String]
				$ProgHash
			)

			function local:Remove-UserChoiceKey
			{
				param
				(
					[Parameter(
						Position = 0,
						Mandatory = $true
					)]
					[String]
					$Key
				)

				$Signature = @{
					Namespace = "Registry"
					Name = "Utils"
					Language = "CSharp"
					MemberDefinition = @"
[DllImport("advapi32.dll", SetLastError = true)]
private static extern int RegOpenKeyEx(UIntPtr hKey, string subKey, int ulOptions, int samDesired, out UIntPtr hkResult);

[DllImport("advapi32.dll", SetLastError=true, CharSet = CharSet.Unicode)]
private static extern uint RegDeleteKey(UIntPtr hKey, string subKey);

public static void DeleteKey(string key)
{
	UIntPtr hKey = UIntPtr.Zero;
	RegOpenKeyEx((UIntPtr)0x80000001u, key, 0, 0x20019, out hKey);
	RegDeleteKey((UIntPtr)0x80000001u, key);
}
"@
				}

				if (-not ("Registry.Utils" -as [type]))
				{
					Add-Type @Signature
				}

				[Registry.Utils]::DeleteKey($Key)
			}

			Remove-UserChoiceKey -Key "Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\$Extension\UserChoice"

			if (-not (Test-Path -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\$Extension\UserChoice"))
			{
				New-Item -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\$Extension\UserChoice" -Force
			}
			New-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\$Extension\UserChoice" -Name Hash -PropertyType String -Value $ProgHash -Force
			New-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\$Extension\UserChoice" -Name ProgId -PropertyType String -Value $ProgId -Force
		}

		function local:Get-HexDateTime
		{
			[OutputType([string])]

			$now = [DateTime]::Now
			$dateTime = [DateTime]::New($now.Year, $now.Month, $now.Day, $now.Hour, $now.Minute, 0)
			$fileTime = $dateTime.ToFileTime()
			$hi = ($fileTime -shr 32)
			$low = ($fileTime -band 0xFFFFFFFFL)
			$dateTimeHex = ($hi.ToString("X8") + $low.ToString("X8")).ToLower()

			return $dateTimeHex
		}

		function Get-Hash
		{
			[CmdletBinding()]
			param
			(
				[Parameter(
					Position = 0,
					Mandatory = $true
				)]
				[string]
				$BaseInfo
			)

			function local:Get-ShiftRight
			{
				[CmdletBinding()]
				param
				(
					[Parameter(
						Position = 0,
						Mandatory = $true
					)]
					[long]
					$iValue,

					[Parameter(
						Position = 1,
						Mandatory = $true
					)]
					[int]
					$iCount
				)

				if ($iValue -band 0x80000000)
				{
					return (($iValue -shr $iCount) -bxor 0xFFFF0000)
				}
				else
				{
					return ($iValue -shr $iCount)
				}
			}

			function local:Get-Long
			{
				[CmdletBinding()]
				param
				(
					[Parameter(
						Position = 0,
						Mandatory = $true
					)]
					[byte[]]
					$Bytes,

					[Parameter(Position = 1)]
					[int]
					$Index = 0
				)

				return ([BitConverter]::ToInt32($Bytes, $Index))
			}

			function local:Convert-Int32
			{
				param
				(
					[Parameter(
						Position = 0,
						Mandatory = $true
					)]
					$Value
				)

				[byte[]]$bytes = [BitConverter]::GetBytes($Value)
				return [BitConverter]::ToInt32($bytes, 0)
			}

			[byte[]]$bytesBaseInfo = [System.Text.Encoding]::Unicode.GetBytes($baseInfo)
			$bytesBaseInfo += 0x00, 0x00

			$MD5 = New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
			[byte[]]$bytesMD5 = $MD5.ComputeHash($bytesBaseInfo)

			$lengthBase = ($baseInfo.Length * 2) + 2
			$length = (($lengthBase -band 4) -le 1) + (Get-ShiftRight -iValue $lengthBase -iCount 2) - 1
			$base64Hash = ""

			if ($length -gt 1)
			{
				$Map = @{
					PDATA = 0
					CACHE = 0
					COUNTER = 0
					INDEX = 0
					MD51 = 0
					MD52 = 0
					OUTHASH1 = 0
					OUTHASH2 = 0
					R0 = 0
					R1 = @(0, 0)
					R2 = @(0, 0)
					R3 = 0
					R4 = @(0, 0)
					R5 = @(0, 0)
					R6 = @(0, 0)
					R7 = @(0, 0)
				}

				$Map.CACHE = 0
				$Map.OUTHASH1 = 0
				$Map.PDATA = 0
				$Map.MD51 = (((Get-Long -Bytes $bytesMD5) -bor 1) + 0x69FB0000L)
				$Map.MD52 = ((Get-Long -Bytes $bytesMD5 -Index 4) -bor 1) + 0x13DB0000L
				$Map.INDEX = Get-ShiftRight -iValue ($length - 2) -iCount 1
				$Map.COUNTER = $Map.INDEX + 1

				while ($Map.COUNTER)
				{
					$Map.R0 = Convert-Int32 -Value ((Get-Long -Bytes $bytesBaseInfo -Index $Map.PDATA) + [long]$Map.OUTHASH1)
					$Map.R1[0] = Convert-Int32 -Value (Get-Long -Bytes $bytesBaseInfo -Index ($Map.PDATA + 4))
					$Map.PDATA = $Map.PDATA + 8
					$Map.R2[0] = Convert-Int32 -Value (($Map.R0 * ([long]$Map.MD51)) - (0x10FA9605L * ((Get-ShiftRight -iValue $Map.R0 -iCount 16))))
					$Map.R2[1] = Convert-Int32 -Value ((0x79F8A395L * ([long]$Map.R2[0])) + (0x689B6B9FL * (Get-ShiftRight -iValue $Map.R2[0] -iCount 16)))
					$Map.R3 = Convert-Int32 -Value ((0xEA970001L * $Map.R2[1]) - (0x3C101569L * (Get-ShiftRight -iValue $Map.R2[1] -iCount 16) ))
					$Map.R4[0] = Convert-Int32 -Value ($Map.R3 + $Map.R1[0])
					$Map.R5[0] = Convert-Int32 -Value ($Map.CACHE + $Map.R3)
					$Map.R6[0] = Convert-Int32 -Value (($Map.R4[0] * [long]$Map.MD52) - (0x3CE8EC25L * (Get-ShiftRight -iValue $Map.R4[0] -iCount 16)))
					$Map.R6[1] = Convert-Int32 -Value ((0x59C3AF2DL * $Map.R6[0]) - (0x2232E0F1L * (Get-ShiftRight -iValue $Map.R6[0] -iCount 16)))
					$Map.OUTHASH1 = Convert-Int32 -Value ((0x1EC90001L * $Map.R6[1]) + (0x35BD1EC9L * (Get-ShiftRight -iValue $Map.R6[1] -iCount 16)))
					$Map.OUTHASH2 = Convert-Int32 -Value ([long]$Map.R5[0] + [long]$Map.OUTHASH1)
					$Map.CACHE = ([long]$Map.OUTHASH2)
					$Map.COUNTER = $Map.COUNTER - 1
				}

				[byte[]] $outHash = @(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
				[byte[]] $buffer = [BitConverter]::GetBytes($Map.OUTHASH1)
				$buffer.CopyTo($outHash, 0)
				$buffer = [BitConverter]::GetBytes($Map.OUTHASH2)
				$buffer.CopyTo($outHash, 4)

				$Map = @{
					PDATA = 0
					CACHE = 0
					COUNTER = 0
					INDEX = 0
					MD51 = 0
					MD52 = 0
					OUTHASH1 = 0
					OUTHASH2 = 0
					R0 = 0
					R1 = @(0, 0)
					R2 = @(0, 0)
					R3 = 0
					R4 = @(0, 0)
					R5 = @(0, 0)
					R6 = @(0, 0)
					R7 = @(0, 0)
				}

				$Map.CACHE = 0
				$Map.OUTHASH1 = 0
				$Map.PDATA = 0
				$Map.MD51 = ((Get-Long -Bytes $bytesMD5) -bor 1)
				$Map.MD52 = ((Get-Long -Bytes $bytesMD5 4) -bor 1)
				$Map.INDEX = Get-ShiftRight -iValue ($length - 2) -iCount 1
				$Map.COUNTER = $Map.INDEX + 1

				while ($Map.COUNTER)
				{
					$Map.R0 = Convert-Int32 -Value ((Get-Long -Bytes $bytesBaseInfo -Index $Map.PDATA) + ([long]$Map.OUTHASH1))
					$Map.PDATA = $Map.PDATA + 8
					$Map.R1[0] = Convert-Int32 -Value ($Map.R0 * [long]$Map.MD51)
					$Map.R1[1] = Convert-Int32 -Value ((0xB1110000L * $Map.R1[0]) - (0x30674EEFL * (Get-ShiftRight -iValue $Map.R1[0] -iCount 16)))
					$Map.R2[0] = Convert-Int32 -Value ((0x5B9F0000L * $Map.R1[1]) - (0x78F7A461L * (Get-ShiftRight -iValue $Map.R1[1] -iCount 16)))
					$Map.R2[1] = Convert-Int32 -Value ((0x12CEB96DL * (Get-ShiftRight -iValue $Map.R2[0] 16)) - (0x46930000L * $Map.R2[0]))
					$Map.R3 = Convert-Int32 -Value ((0x1D830000L * $Map.R2[1]) + (0x257E1D83L * (Get-ShiftRight -iValue $Map.R2[1] -iCount 16)))
					$Map.R4[0] = Convert-Int32 -Value ([long]$Map.MD52 * ([long]$Map.R3 + (Get-Long -Bytes $bytesBaseInfo -Index ($Map.PDATA - 4))))
					$Map.R4[1] = Convert-Int32 -Value ((0x16F50000L * $Map.R4[0]) - (0x5D8BE90BL * (Get-ShiftRight -iValue $Map.R4[0] -iCount 16)))
					$Map.R5[0] = Convert-Int32 -Value ((0x96FF0000L * $Map.R4[1]) - (0x2C7C6901L * (Get-ShiftRight -iValue $Map.R4[1] -iCount 16)))
					$Map.R5[1] = Convert-Int32 -Value ((0x2B890000L * $Map.R5[0]) + (0x7C932B89L * (Get-ShiftRight -iValue $Map.R5[0] -iCount 16)))
					$Map.OUTHASH1 = Convert-Int32 -Value ((0x9F690000L * $Map.R5[1]) - (0x405B6097L * (Get-ShiftRight -iValue ($Map.R5[1]) -iCount 16)))
					$Map.OUTHASH2 = Convert-Int32 -Value ([long]$Map.OUTHASH1 + $Map.CACHE + $Map.R3)
					$Map.CACHE = ([long]$Map.OUTHASH2)
					$Map.COUNTER = $Map.COUNTER - 1
				}

				$buffer = [BitConverter]::GetBytes($Map.OUTHASH1)
				$buffer.CopyTo($outHash, 8)
				$buffer = [BitConverter]::GetBytes($Map.OUTHASH2)
				$buffer.CopyTo($outHash, 12)

				[byte[]]$outHashBase = @(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
				$hashValue1 = ((Get-Long -Bytes $outHash -Index 8) -bxor (Get-Long -Bytes $outHash))
				$hashValue2 = ((Get-Long -Bytes $outHash 12) -bxor (Get-Long -Bytes $outHash -Index 4))

				$buffer = [BitConverter]::GetBytes($hashValue1)
				$buffer.CopyTo($outHashBase, 0)
				$buffer = [BitConverter]::GetBytes($hashValue2)
				$buffer.CopyTo($outHashBase, 4)
				$base64Hash = [Convert]::ToBase64String($outHashBase)
			}

			return $base64Hash
		}

		# Get current user SID
		$userSid = (Get-CimInstance -ClassName Win32_UserAccount | Where-Object -FilterScript {$_.Name -eq $env:USERNAME}).SID
		# Secret static string from %SystemRoot%\SysWOW64\shell32.dll
		$userExperience = "User Choice set via Windows User Experience {D18B6DD5-6124-4341-9318-804003BAFA0B}"
		$userDateTime = Get-HexDateTime
		$baseInfo = "$Extension$userSid$ProgId$userDateTime$userExperience".ToLower()
		$ProgHash = Get-Hash -BaseInfo $baseInfo

		#Handle Extension
		Write-ExtensionKeys -ProgId $ProgId -Extension $Extension -ProgHash $ProgHash

		if ($Icon)
		{
			Set-Icon -ProgId $ProgId -Icon $Icon
		}
	}

	Set-FTA -ProgId $ProgId -Extension $Extension -Icon $Icon
}

cls

Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .cfg -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .ini -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .js -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .json -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .log -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .nfo -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .ps1 -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .psd1 -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .psm1 -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .txt -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .xml -Icon "C:\Program Files\Notepad++\notepad++.exe,0"
Set-Association -ProgramPath "C:\Program Files\Notepad++\notepad++.exe" -Extension .psm1 -Icon "C:\Program Files\Notepad++\notepad++.exe,0"

$UpdateExplorer = @{
	Namespace = "WinAPI"
	Name = "UpdateExplorer"
	Language = "CSharp"
	MemberDefinition = @"
private static readonly IntPtr HWND_BROADCAST = new IntPtr(0xffff);
private const int WM_SETTINGCHANGE = 0x1a;
private const int SMTO_ABORTIFHUNG = 0x0002;

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
static extern bool SendNotifyMessage(IntPtr hWnd, uint Msg, IntPtr wParam, string lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
private static extern IntPtr SendMessageTimeout(IntPtr hWnd, int Msg, IntPtr wParam, string lParam, int fuFlags, int uTimeout, IntPtr lpdwResult);
[DllImport("shell32.dll", CharSet = CharSet.Auto, SetLastError = false)]
private static extern int SHChangeNotify(int eventId, int flags, IntPtr item1, IntPtr item2);
public static void Refresh()
{
	// Update desktop icons
	SHChangeNotify(0x8000000, 0x1000, IntPtr.Zero, IntPtr.Zero);

	// Update environment variables
	SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, IntPtr.Zero, null, SMTO_ABORTIFHUNG, 100, IntPtr.Zero);

	// Update taskbar
	SendNotifyMessage(HWND_BROADCAST, WM_SETTINGCHANGE, IntPtr.Zero, "TraySettings");
}
"@
}
if (-not ("WinAPI.UpdateExplorer" -as [type]))
{
	Add-Type @UpdateExplorer
}

# Refresh desktop icons, environment variables, taskbar
[WinAPI.UpdateExplorer]::Refresh()