Script PC Inventory with PowerShell

$Log = "$results.txt"
$HostListFile = "hosts.txt"
Remove-Item -Force $Log -ErrorAction Ignore
Remove-Variable Hostname -ErrorAction Ignore
Remove-Variable Target -ErrorAction Ignore
Remove-Variable pcinfo -ErrorAction Ignore

$Hostname = $args[0]
if (!$Hostname) {
	$Hostname = Read-Host -Prompt "Enter Hostname [$Hostname] "
}
if (!$Hostname) {
	$Target = "self"
	$Hostname = $env:computername
}
if ($Hostname -eq "file"){
	[string[]]$Hostname = Get-Content -Path $HostListFile
	$Target = "file"
}
if ($Target -ne "file") {
	$Hostname = $Hostname.Split(",")
}

function SuperPing($Hostname) {
	Remove-Variable reply -ErrorAction Ignore 
	[int]$timeout = 20
	[switch]$resolve = $true
	[int]$TTL = 128
	[switch]$DontFragment = $false
	[int]$buffersize = 32
	$options = new-object system.net.networkinformation.pingoptions
	$options.TTL = $TTL
	$options.DontFragment = $DontFragment
	$buffer=([system.text.encoding]::ASCII).getbytes("a"*$buffersize)	
	$ping = new-object system.net.networkinformation.ping
	$reply = $ping.Send($Hostname,$timeout,$buffer,$options)
		if ($reply.Status -eq "Success"){
			return "True"
		}
		else {
			return "False"
		}
}
function Get-Inventory() {
	function Get-Mac () {
		$network = (Get-WmiObject win32_networkadapterconfiguration | where{$_.DHCPEnabled -eq "True"} | where{$_.MacAddress -notlike ""} | where{$_.Description -notlike "*Virtual*"} | where{$_.Description -notlike "*Bluetooth*"})
		$mac = ""
		foreach ($mac_item in $network) {
			$mac += $mac_item.MacAddress
		}
		return $mac
	}
	function Get-Encryption() {
		$bitlocker = Get-BitlockerVolume -MountPoint C
		if ($bitlocker.ProtectionStatus -eq 'off') {
			return "No"
		} else {
			return "Yes"
		}
	}
	function Get-Installed($program) {
	$sw1 = gp HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*
	$sw2 = gp HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*
		if ((($sw1).DisplayName -Match $program).Length -gt 0 -eq "True" -Or `
			(($sw2).DisplayName -Match $program).Length -gt 0 -eq "True") {
			return "Yes"
		}
		else {
			return "No"
		}

	}
	function Get-Type($model) {
		if ($model -Like "*XPS 15*" -Or $model -Like "*XPS 13*" -Or $model -Like "*Latitude*"){
			return "Laptop"
		}
		elseif ($model -Like "*Optiplex*") {
			return "Desktop"
		}
		else {
			return "Unknown"
		}
	}
	function Get-Dell([string]$ServiceTag) {
	$ApiKey="REPLACE_WITH_DELL_API_KEY"
	$KeySecret="REPLACE_WITH_DELL_KEY_SECRET"
		if (!$token) {
			$AuthURI = "https://apigtwb2c.us.dell.com/auth/oauth/v2/token"
			$OAuth = "$ApiKey`:$KeySecret"
			$Bytes = [System.Text.Encoding]::ASCII.GetBytes($OAuth)
			$EncodedOAuth = [Convert]::ToBase64String($Bytes)
			$Headers = @{ }
			$Headers.Add("authorization", "Basic $EncodedOAuth")
			$Authbody = 'grant_type=client_credentials'
			[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
			$AuthResult = Invoke-RESTMethod -Method Post -Uri $AuthURI -Body $AuthBody -Headers $Headers
			$token = $AuthResult.access_token
			$headers = @{"Accept" = "application/json" }
			$headers.Add("Authorization", "Bearer $token")
		}
	$params = @{ }
	$params = @{servicetags = $ServiceTag; Method = "GET" }
	$response = Invoke-RestMethod -Uri "https://apigtwb2c.us.dell.com/PROD/sbil/eapi/v5/asset-entitlements" -Headers $headers -Body $params -Method Get -ContentType "application/json" -ea 0
	$Json = $response | ConvertTo-Json
	$response = $Json | ConvertFrom-Json 
	$Device = $response.productLineDescription
	$ShipDate = $response.shipDate
	$EndDate = ($response.entitlements | Select -Last 1).endDate
	$ShipDate = $ShipDate | Get-Date -f "MM-dd-y"
	$EndDate = $EndDate | Get-Date -f "MM-dd-y"
	$type = $response.ProductID
	if ($type -Like '*desktop*') { 
		$type = 'desktop'        
	}
	elseif ($type -Like '*laptop*') { 
		$type = 'laptop'
	}
	return $ShipDate, $EndDate, $type
	}

	$pcinfo = New-Object -TypeName psobject
	$system_info = Get-CimInstance -ClassName Win32_ComputerSystem
	$serial = (gwmi win32_bios).SerialNumber
	$model = $system_info.Manufacturer + " " + $system_info.Model
	$mac = Get-Mac
	$encryption = Get-Encryption
	$software1 = Get-Installed("Software1")
	$Software2 = Get-Installed("software2")
	if ($model -like "*Dell*"){
		$dell = Get-Dell($serial)
	}
	if (!$dell[2]) {
		$type = Get-Type($model)
	}
	else {
		$type = $dell[2]
	}

	$pcinfo | Add-Member -NotePropertyName Name -NotePropertyValue $system_info.Name
	$pcinfo | Add-Member -NotePropertyName Domain -NotePropertyValue $system_info.Domain
	$pcinfo | Add-Member -NotePropertyName Serial -NotePropertyValue $serial
	$pcinfo | Add-Member -NotePropertyName OS -NotePropertyValue (Get-WmiObject -Class Win32_OperatingSystem).Caption
	$pcinfo | Add-Member -NotePropertyName Model -NotePropertyValue $model
	$pcinfo | Add-Member -NotePropertyName Memory -NotePropertyValue ([string]($system_info.TotalPhysicalMemory/1GB -as [int]) + "GB")
	$pcinfo | Add-Member -NotePropertyName Mac -NotePropertyValue $mac
	$pcinfo | Add-Member -NotePropertyName Encryption -NotePropertyValue $encryption
	$pcinfo | Add-Member -NotePropertyName Type -NotePropertyValue $type
	$pcinfo | Add-Member -NotePropertyName Software1 -NotePropertyValue $software1
	$pcinfo | Add-Member -NotePropertyName Software2 -NotePropertyValue $software2
	$pcinfo | Add-Member -NotePropertyName "Ship Date" -NotePropertyValue $dell[0]
	$pcinfo | Add-Member -NotePropertyName "Exp. Date" -NotePropertyValue $dell[1]

	return $pcinfo
}
function Get-Output($pcinfo) {
	$pcinfo `
	| Select-Object Name, Domain, Serial, OS, Model, Memory, Mac, Encryption, `
	Type, Software1, Software2, "Ship Date", "Exp. Date" `
	| Format-List | Out-String | Write-Host
	echo $null | clip.exe
	Remove-Variable clippy -ErrorAction Ignore
	$tab = [char]9
	$clippy = `
	$pcinfo.Name+$tab+`
	$pcinfo.Model+$tab+`
	$pcinfo.Serial+$tab+`
	$pcinfo.Type+$tab+`
	$pcinfo.Memory+$tab+`
	$pcinfo.Mac+$tab+`
	$pcinfo.OS+$tab+`
	$pcinfo.Software1+$tab+`
	$pcinfo.Software2+$tab+`
	$pcinfo.Domain+$tab+`
	$pcinfo.Encryption+$tab+`
	$pcinfo.'Ship Date'+$tab+`
	$pcinfo.'Exp. Date'+$tab
	Set-Clipboard $clippy
	Write-Output $clippy >> $Log
}
if ($Target -eq "self") {
	$pcinfo = Get-Inventory
	Get-Output($pcinfo)
}
else {
	foreach ($thing in $Hostname) {
		$online = SuperPing($thing)
		if ($online -eq "False") {
			Write-Host "$thing is unreachable"
			Write-Output "$thing is unreachable" >> $Log
		}
		else {
			Remove-Variable pcinfo -ErrorAction Ignore
			$pcinfo = Invoke-Command -ComputerName $thing -ScriptBlock ${Function:Get-Inventory}
			Get-Output($pcinfo)
		}
	}
}