#requires -version 2
param (
[string] $class = $(throw "The WMI Class is required."),
[array] $attributes,
[string] $NameSpace
)
$erroractionpreference = "SilentlyContinue"
$thisScript = Split-Path $myInvocation.MyCommand.Path -Leaf
$scriptRoot = Split-Path(Resolve-Path $myInvocation.MyCommand.Path)
$OutPutCSVFile = Join-Path $scriptRoot "WMIInventory.csv"

#Default WMI Name Space is "Root\CIMV2"
if ($NameSpace -eq $null) {$NameSpace = "Root\CIMV2"}

function CheckComputerConnectivity($computer)
{
	$result = $false
	#check if the computer can be pinged.
	"checking $computer"
	$ping = New-Object Net.NetworkInformation.Ping
	$PingResult = $ping.send($computer)
	if ($PingResult.Status.Tostring().ToLower() -eq "success")
	{
		$result = $true					
	} else {
		Write-Host "$computer cannot be reached"
	}
	return $result
}

function GetServersFromOU([string]$strDomainName, [array]$arrOUs, [array]$arrExcludedOus)
{
	$arrDCs = $strDomainName.split(".")
	$strFullDC = $null
	foreach ($DC in $arrDCs)
	{
		if ($strFullDC -eq $null)
		{
			$strFullDC = "DC=$DC"
		}
		else
		{
			$strFullDC = "$strFullDC,DC=$DC"
		}
	}
	#Get the Distingushed Names for Excluded OUs
	if ($arrExcludedOus -ne $null)
	{
		for ($i=0; $i -le ($arrExcludedOus.count-1); $i++)
		{
			$arrExcludedOus[$i] = $arrExcludedOus[$i] + ",$strFullDC"
		}
		
	}

	$arrComputers = @( )
	foreach ($Ou in $arrOUs)
	{
		$strFilter = "computer"
										
		$objDomain = New-Object System.DirectoryServices.DirectoryEntry
										
		$objSearcher = New-Object System.DirectoryServices.DirectorySearcher
		$objSearcher.SearchRoot = "LDAP://$OU,$strFullDC"
		$objSearcher.SearchScope = "subtree" 
		$objSearcher.PageSize = 3000
										
		$objSearcher.Filter = "(objectCategory=$strFilter)"
		$colResults = $objSearcher.FindAll()
					
						
		foreach ($item in $colResults)
		{
			$objComputer = $item.GetDirectoryEntry()
			#Only add the computer to the array if it is not in the excluded OUs.
			$bCorrectOU = $true
			foreach ($Ou in $arrExcludedOus)
			{
				if ($objComputer.distinguishedName.tostring() -match $Ou)
				{
					$bCorrectOU = $false
					#Write-Host "$bCorrectOU, $objComputer.distinguishedName.tostring()"
				}
			}
			if ($bCorrectOU -eq $true)
			{
				$arrComputers += $objComputer.Name
			}
		}
	}
		$arrcomputers = $arrcomputers | Sort-Object
	return $arrComputers
}

$strDomain = "<Domain>"
$arrOUs = @( )
$ExcludedOus = @()
#adding OUs
$arrOus += "OU=<OU1>"
$arrOus += "OU=<OU2>,OU=<OU3>"
#Adding excluded OUs
$ExcludedOus += "OU=<OU4>,OU=<OU1>"
$ExcludedOus += "OU=<OU5>,OU=<OU1>"

#Get computers
$arrComputers = GetServersFromOU $strDomain $arrOUs $ExcludedOus


$arrWMI = @()

#if no desired attributes is passed in, use 'select *' when querying WMI class.
if ($attributes.count -eq 0 -or $attributes -eq $null)
{
	$attributes += "*"
}
	$strQuery = "Select"
	Foreach ($attribute in $attributes)
	{
		$strQuery = $strQuery + " $attribute,"
	}
	$strQuery = $strQuery.substring(0, ($strQuery.length-1))
	$strQuery = "$strQuery from $class"
Write-Host $strQuery

foreach ($computer in $arrComputers)
{
		#Check connectivities
		$IsComputerAccessible = CheckComputerConnectivity $computer
		if ($IsComputerAccessible -eq $true)
		{
			#Get-WmiObject cannot be used because cannot set timeout for WMI queries
			Write-Host "Checking $computer..."
			$wmi = [WMISearcher]''
			$wmi.options.timeout = '0:0:30'	#set timeout to 30 seconds
			$wmi.scope.path = "\\$Computer\$NameSpace"
			$wmi.query = $strQuery
			$ColObjWMI = $wmi.get()
			
			#a collection is returned from above command
			Foreach ($obj in $ColObjWMI)
			{
				#Create a custom psobject to only store the properties we need (including the computer name and WMI Class)
				$psobjWMI = $null
				$psobjWMI= New-Object psobject
				Add-Member -InputObject $psobjWMI -membertype noteproperty -name ComputerName -value $computer
				Add-Member -InputObject $psobjWMI -membertype noteproperty -name WMIClass -value $class
				
				#Looping through each property and add to the custom psobject
				Foreach ($property in ($Obj| Get-Member -MemberType Property))
				{
					$strProperty = $property.Name
					if ($strProperty.substring(0,1) -ne "_")
					{
						$strValue = $obj.$strProperty
						Add-Member -InputObject $psobjWMI -membertype noteproperty -name $strProperty -value $strValue
					}	
				}
				#Adding the custom psobject to an array
				$arrWMI += $psobjWMI
			}
			
		} else {
			$strError = "$Computer cannot be reached."
		}
}

#Export the output array to CSV
$arrWMI | Select-Object -Property * -ExcludeProperty "_*"| Sort-Object | Export-Csv -notypeinformation $OutPutCSVFile -Force