PowerShell - List all computers & which users are administrators - powershell

Question

I am trying to create a powershell script that:
Finds all computers in the domain
Queries each computer to determine what groups/users are in the Administrators group
Lists each user/group/computer
The columns should be: Username, GroupName, ComputerName, DomainName
Here's where I am at so far, but I'm looking for some help parsing the WMI results in a consistent fashion, or per
Here's the script so far:
$auditdir = "c:\temp\"
$tempfile = $auditdir + "computers.csv"
$computers = (Get-ADComputer -Filter *)
$Table = #()
$Record = #{
"MachineName" = ""
"GroupName" = ""
"DomainName" = ""
"Username" = ""
}
Foreach ($computername in $computers){
$computername = $computername.name
$ADMINS = get-wmiobject -computername $computername -query "select * from win32_groupuser where GroupComponent=""Win32_Group.Domain='$computername',Name='administrators'""" | % {$_.partcomponent}
foreach ($ADMIN in $ADMINS){
Write-Host "Output current admin"
$admin
Write-Host "Clean up current admin"
$admin = ($admin | Out-String)
$admin = $admin -replace 'cimv2', '' -replace 'Win32','' -replace 'useraccount','' -replace 'root','' -replace $computername,'' -replace ',','' -replace "`n|`r" -replace $env:userdomain,'' -replace 'name','' -replace '=','' -replace ':','' -replace '_','' -replace '\\','' -replace '_','' -replace 'group','' -replace '""',''
$admin.substring(8)
$admin
$admin = $admin | %{$_.split('"')[3]}
$admin
Write-Host "done with current admin"
$Record."Machinename" = $computername
$Record."Groupname" = $admin
$Record."DomainName" = $env:USERDNSDOMAIN
$Record."UserName" = $admin.split("")[1]
$objRecord = New-Object PSObject -property $Record
$Table += $objrecord
}
$Table | Export-Csv $tempfile -NoTypeInformation
}
Can someone please help me get to the finish line?
Update 1:
With Mathias's help, I've cast the results of the WMI query to a WMI type and can access items easier.
$auditdir = "c:\temp\"
$tempfile = $auditdir + "computers.csv"
$computers = (Get-ADComputer -Filter *)
$Table = #()
$Record = #{
"ComputerName" = ""
"MemberName" = ""
"DomainName" = ""
"SID" = ""
}
Foreach ($computername in $computers){
$computername = $computername.name
$ADMINS = get-wmiobject -computername $computername -query "select * from win32_groupuser where GroupComponent=""Win32_Group.Domain='$computername',Name='administrators'""" | % {$_.partcomponent}
foreach ($ADMIN in $ADMINS){
$admin = [WMI]$admin
$admin
$Record."ComputerName" = $computername
$Record."MemberName" = $admin.name
$Record."DomainName" = $env:USERDNSDOMAIN
$Record."SID" = $admin.SID
$objRecord = New-Object PSObject -property $Record
$Table += $objrecord
}
$Table | Export-Csv $tempfile -NoTypeInformation
}
I seem to be running into an issue with domain admins group. It can't seem to be converted to WMI and then parsed.
Error is:
Cannot convert value "\\computername\root\cimv2:Win32_Group.Domain="domain",Name="Domain Admins"" to type
"System.Management.ManagementObject". Error: "Not found "
At C:\Users\f12admin\Desktop\computerlist.ps1:20 char:3
+ $admin = [WMI]$admin
+ ~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvalidCastToWMI