#MAK & ESU discovery v3

$Esu1Bool = $false
$Esu2Bool = $false
$Esu3Bool = $false
$MakBool = $false

$OS = (Get-WmiObject Win32_OperatingSystem).Caption
Write-Verbose $OS

$Esu1Key = '4RPR3-NRF26-9CTKB-7GRXQ-GF72Q'
$Esu2Key = $null
$Esu3Key = $null

# activation IDs found here
# https://techcommunity.microsoft.com/t5/windows-it-pro-blog/windows-server-2012-r2-extended-security-updates/ba-p/3976610
$Esu1Id = 'c0a2ea62-12ad-435b-ab4f-c9bfab48dbc4'
$Esu2Id = 'e3e2690b-931c-4c80-b1ff-dffba8a81988'
$Esu3Id = '55b1dd2d-2209-4ea0-a805-06298bad25b3'

$software = Get-WmiObject -Class SoftwareLicensingProduct

If ($Esu1Key) {
    Write-Verbose -Message "Esu1Key found, checking LicenseStatus"
    $EsuYear1 = $software | Where-Object { $_.Id -eq $Esu1Id }
    If ($EsuYear1) {
        If ($EsuYear1.LicenseStatus -eq '1') {
            $Esu1Bool = $true
        }
    }
}

If ($Esu2Key) {
    Write-Verbose -Message "Esu2Key found, checking LicenseStatus"
    $EsuYear2 = $software | Where-Object { $_.Id -eq $Esu2Id }
    If ($EsuYear2) {
        If ($EsuYear2.LicenseStatus -eq '1') {
            $Esu2Bool = $true
        }
    }
}

If ($Esu3Key) {
    Write-Verbose -Message "Esu3Key found, checking LicenseStatus"
    $EsuYear3 = $software | Where-Object { $_.Id -eq $Esu3Id }
    If ($EsuYear3) {
        If ($EsuYear3.LicenseStatus -eq '1') {
            $Esu3Bool = $true
        }
    }
}

# Year 1 only
If ($Esu1Key -and $null -eq $Esu2Key -and $null -eq $Esu3Key) {
    If ($Esu1Bool -eq $true) {
        $compliant = $true
    }
    else {
        $compliant = $false
    }
}

# Year 1 & 2
If ($Esu1Key -and $Esu2Key -and $null -eq $Esu3Key) {
    If ($Esu1Bool -eq $true -and $Esu2Bool -eq $true) {
        $compliant = $true
    }
    else {
        $compliant = $false
    }
}

# Year 1 & 2 & 3
If ($Esu1Key -and $Esu2Key -and $Esu3Key ) {
    If ($Esu1Bool -eq $true -and $Esu2Bool -eq $true -and $Esu3Bool -eq $true) {
        $compliant = $true
    }
    else {
        $compliant = $false
    }
}

$compliant