GPOZaurr/Public/Get-GPOZaurrLink.ps1

function Get-GPOZaurrLink {
    [cmdletbinding(DefaultParameterSetName = 'Linked')]
    param(
        [parameter(ParameterSetName = 'ADObject', ValueFromPipeline, ValueFromPipelineByPropertyName, Mandatory)][Microsoft.ActiveDirectory.Management.ADObject[]] $ADObject,
        # site doesn't really work this way unless you give it 'CN=Configuration,DC=ad,DC=evotec,DC=xyz' as SearchBase
        [parameter(ParameterSetName = 'Filter')][string] $Filter, # "(objectClass -eq 'organizationalUnit' -or objectClass -eq 'domainDNS' -or objectClass -eq 'site')"
        [parameter(ParameterSetName = 'Filter')][string] $SearchBase,
        [parameter(ParameterSetName = 'Filter')][Microsoft.ActiveDirectory.Management.ADSearchScope] $SearchScope,

        [parameter(ParameterSetName = 'Linked')][validateset('All', 'Root', 'DomainControllers', 'Site', 'OrganizationalUnit')][string[]] $Linked,

        [parameter(ParameterSetName = 'Site')][string[]] $Site,

        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [switch] $Limited,

        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [switch] $SkipDuplicates,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [System.Collections.IDictionary] $GPOCache,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [alias('ForestName')][string] $Forest,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [string[]] $ExcludeDomains,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [alias('Domain', 'Domains')][string[]] $IncludeDomains,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [System.Collections.IDictionary] $ExtendedForestInformation,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [switch] $AsHashTable,

        [parameter(ParameterSetName = 'Site')]
        [parameter(ParameterSetName = 'Filter')]
        [parameter(ParameterSetName = 'ADObject')]
        [parameter(ParameterSetName = 'Linked')]
        [switch] $Summary
    )
    Begin {
        $CacheReturnedGPOs = [ordered] @{}
        $ForestInformation = Get-WinADForestDetails -Extended -Forest $Forest -IncludeDomains $IncludeDomains -ExcludeDomains $ExcludeDomains -ExtendedForestInformation $ExtendedForestInformation
        if (-not $GPOCache -and -not $Limited) {
            $GPOCache = @{ }
            # While initially we used $ForestInformation.Domains but the thing is GPOs can be linked to other domains so we need to get them all so we can use cache of it later on even if we're processing just one domain
            # That's why we use $ForestInformation.Forest.Domains instead
            foreach ($Domain in $ForestInformation.Forest.Domains) {
                Write-Verbose "Get-GPOZaurrLink - Building GPO cache for domain $Domain"
                if ($ForestInformation['QueryServers'][$Domain]) {
                    $QueryServer = $ForestInformation['QueryServers'][$Domain]['HostName'][0]
                    Get-GPO -All -DomainName $Domain -Server $QueryServer | ForEach-Object {
                        $GPOCache["$Domain$($_.ID.Guid)"] = $_
                    }
                } else {
                    Write-Warning -Message "Get-GPOZaurrLink - Couldn't get query server for $Domain. Skipped."
                }
            }
        }
    }
    Process {
        $getGPOLoopSplat = @{
            Linked            = $Linked
            ForestInformation = $ForestInformation
            SearchScope       = $SearchScope
            SearchBase        = $SearchBase
            ADObject          = $ADObject
            Filter            = $Filter
            SkipDuplicates    = $SkipDuplicates
            Site              = $Site
        }
        Remove-EmptyValue -Hashtable $getGPOLoopSplat -Recursive
        $getGPOLoopSplat['CacheReturnedGPOs'] = $CacheReturnedGPOs
        if ($AsHashTable -or $Summary) {
            $HashTable = [ordered] @{}
            $SummaryHashtable = [ordered] @{}
            $Links = Get-GPOZaurrLinkLoop @getGPOLoopSplat
            foreach ($Link in $Links) {
                $Key = -join ($Link.DomainName, $Link.GUID)
                if (-not $HashTable[$Key]) {
                    $HashTable[$Key] = [System.Collections.Generic.List[PSCustomObject]]::new()
                }
                $HashTable[$Key].Add($Link)
            }
            foreach ($Key in $HashTable.Keys) {
                [Array] $Link = $HashTable[$Key]
                $EnabledLinks = $Link.Enabled.Where( { $_ -eq $true }, 'split')

                $LinkedRoot = $false
                $LinkedRootPlaces = [System.Collections.Generic.List[string]]::new()
                $LinkedSite = $false
                $LinkedSitePlaces = [System.Collections.Generic.List[string]]::new()
                $LinkedOU = $false
                $LinkedCrossDomain = $false
                $LinkedCrossDomainPlaces = [System.Collections.Generic.List[string]]::new()
                foreach ($InternalLink in $Link) {
                    if ($InternalLink.ObjectClass -eq 'domainDNS') {
                        $LinkedRoot = $true
                        $LinkedRootPlaces.Add($InternalLink.DistinguishedName)
                    } elseif ($InternalLink.ObjectClass -eq 'site') {
                        $LinkedSite = $true
                        $LinkedSitePlaces.Add($InternalLink.Name)
                    } else {
                        $LinkedOU = $true
                    }
                    $CN = ConvertFrom-DistinguishedName -ToDomainCN -DistinguishedName $InternalLink.distinguishedName
                    $GPOCN = ConvertFrom-DistinguishedName -ToDomainCN -DistinguishedName $InternalLink.GPODomainDistinguishedName
                    if ($CN -ne $GPOCN) {
                        $LinkedCrossDomain = $true
                        $LinkedCrossDomainPlaces.Add($InternalLink.DistinguishedName)
                    }
                }
                if ($EnabledLinks[0].Count -gt 0) {
                    $IsLinked = $true
                } else {
                    $IsLinked = $false
                }
                $SummaryLink = [PSCustomObject] @{
                    DisplayName             = $Link[0].DisplayName
                    DomainName              = $Link[0].DomainName
                    GUID                    = $Link[0].GUID
                    Linked                  = $IsLinked
                    LinksCount              = $Link.Count
                    LinksEnabledCount       = $EnabledLinks[0].Count
                    LinksDisabledCount      = $EnabledLinks[1].Count
                    LinkedCrossDomain       = $LinkedCrossDomain
                    LinkedRoot              = $LinkedRoot
                    LinkedSite              = $LinkedSite
                    LinkedOU                = $LinkedOU
                    LinkedSitePlaces        = $LinkedSitePlaces
                    LinkedRootPlaces        = $LinkedRootPlaces
                    LinkedCrossDomainPlaces = $LinkedCrossDomainPlaces
                    Links                   = $Link.DistinguishedName
                    LinksObjects            = $Link
                }
                $SummaryHashtable[$Key] = $SummaryLink
            }
            if ($AsHashTable -and $Summary) {
                $SummaryHashtable
            } elseif ($AsHashTable) {
                $HashTable
            } elseif ($Summary) {
                $SummaryHashtable.Values
            }
        } else {
            Get-GPOZaurrLinkLoop @getGPOLoopSplat
        }
    }
    End {

    }
}