GPOZaurr/Public/Get-GPOZaurrLinkSummary.ps1

function Get-GPOZaurrLinkSummary {
    <#
    .SYNOPSIS
    Retrieves a summary of GPO links based on specified criteria.

    .DESCRIPTION
    This function retrieves a summary of GPO links based on the provided parameters. It categorizes the links into different types and provides detailed information about each link.

    .PARAMETER Report
    Specifies the type of report to generate. Valid values are 'All', 'MultipleLinks', 'OneLink', and 'LinksSummary'. Default is 'All'.

    .PARAMETER UnlimitedProperties
    Indicates whether to include unlimited properties in the report.

    .PARAMETER Forest
    Specifies the forest name to retrieve GPO links from.

    .PARAMETER ExcludeDomains
    Specifies an array of domains to exclude from the report.

    .PARAMETER IncludeDomains
    Specifies an array of domains to include in the report.

    .PARAMETER ExtendedForestInformation
    Specifies additional information about the forest.

    .EXAMPLE
    Get-GPOZaurrLinkSummary -Forest "Contoso" -IncludeDomains "Domain1", "Domain2" -Report "MultipleLinks"
    Retrieves a summary of GPO links for the specified forest and included domains, focusing on multiple links.

    .EXAMPLE
    Get-GPOZaurrLinkSummary -Forest "Fabrikam" -ExcludeDomains "Domain3" -Report "OneLink"
    Retrieves a summary of GPO links for the specified forest excluding Domain3, focusing on a single link.

    #>
    [cmdletBinding()]
    param(
        [ValidateSet('All', 'MultipleLinks', 'OneLink', 'LinksSummary')][string[]] $Report = 'All',
        [switch] $UnlimitedProperties,

        [alias('ForestName')][string] $Forest,
        [string[]] $ExcludeDomains,
        [alias('Domain', 'Domains')][string[]] $IncludeDomains,
        [System.Collections.IDictionary] $ExtendedForestInformation
    )
    $HighestCount = 0 # to keep number of depth
    $CacheSummaryLinks = [ordered] @{} # cache

    # Get all links
    $Links = Get-GPOZaurrLink -Forest $Forest -IncludeDomains $IncludeDomains -ExcludeDomains $ExcludeDomains -ExtendedForestInformation $ExtendedForestInformation -Linked Root, DomainControllers, OrganizationalUnit
    foreach ($Link in $Links) {
        if (-not $CacheSummaryLinks["$($Link.DomainName)$($Link.Guid)"]) {
            $CacheSummaryLinks["$($Link.DomainName)$($Link.Guid)"] = [System.Collections.Generic.List[System.Object]]::new()
        }
        $CacheSummaryLinks["$($Link.DomainName)$($Link.Guid)"].Add($Link)
    }

    $ReturnObject = [ordered] @{
        MultipleLinks = [System.Collections.Generic.List[System.Object]]::new()
        OneLink       = [System.Collections.Generic.List[System.Object]]::new()
        LinksSummary  = [System.Collections.Generic.List[System.Object]]::new()
    }

    foreach ($Key in $CacheSummaryLinks.Keys) {
        $GPOs = $CacheSummaryLinks[$Key]

        [Array] $LinkingSummary = foreach ($GPO in $GPOs) {
            $SplitttedOU = ($GPO.DistinguishedName -split ',')
            [Array] $Clean = foreach ($_ in $SplitttedOU) {
                if ($_ -notlike 'DC=*') { $_ -replace 'OU=' }
            }
            if ($Clean.Count -gt $HighestCount) {
                $HighestCount = $Clean.Count
            }
            if ($Clean) {
                $Test = [ordered] @{
                    DisplayName = $GPO.DisplayName
                    Guid        = $GPO.Guid
                    DomainName  = $GPO.DomainName
                    Level0      = ConvertFrom-DistinguishedName -DistinguishedName $GPO.DistinguishedName -ToDomainCN
                }
                for ($i = 1; $i -le 10; $i++) {
                    $Test["Level$i"] = $Clean[ - $i]
                }
                [PSCustomobject] $Test
            } else {
                $Test = [ordered] @{
                    DisplayName = $GPO.DisplayName
                    Guid        = $GPO.Guid
                    DomainName  = $GPO.DomainName
                    Level0      = $GPO.CanonicalName
                }
                for ($i = 1; $i -le 10; $i++) {
                    $Test["Level$i"] = $null
                }
                [PSCustomobject] $Test
            }
        }
        if ($Report -contains 'MultipleLinks' -or $Report -contains 'All') {
            foreach ($Link in $LinkingSummary) {
                $ReturnObject.MultipleLinks.Add($Link)
            }
            #continue
        }
        if ($Report -eq 'OneLink' -or $Report -contains 'All') {
            $List = [ordered] @{
                DisplayName = $GPOs[0].DisplayName
                Guid        = $GPOs[0].Guid
                DomainName  = $GPOs[0].DomainName
                LinksCount  = $GPOs.Count
            }
            for ($i = 0; $i -le 10; $i++) {
                $List["Level$i"] = ($LinkingSummary."Level$i" | Select-Object -Unique).Count
                $List["Level$($i)List"] = ($LinkingSummary."Level$i" | Select-Object -Unique)
            }
            $List.LinksDistinguishedName = $GPOs.DistinguishedName          # = Computers, OU = ITR02, DC = ad, DC = evotec, DC = xyz
            $List.LinksCanonicalName = $GPOs.CanonicalName

            $List.Owner = $GPOs[0].Owner                      #: EVOTEC\Domain Admins
            $List.GpoStatus = $GPOs[0].GpoStatus                  #: AllSettingsEnabled
            $List.Description = $GPOs[0].Description                #:
            $List.CreationTime = $GPOs[0].CreationTime               #: 16.12.2019 21:25:32
            $List.ModificationTime = $GPOs[0].ModificationTime           #: 30.05.2020 19:12:58
            $List.GPODomainDistinguishedName = $GPOs[0].GPODomainDistinguishedName #: DC = ad, DC = evotec, DC = xyz
            $List.GPODistinguishedName = $GPOs[0].GPODistinguishedName       #: cn = { AA782787 - 002B-4B8C-886F-05873F2DC0CA }, cn = policies, cn = system, DC = ad, DC = evotec, DC = xy

            $ReturnObject.OneLink.Add( [PSCustomObject] $List)
        }
        if ($Report -eq 'LinksSummary' -or $Report -contains 'All') {
            $Output = [PSCustomObject] @{
                DisplayName                = $GPOs[0].DisplayName                #: COMPUTERS | LAPS
                Guid                       = $GPOs[0].Guid                       #: AA782787 - 002B-4B8C-886F-05873F2DC0CA
                DomainName                 = $GPOs[0].DomainName                 #: ad.evotec.xyz
                LinksCount                 = $GPOs.Count
                LinksDistinguishedName     = $GPOs.DistinguishedName          # = Computers, OU = ITR02, DC = ad, DC = evotec, DC = xyz
                LinksCanonicalName         = $GPOs.CanonicalName              #: ad.evotec.xyz / ITR02 / Computers
                Owner                      = $GPOs[0].Owner                      #: EVOTEC\Domain Admins
                GpoStatus                  = $GPOs[0].GpoStatus                  #: AllSettingsEnabled
                Description                = $GPOs[0].Description                #:
                CreationTime               = $GPOs[0].CreationTime               #: 16.12.2019 21:25:32
                ModificationTime           = $GPOs[0].ModificationTime           #: 30.05.2020 19:12:58
                GPODomainDistinguishedName = $GPOs[0].GPODomainDistinguishedName #: DC = ad, DC = evotec, DC = xyz
                GPODistinguishedName       = $GPOs[0].GPODistinguishedName       #: cn = { AA782787 - 002B-4B8C-886F-05873F2DC0CA }, cn = policies, cn = system, DC = ad, DC = evotec, DC = xy
            }
            $ReturnObject.LinksSummary.Add($Output)
        }
    }
    # Processing output
    if (-not $UnlimitedProperties) {
        if ($Report -contains 'MultipleLinks' -or $Report -contains 'All') {
            $Properties = @(
                'DisplayName'
                'DomainName'
                'GUID'
                for ($i = 0; $i -le $HighestCount; $i++) {
                    "Level$i"
                }
                #'Owner'
                #'GpoStatus'
                #'Description'
                #'CreationTime'
                #'ModificationTime'
                #'GPODomainDistinguishedName'
                #'GPODistinguishedName'
            )
            $ReturnObject.MultipleLinks = $ReturnObject.MultipleLinks | Select-Object -Property $Properties
        }
        if ($Report -contains 'OneLink' -or $Report -contains 'All') {
            $Properties = @(
                'DisplayName'
                'DomainName'
                'GUID'
                for ($i = 0; $i -le $HighestCount; $i++) {
                    "Level$i"
                    "Level$($i)List"
                }
                'LinksDistinguishedName'
                'LinksCanonicalName'
                'Owner'
                'GpoStatus'
                'Description'
                'CreationTime'
                'ModificationTime'
                'GPODomainDistinguishedName'
                'GPODistinguishedName'
            )
            $ReturnObject.OneLink = $ReturnObject.OneLink | Select-Object -Property $Properties
        }
        #if ($Report -contains 'LinksSummary' -or $Report -contains 'All') {
        # Not needed because there's no dynamic properties, but if there would be we need to uncomment and fix it
        #}
    }
    if ($Report.Count -eq 1 -and $Report -notcontains 'All') {
        $ReturnObject["$Report"]
    } else {
        $ReturnObject
    }
}