#Requires -version 3
<#
.Synopsis
Find the distinguishedName of AD User, Computer, and Group objects. 

.DESCRIPTION
This script gets the DistinguishedName of User, Computer, and Group Objects
by searching the forest.  It does not depend on the ActiveDirectory Module

.PARAMETER ADObject
Required input object. Computer or group name, User SamAccountName

.PARAMETER ADObjectType 
Required input object, select from User, Computer or Group

.NOTES
12/24/21 public version
Alan Kaplan, www.akaplan.com

.EXAMPLE
.\Find-ADObject.ps1 $env:USERNAME -ObjectType User
Find the DistinguishedName of current user

.EXAMPLE
.\Find-ADObject.ps1 -adobject 'MyGroup' -ADObjectType Group
Find the DistinguishedName of MyGroup
#>

[CmdletBinding()]
Param
(
    # ADObject: Computer or group name, User SamAccountName  
    [Parameter(Mandatory = $true, Position = 0)]
    $adobject,

    # ADObjectType - User, group or description
    [Parameter(Mandatory = $true, 
        ValueFromPipeline = $true,
        ValueFromPipelineByPropertyName = $true, 
        ValueFromRemainingArguments = $false, 
        Position = 1,
        ParameterSetName = 'PS1')]
    [ValidateNotNull()]
    [ValidateNotNullOrEmpty()]
    [ValidateSet("User", "Computer", "Group")]

    $ADObjectType
)

$searchRoot = [system.directoryservices.activedirectory.forest]::GetCurrentForest().Name.ToString()
$SearchPath = "GC://" + $SearchRoot
$de = New-Object System.DirectoryServices.DirectoryEntry($SearchPath)
$ds = New-Object System.DirectoryServices.DirectorySearcher
$ds.SearchRoot = $de

switch ($PSBoundParameters.item('ADObjectType')) {
    'Computer' {
        $ds.Filter = "(&(objectCategory=computer)(objectClass=computer)(Name=$adobject))"
        Break
    }
    'User' {          
        $ds.Filter = "(&(objectCategory=Person)(objectClass=User)(|(SamAccountName=$adobject)(userprincipalname=$adobject)))"
        Break
    }
    'Group' {
        #Include dynamic distribution 
        $ds.filter = "(&(|(Name=$adobject)(cn=$adObject)(SamAccountName=$adObject))(|(objectClass=Group)(objectClass=msExchDynamicDistributionList)))"
    }
}

$ds.SearchScope = "SubTree"
$retval = $ds.FindAll()

if ($retval.count -gt 0) {
    if ($retval.count -gt 1) { Write-Host "$($retval.count) found." -ForegroundColor Green }
    $Retval | ForEach-Object { 
        [PSCustomObject]@{
            DistinguishedName = $_.Properties.distinguishedname[0]
        }
    } 
}
ELSE {
    Write-Warning "$adobject Not Found"
}