#Requires -version 2.0

# -----------------------------------------------------------------------------
# Script: Get-GPOBackup.ps1
# Version: 1.4
# Author: Jeffery Hicks
#    http://jdhitsolutions.com/blog
#    http://twitter.com/JeffHicks
# Date: 5/23/2011
# Keywords: GPO, Backup, GroupPolicy, GUID, XML
# Comments:
#
# "Those who forget to script are doomed to repeat their work."
#
#  ****************************************************************
#  * DO NOT USE IN A PRODUCTION ENVIRONMENT UNTIL YOU HAVE TESTED *
#  * THOROUGHLY IN A LAB ENVIRONMENT. USE AT YOUR OWN RISK.  IF   *
#  * YOU DO NOT UNDERSTAND WHAT THIS SCRIPT DOES OR HOW IT WORKS, *
#  * DO NOT USE IT OUTSIDE OF A SECURE, TEST SETTING.             *
#  ****************************************************************
# -----------------------------------------------------------------------------

Function Get-GPOBackup {

<#
.SYNOPSIS
Retrieve GPO Backup information
.DESCRIPTION
This command will search a given path for Group Policy Object backups and write backup information to the pipeline.
The command will write a custom object to the pipeline for each GPO backup like this.

Backup   : 5/2/2011 8:10:13 PM
Name     : WinRM Configuration
BackupID : 5AAFD6DF-24C0-40EF-9DF1-AC9C279E010B
Path     : \\server01\backup\gpo\
Domain   : jdhlab.local
Guid     : 38228a9f-f2ec-4b48-8829-4f3131e4f77c
Comment  : second backup

If you want to only retrieve the most current backup version use the -Latest parameter.

.PARAMETER Path
The top leve folder to search. This can be a drive letter or a UNC. The parameter will default
to the global $GPBackupPath variable.
.PARAMETER Name
The name of a GPO. Wildcards are permitted.
.PARAMETER Latest
If there are multiple backups of the same GPO, return the most recent version.
.EXAMPLE
PS C:\> Get-GPOBackup 
Returns GPO backup information from the default location stored in the global $GPBackupPath variable.
.EXAMPLE
PS C:\> Get-GPOBackup \\server01\backup\gpo -latest
Return the most recent backup for each GPO.
.EXAMPLE
PS C:\> Get-GPOBackup \\coredc01\backup\gpo -name "Ex*Laptop" -latest  | foreach {Import-GPO -TargetGuid $_.Guid -backupid $_.backupID -path $_.path}


DisplayName      : Executive Laptop
DomainName       : jdhlab.local
Owner            : JDHLAB\Domain Admins
Id               : af6f4a88-5e8a-49ce-84f7-f04677a7d80d
GpoStatus        : AllSettingsEnabled
Description      : configure C-level laptops
CreationTime     : 9/8/2010 8:36:10 AM
ModificationTime : 5/23/2011 9:52:43 AM
UserVersion      : AD Version: 2, SysVol Version: 2
ComputerVersion  : AD Version: 9, SysVol Version: 9
WmiFilter        :

Get the lastest version of the Executive Laptop GPO and import it back into Active Directory.
.NOTES
NAME        :  Get-GPOBackup
VERSION     :  1.4   
LAST UPDATED:  5/24/2011
AUTHOR      :  Jeffery Hicks
.LINK
Get-GPO 
Backup-GPO
.LINK
http://jdhitsolutions.com/blog/2011/05/get-gpo-backup/
.INPUTS
None
.OUTPUTS
Custom Object
#>

[cmdletbinding()]

Param(
    [Parameter(Position=0,Mandatory=$False,HelpMessage="What is the path to the GPO backup folder?")]
    [ValidateNotNullOrEmpty()]
    [string]$Path=$global:GPBackupPath,
    [Parameter(Position=1)]
    [string]$Name,
    [switch]$Latest
)

#validate $Path
if (-Not $Path) {
  $Path=Read-Host "What is the path to the GPO backup folder?"
 }

Try 
{
    Write-Verbose "Validating $Path"
    if (-Not (Test-Path $Path)) { Throw }
}
Catch 
{
    Write-Warning "Failed to find $Path"
    Break
}

#get each folder that looks like a GUID
[regex]$regex="^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$"

Write-Verbose "Enumerating folders under $Path"

#define an array to hold each backup object
$Backups=@()

#find all folders named with a GUID
Get-ChildItem -Path $path | Where {$_.name -Match $regex -AND $_.PSIsContainer} |
foreach {

  #import the Bkupinfo.xml file
  $file=Join-Path $_.FullName -ChildPath "bkUpinfo.xml"
  Write-Verbose "Importing $file"
  [xml]$data=Get-Content -Path $file 
  
  #parse the xml file for data
  $GPO=$data.BackupInst.GPODisplayName."#cdata-section"
  $GPOGuid=$data.BackupInst.GPOGuid."#cdata-section"
  $ID=$data.BackupInst.ID."#cdata-section"
  $Comment=$data.BackupInst.comment."#cdata-section"
  #convert backup time to a date time object
  [datetime]$Backup=$data.BackupInst.BackupTime."#cdata-section"
  $Domain=$data.BackupInst.GPODomain."#cdata-section"

  #write a custom object to the pipeline and add to the temporary array
  $Backups+=New-Object -TypeName PSObject -Property @{
    Name=$GPO
    Comment=$Comment
    #strip off the {} from the Backup ID GUID
    BackupID=$ID.Replace("{","").Replace("}","")
    #strip off the {} from the GPO GUID
    Guid=$GPOGuid.Replace("{","").Replace("}","")
    Backup=$Backup
    Domain=$Domain
    Path=$Path
  }

 } #foreach
 
 #if searching by GPO name, then filter and get just those GPOs
 if ($Name)
 {
    Write-Verbose "Filtering for GPO: $Name"
    $Backups=$Backups | where {$_.Name -like $Name}
 
 }
 
 Write-Verbose "Found $($Backups.Count) GPO Backups"
 
 #if -Latest then only write out the most current version of each GPO
 if ($Latest) 
 {
    Write-Verbose "Getting Latest Backups"
    $grouped=$Backups | Sort-Object -Property GUID | Group-Object -Property GUID
    $grouped | Foreach {
        $_.Group | Sort-Object -Property Backup | Select-Object -Last 1
    }
 }
 else
 {
    $Backups
 }
 
 Write-Verbose "Ending function"

} #end function