Make SharePoint designer workflow re-usable

# download SharePoint designer workflow from Site Assets
# and update solution and feature IDs to match previous version
$version = "2.0"

if($args -ne $null -and $args.Length -gt 0){
  $version = $args[0]
}

$origWspFile = "Workflow Process 2.0.wsp"
$destWspFile = $origWspFile.Replace("2.0.wsp", "$($version)_new.wsp")
$webFolder = "http://devintranet/sites/workflowssite/SiteAssets"
$workDir = "C:\DeploymentScripts\workflowssite\$($version)"
$destDir = "$($workDir)\WSP"

$webFile = "$($webFolder)/$($origWspFile)"
$wspFile = "$($workDir)\$($origWspFile)"
$userAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2;)"

Remove-Item -Recurse -Force $workDir -ErrorAction SilentlyContinue
New-Item  $workDir -type directory

set-location $workDir
$wc = New-Object System.Net.WebClient
$wc.UseDefaultCredentials = $true
$wc.Headers.Add("user-agent", $userAgent)
$wc.DownloadFile($webFile, $wspFile)

Remove-Item -Recurse -Force $destDir -ErrorAction SilentlyContinue
New-Item  $destDir -type directory
expand -R -F:* "$($origWspFile)" WSP

$fps = "$($destDir)\manifest.xml"
$xml = [xml](Get-Content $fps)
$xml.Solution.SolutionId = "{dd48ffd2-6ee3-4cba-94c0-721887f2ad1c}"
$xml.Save($fps)

$fpf1 = "$($destDir)\Workflow Process 2.0WebEventReceivers\Feature.xml"
$xml = [xml](Get-Content $fpf1)
$xml.Feature.Id = "{4be55305-1708-4a75-a537-2682e7c77550}"
# $xml.Feature.Version = "$($version).0.0"
$xml.Save($fpf1)


$fpf2 = "$($destDir)\Workflow Process 2.0ListInstances\Feature.xml"
$xml = [xml](Get-Content $fpf2)
$xml.Feature.Id = "{ea607063-4ad3-4414-b837-605794944cb2}"
$xml.Feature.Title = "Workflow Process Workflow"
# $xml.Feature.Version = "$($version).0.0"
$xml.Save($fpf2)


$len = $destDir.Length + 1
$files = Get-ChildItem $destDir -Recurse |?{ -not $_.PSIsContainer }|%{$_.FullName}|%{$_.SubString($len)}

$ddfTemplate = @"
;*** Diamond Directive File
;
;
.OPTION EXPLICIT                    ; Generate errors on variable typos
;
.Set CabinetNameTemplate=ppp.cab    ; The name of the WSP file
.set DiskDirectoryTemplate=CDROM    ; All cabinets go in a single directory
.Set CompressionType=MSZIP          ;
.Set Cabinet=on                     ;
.Set Compress=on                    ;
.Set DiskDirectory1=.               ; Use the specified directory for the output CAB file
;
;*** Disable size limits for wsp (cab) files ;
;
.Set CabinetFileCountThreshold=0
.Set FolderFileCountThreshold=0
.Set FolderSizeThreshold=0
.Set MaxCabinetSize=0
.Set MaxDiskFileCount=0
.Set MaxDiskSize=0
;
;*** Files to zip                   ;
;
"@

$lines = $ddfTemplate.Split([string[]]"`n",'None')


$ddfFilePath = "$($destDir)\solution.dff"
$stream =  New-Object System.IO.StreamWriter($ddfFilePath);
foreach($line in $lines){
  $stream.WriteLine($line)
}

foreach($file in $files){
  $stream.WriteLine("`"$($destDir)\$($file)`" `"$($file)`"")
}

$stream.Close()

set-location $destDir
makecab.exe /F solution.dff
Rename-Item ppp.cab "$($destWspFile)"