Param($PackageDir, $LogDir)
if ($PSBoundParameters.Count -ne 2)  { Write-host "Error: -PackageDir <path> -LogDir <Path>" ;exit 1}
If ( -not (Test-Path $packagedir)) { Write-host "Error: -PackageDir <path> does not exist." ;exit 1}
If ( -not (Test-Path $LogDir)) { Write-host "Error: -LogDir <path> does not exist." ;exit 1}

function Write-Log {
  param (
      [string]$Message,
      [string]$LogPath = "$env:TEMP\sigupdate.log"
    )
  $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
  $entry = "[$timestamp] $Message"
  Add-Content -Path $LogPath -Value $entry
}

$LogPath = "$LogDir\$(hostname)_sigupdate.log"
if (Test-Path $logPath) {
  $logTime = (get-item $logPath).LastWriteTime
} else {
  $logTime = get-Date("1900/1/1")
}

Write-Log -Message "Start sigupdate.ps1" -LogPath $LogPath

$package = (Get-ChildItem -Path $packagedir| where {$_.name -eq "mpam-fe.exe"} | Sort Name | %{$_.FullName})
$currentSigVer = [version](Get-MpComputerStatus).AntivirusSignatureVersion

$success = $true
if ($package.Count -gt 0){
  $newSigVer = [version](Get-ItemProperty $package).VersionInfo.ProductVersion
  if ($newSigVer -gt $currentSigVer) {
    $outmsg = "Signature Update is starting... "
    $outmsg = $outmsg + "`nCurrent Signature Version: $currentSigVer"
    $outmsg = $outmsg + "`nNew Signature Version: $newSigVer"
    Write-Output $outmsg
    Write-Log -Message $outmsg -LogPath $LogPath
    Copy-Item $package -Destination "$env:TEMP\" -Force
    Start-Process "$env:TEMP\mpam-fe.exe" -Wait
    if (!($LASTEXITCODE -eq 0)) {
      $success = $false
      $package = "+ " + (Get-Item $package).Name + ": Failed"  
    } else {
      $package = "+ " + (Get-Item $package).Name  + ": Success"
    }
    Write-Output $package
    Write-Log -Message $package -LogPath $LogPath
    $outmsg = "Current Microsoft Defender Security intelligence:"
    $outmsg = $outmsg + "`nVersion: $((Get-MpComputerStatus).AntivirusSignatureVersion)"
    $outmsg = $outmsg + "`nEngine Version: $((Get-MpComputerStatus).AMEngineVersion)"
    $outmsg = $outmsg + "`nPlatform Version: $((Get-MpComputerStatus).AMProductVersion)"
    $outmsg = $outmsg + "`nLast Updated: $((Get-MpComputerStatus).AntivirusSignatureLastUpdated )"
    Write-Output $outmsg
    Write-Log -Message $outmsg -LogPath $LogPath
  } else {
    $outmsg = "No update."
    Write-Output $outmsg
    Write-Log -Message $outmsg -LogPath $LogPath
    exit 0
  }
}
exit 0