# Set-EventSaverScreensaver.ps1
#
# Enable the EventSaver shopfloor screensaver for EVERY user on the box. Runs
# under GE-Enforce (SYSTEM) every cycle.
#
# WHY THIS WAS REWRITTEN (2026-08-06)
# The previous version wrote the timeout to exactly two places: HKU\.DEFAULT,
# which only seeds profiles created AFTERWARDS, and the hive of one profile
# whose folder had to be named literally 'Shopfloor'. On any PC where the
# operator signs in as anything else, no HKCU was ever touched - the screensaver
# then ran on whatever the profile already carried (a domain default, commonly
# 120 seconds), while GE-Enforce reported success every cycle because from its
# point of view it had done its job.
#
# That is what the "screensaver after 2 minutes instead of 9" reports were: the
# manifest said 480 and the machines had never been told.
#
# Now: seed .DEFAULT for future profiles, then apply to EVERY loaded user hive.
# Same approach Set-DisplayAlwaysOn.ps1 already uses for the kiosks. A user who
# signs in between cycles is picked up on the next one.
#
# IDEMPOTENT + SILENT: hives already correct are skipped, so the common path
# writes nothing.

[CmdletBinding()]
param(
    [string]$ScrPath        = 'C:\Windows\System32\EventSaver.scr',
    [int]   $TimeoutSeconds = 540,
    # Retired. Kept so an older manifest passing -TargetUser does not fail to
    # bind; it is deliberately ignored - targeting one named account is the bug
    # this rewrite removes.
    [string]$TargetUser     = '',
    [string]$TaskName       = 'EventSaver-Enable'
)

$ErrorActionPreference = 'Continue'

$logDir = 'C:\Logs\Shopfloor'
if (-not (Test-Path $logDir)) { New-Item -ItemType Directory -Path $logDir -Force | Out-Null }
$log = Join-Path $logDir 'eventsaver.log'
function Write-Log($m) {
    Add-Content -LiteralPath $log -Value ("{0}  {1}" -f (Get-Date -Format 'yyyy-MM-dd HH:mm:ss'), $m)
}

function Get-Val($deskKey, $name) {
    return (Get-ItemProperty -Path $deskKey -Name $name -ErrorAction SilentlyContinue).$name
}

# Already what we want? Idempotency gate - keeps the common path silent.
function Saver-IsSet($deskKey) {
    if (-not (Test-Path $deskKey)) { return $false }
    if ((Get-Val $deskKey 'ScreenSaveActive') -ne '1') { return $false }
    if ((Get-Val $deskKey 'SCRNSAVE.EXE') -ne $ScrPath) { return $false }
    if ("$((Get-Val $deskKey 'ScreenSaveTimeOut'))" -ne "$TimeoutSeconds") { return $false }
    return $true
}

function Set-SaverValues($deskKey) {
    if (-not (Test-Path $deskKey)) { New-Item -Path $deskKey -Force | Out-Null }
    Set-ItemProperty -Path $deskKey -Name 'ScreenSaveActive'    -Value '1'               -Type String -Force
    Set-ItemProperty -Path $deskKey -Name 'SCRNSAVE.EXE'        -Value $ScrPath          -Type String -Force
    Set-ItemProperty -Path $deskKey -Name 'ScreenSaveTimeOut'   -Value "$TimeoutSeconds" -Type String -Force
    Set-ItemProperty -Path $deskKey -Name 'ScreenSaverIsSecure' -Value '0'               -Type String -Force
}

# --- 1. seed .DEFAULT so profiles created later start correct -----------------
$defKey = 'Registry::HKEY_USERS\.DEFAULT\Control Panel\Desktop'
if (-not (Saver-IsSet $defKey)) {
    try { Set-SaverValues $defKey; Write-Log "seeded .DEFAULT ($TimeoutSeconds s)" }
    catch { Write-Log "ERROR seeding .DEFAULT: $_" }
}

# --- 2. apply to every loaded human hive --------------------------------------
# Skipped: the three service accounts (SYSTEM, LOCAL SERVICE, NETWORK SERVICE)
# and the _Classes companions, which are not user desktops and would just add
# noise. Everything else that is loaded belongs to somebody signed in now.
$serviceSids = @('S-1-5-18', 'S-1-5-19', 'S-1-5-20')
$applied = 0
$already = 0

try {
    $hives = Get-ChildItem 'Registry::HKEY_USERS' -ErrorAction Stop | ForEach-Object { $_.PSChildName }
} catch {
    Write-Log "ERROR enumerating HKEY_USERS: $_"
    $hives = @()
}

foreach ($sid in $hives) {
    if ($sid -eq '.DEFAULT') { continue }              # handled above
    if ($sid -like '*_Classes') { continue }
    if ($serviceSids -contains $sid) { continue }
    if ($sid -notlike 'S-1-5-21-*') { continue }       # real domain/local users only

    $hiveKey = "Registry::HKEY_USERS\$sid\Control Panel\Desktop"
    if (Saver-IsSet $hiveKey) { $already++; continue }
    try {
        Set-SaverValues $hiveKey
        $applied++
        Write-Log "applied to hive $sid ($TimeoutSeconds s)"
    } catch {
        Write-Log "ERROR writing hive ${sid}: $_"
    }
}

if ($applied -eq 0 -and $already -eq 0) {
    # Nobody signed in - normal during imaging or on an idle bay. .DEFAULT above
    # covers the next profile, and the next cycle after a logon covers the rest.
    Write-Log 'no user hives loaded; .DEFAULT seeded, will apply on a later cycle'
}

# --- 3. remove the old per-user fallback task ---------------------------------
# The previous version registered an AtLogon task for the hardcoded 'Shopfloor'
# account. On machines where nobody signs in as that, it sat queued forever and
# never fired. Applying to loaded hives every cycle replaces it, so clear any
# that are still registered.
try {
    if (Get-ScheduledTask -TaskName $TaskName -ErrorAction SilentlyContinue) {
        Unregister-ScheduledTask -TaskName $TaskName -Confirm:$false -ErrorAction SilentlyContinue
        Write-Log "removed stale fallback task '$TaskName'"
    }
} catch { }

exit 0