# Register-GEEnforce.ps1 - Registers "GE Shopfloor Enforce" scheduled task.
#
# Idempotent: deletes an existing task with the same name first. Also
# unregisters the legacy per-type enforcer tasks so they don't race.
#
# Triggers (all run as SYSTEM, RunLevel=Highest):
#   - AtLogOn                  for first-boot catch-up
#   - Repetition every 5 min   for fleet auto-update (jittered start offset
#                              in the first 5 min window to spread 200 PCs)
#   - Shift-change windows     05:45, 13:45, 21:45 EST (30-min window each;
#                              handled by running the task at window start
#                              and letting the lib run anything not yet
#                              applied - Stage 2b will gate ApplyMode=Nightly
#                              entries to only fire inside a window).
#
# Called from Run-ShopfloorSetup.ps1 at imaging time. Also usable manually
# to re-register on an existing PC.

param(
    [string]$EnforcerPath = 'C:\Program Files\GE\Shopfloor\GE-Enforce.ps1'
)

$ErrorActionPreference = 'Stop'
$taskName = 'GE Shopfloor Enforce'
$legacyTasks = @(
    'GE Common Enforce',
    'GE Acrobat Enforce',
    'GE Shopfloor Machine Apps Enforce',
    'GE Machine Enforce',
    'GE CMM Enforce',
    'GE Keyence Enforce'
)

function Write-RegisterLog { param([string]$m) Write-Host "[Register-GEEnforce] $m" }

# Unregister legacy per-type enforcers so only GE-Enforce drives the fleet.
foreach ($name in $legacyTasks) {
    $t = Get-ScheduledTask -TaskName $name -ErrorAction SilentlyContinue
    if ($t) {
        Write-RegisterLog "Unregistering legacy task: $name"
        Unregister-ScheduledTask -TaskName $name -Confirm:$false -ErrorAction SilentlyContinue
    }
}

# Drop an existing copy of our own task (re-imaging idempotency).
$existing = Get-ScheduledTask -TaskName $taskName -ErrorAction SilentlyContinue
if ($existing) {
    Write-RegisterLog "Removing existing scheduled task: $taskName"
    Unregister-ScheduledTask -TaskName $taskName -Confirm:$false -ErrorAction SilentlyContinue
}

# --- Action ---
$action = New-ScheduledTaskAction `
    -Execute 'powershell.exe' `
    -Argument "-NoProfile -ExecutionPolicy Bypass -File `"$EnforcerPath`""

# --- Triggers ---
# Per-PC random offset [0, 5) min so 200 PCs don't all fire on :00/:05/:10/...
# Derived from hostname hash so the same PC always picks the same offset.
$hostHash = [System.BitConverter]::ToUInt32(
    [System.Security.Cryptography.MD5]::Create().ComputeHash(
        [System.Text.Encoding]::UTF8.GetBytes($env:COMPUTERNAME)), 0)
$offsetMin = $hostHash % 5     # 0..4

$startToday = (Get-Date -Hour 0 -Minute $offsetMin -Second 0).AddSeconds(0)

$logonTrigger = New-ScheduledTaskTrigger -AtLogOn
# Periodic every 5 minutes, repeating indefinitely, starting at the offset
$periodicTrigger = New-ScheduledTaskTrigger -Once -At $startToday -RepetitionInterval (New-TimeSpan -Minutes 5)

$shift1Trigger = New-ScheduledTaskTrigger -Daily -At '05:45'    # 3-to-1 shift
$shift2Trigger = New-ScheduledTaskTrigger -Daily -At '13:45'    # 1-to-2
$shift3Trigger = New-ScheduledTaskTrigger -Daily -At '21:45'    # 2-to-3

$triggers = @($logonTrigger, $periodicTrigger, $shift1Trigger, $shift2Trigger, $shift3Trigger)

# --- Principal + Settings ---
$principal = New-ScheduledTaskPrincipal -UserId 'SYSTEM' -LogonType ServiceAccount -RunLevel Highest
$settings  = New-ScheduledTaskSettingsSet `
    -AllowStartIfOnBatteries `
    -DontStopIfGoingOnBatteries `
    -StartWhenAvailable `
    -ExecutionTimeLimit (New-TimeSpan -Hours 1) `
    -MultipleInstances IgnoreNew

$description = "GE Shopfloor unified enforcer. Reads common + pc-type manifests from " +
               "\\tsgwp00525.wjs.geaerospace.net\shared\dt\shopfloor\, runs " +
               "Install-FromManifest.ps1 against each. Periodic 5-min jitter + " +
               "AtLogOn + 3x shift-change windows. Log: C:\Logs\Shopfloor\enforce-*.log"

Register-ScheduledTask `
    -TaskName $taskName `
    -Action $action `
    -Trigger $triggers `
    -Principal $principal `
    -Settings $settings `
    -Description $description | Out-Null

Write-RegisterLog "Registered '$taskName' (offset $offsetMin min)"
Write-RegisterLog "  Triggers: AtLogOn, every 5min, 05:45, 13:45, 21:45"
Write-RegisterLog "  Action:   powershell -File $EnforcerPath"