<#
.SYNOPSIS
    Installs all available Windows Updates via PSWindowsUpdate module.

.DESCRIPTION
    Installs the PSWindowsUpdate module from PSGallery and runs a full
    Windows Update pass. Does not auto-reboot - the operator restarts
    manually after all deployment steps complete. Skips drivers (handled
    by step 11 Dell Command Update or Windows Update for Business).

.ITEMS
    nainstalovat-pswindowsupdate-modul: Installs NuGet provider and PSWindowsUpdate module from PSGallery. Required only on first run - subsequent runs reuse the cached module.
    spustit-windows-update-vsechny-aktualizace: Calls Install-WindowsUpdate -AcceptAll -IgnoreReboot. Installs all Quality, Security and Feature updates. Skips reboot - operator restarts manually after deployment completes.
#>
param(
    [object]$Config,
    [string]$LogFile
)

$ErrorActionPreference = "Continue"

function Write-Log {
    param([string]$Message, [string]$Level = "INFO")
    $line = "[$(Get-Date -Format 'HH:mm:ss')] [$Level] $Message"
    $null = New-Item -ItemType Directory -Force -Path (Split-Path $LogFile -Parent) -ErrorAction SilentlyContinue
    Add-Content -Path $LogFile -Value $line -Encoding UTF8
    Write-Output $line
}

Write-Log "=== Step 12 - Windows Update ===" -Level STEP

# -----------------------------------------------------------------------
# 1. NuGet provider (required for Install-Module from PSGallery)
# -----------------------------------------------------------------------
Write-Log "Installing NuGet provider..." -Level INFO
try {
    Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force -Scope AllUsers | Out-Null
    Write-Log "  NuGet provider ready" -Level OK
} catch {
    Write-Log "  NuGet provider install failed: $_" -Level WARN
}

# -----------------------------------------------------------------------
# 2. PSWindowsUpdate module
# -----------------------------------------------------------------------
Write-Log "Installing PSWindowsUpdate module..." -Level INFO
try {
    $existing = Get-Module -ListAvailable -Name PSWindowsUpdate | Select-Object -First 1
    if ($existing) {
        Write-Log "  PSWindowsUpdate $($existing.Version) already installed" -Level INFO
    } else {
        Install-Module -Name PSWindowsUpdate -Force -Scope AllUsers -AllowClobber | Out-Null
        Write-Log "  PSWindowsUpdate installed" -Level OK
    }
    Import-Module PSWindowsUpdate -Force
} catch {
    Write-Log "  PSWindowsUpdate module setup failed: $_" -Level ERROR
    Write-Log "  Skipping Windows Update step" -Level WARN
    exit 1
}

# -----------------------------------------------------------------------
# 3. Run Windows Update
# -----------------------------------------------------------------------
Write-Log "Checking for available updates..." -Level INFO

try {
    $updates = Get-WindowsUpdate -AcceptAll -IgnoreReboot 2>&1
    if (-not $updates) {
        Write-Log "  No updates available - system is up to date" -Level OK
    } else {
        $count = ($updates | Measure-Object).Count
        Write-Log "  Found $count update(s) - installing..." -Level INFO

        Install-WindowsUpdate -AcceptAll -IgnoreReboot -Verbose 2>&1 | ForEach-Object {
            if ($_ -match '\S') {
                Write-Log "  $_" -Level INFO
            }
        }

        Write-Log "  Windows Update complete ($count updates processed)" -Level OK
    }
} catch {
    Write-Log "  Windows Update failed: $_" -Level ERROR
    exit 1
}

Write-Log "Step 12 - Windows Update complete" -Level OK