<#
.SYNOPSIS
    Collects Windows Update logs from a device into one zip file.
.DESCRIPTION
    On Windows 10/11 and Server 2016+, Windows Update writes ETW traces instead of a text
    log. This script runs Get-WindowsUpdateLog to turn them into a readable WindowsUpdate.log,
    adds the ConfigMgr client's update logs if the client is installed, optionally adds
    CBS.log and the raw .etl files, and zips the lot as COMPUTERNAME-WULogs-timestamp.zip.
    One missing log doesn't stop the rest from being collected.
.PARAMETER DestinationPath
    Folder (local or UNC) where the zip is saved.
.PARAMETER SkipConfigMgrLogs
    Don't collect WUAHandler.log, UpdatesDeployment.log and friends.
.PARAMETER IncludeCbsLog
    Also collect CBS.log, where servicing stack and install failures often show up.
.PARAMETER IncludeEtl
    Also collect the raw .etl trace files, for when someone else wants to decode them.
.EXAMPLE
    .\Export-WindowsUpdateLog.ps1
.EXAMPLE
    .\Export-WindowsUpdateLog.ps1 -DestinationPath \\sccm01\UpdateLogs$ -IncludeCbsLog
#>
[CmdletBinding()]
param(
    [ValidateNotNullOrEmpty()]
    [string]$DestinationPath = (Join-Path $env:SystemRoot 'Temp\UpdateLogs'),
    [switch]$SkipConfigMgrLogs,
    [switch]$IncludeCbsLog,
    [switch]$IncludeEtl
)

$stamp   = Get-Date -Format 'yyyyMMdd-HHmmss'
$name    = "$env:COMPUTERNAME-WULogs-$stamp"
$work    = Join-Path ([System.IO.Path]::GetTempPath()) $name
$notes   = [System.Collections.Generic.List[string]]::new()
$null    = New-Item -Path $work -ItemType Directory -Force

function Copy-LogSet {
    param([string]$Source, [string[]]$Filter, [string]$Label)
    if (-not (Test-Path -Path $Source)) { $notes.Add("$Label folder not found"); return }
    $target = Join-Path $work $Label
    $null = New-Item -Path $target -ItemType Directory -Force
    foreach ($pattern in $Filter) {
        foreach ($file in @(Get-ChildItem -Path $Source -Filter $pattern -File -ErrorAction SilentlyContinue)) {
            try { Copy-Item -Path $file.FullName -Destination $target -ErrorAction Stop }
            catch { $notes.Add("Couldn't copy $($file.Name): $($_.Exception.Message)") }
        }
    }
}

# 1. The main event: decode the ETW traces into WindowsUpdate.log.
if (Get-Command -Name Get-WindowsUpdateLog -ErrorAction SilentlyContinue) {
    try {
        Write-Verbose 'Decoding Windows Update ETW traces. This can take a minute or two.'
        Get-WindowsUpdateLog -LogPath (Join-Path $work 'WindowsUpdate.log') -ErrorAction Stop | Out-Null
    }
    catch { $notes.Add("Get-WindowsUpdateLog failed: $($_.Exception.Message)") }
}
else {
    # Pre-Windows 10 machines still write a plain text log.
    Copy-LogSet -Source $env:SystemRoot -Filter 'WindowsUpdate.log' -Label 'Legacy'
}

# 2. The ConfigMgr side of the story, if there is one.
if (-not $SkipConfigMgrLogs) {
    $ccmLogs = Join-Path $env:SystemRoot 'CCM\Logs'
    if (Test-Path -Path $ccmLogs) {
        Copy-LogSet -Source $ccmLogs -Label 'ConfigMgr' -Filter 'WUAHandler*.log', 'UpdatesDeployment*.log', 'UpdatesHandler*.log', 'UpdatesStore*.log', 'ScanAgent*.log'
    }
    else { Write-Verbose 'No ConfigMgr client logs on this device.' }
}

# 3. Optional extras.
if ($IncludeCbsLog) { Copy-LogSet -Source (Join-Path $env:SystemRoot 'Logs\CBS') -Filter 'CBS.log' -Label 'CBS' }
if ($IncludeEtl)    { Copy-LogSet -Source (Join-Path $env:SystemRoot 'Logs\WindowsUpdate') -Filter '*.etl' -Label 'ETL' }

if ($notes.Count) { Set-Content -Path (Join-Path $work 'collection-notes.txt') -Value $notes }

# 4. Zip it up and clean up after ourselves.
try {
    if (-not (Test-Path -Path $DestinationPath)) { $null = New-Item -Path $DestinationPath -ItemType Directory -Force -ErrorAction Stop }
    $zip = Join-Path $DestinationPath "$name.zip"
    Compress-Archive -Path (Join-Path $work '*') -DestinationPath $zip -ErrorAction Stop
    $fileCount = @(Get-ChildItem -Path $work -File -Recurse).Count
}
catch {
    Write-Error "Couldn't write the archive to ${DestinationPath}: $($_.Exception.Message)"
    Remove-Item -Path $work -Recurse -Force -ErrorAction SilentlyContinue
    exit 1
}
Remove-Item -Path $work -Recurse -Force -ErrorAction SilentlyContinue

foreach ($note in $notes) { Write-Warning $note }

[pscustomobject]@{
    ComputerName = $env:COMPUTERNAME
    ZipPath      = $zip
    Files        = $fileCount
    SizeMB       = [math]::Round((Get-Item -Path $zip).Length / 1MB, 2)
    Warnings     = $notes.Count
}