PowerShell Script to Clean Up Old Files and Alert on High Disk Usage

param(
  [string]$TargetPath = "C:\Logs",
  [int]$DaysOld = 14,
  [string]$LogFile = "C:\Logs\homelab_cleanup.log",
  [string]$DriveLetter = "C",
  [int]$DiskThreshold = 85,
  [switch]$WhatIf
)

function Write-Log {
  param([string]$Message)
  $ts = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
  "$ts $Message" | Out-File -FilePath $LogFile -Append -Encoding utf8
}

Write-Log "=== Cleanup start ==="
Write-Log "TargetPath=$TargetPath DaysOld=$DaysOld Drive=$DriveLetter Threshold=${DiskThreshold}% WhatIf=$($WhatIf.IsPresent)"

if (-not (Test-Path $TargetPath)) {
  throw "TargetPath does not exist: $TargetPath"
}

$cutoff = (Get-Date).AddDays(-$DaysOld)

$files = Get-ChildItem -Path $TargetPath -File -Recurse -ErrorAction SilentlyContinue |
  Where-Object { $_.LastWriteTime -lt $cutoff }

Write-Log "Found $($files.Count) files older than $DaysOld days."

if ($files.Count -gt 0) {
  if ($WhatIf) {
    Write-Log "WHATIF: Listing files that would be deleted:"
    $files.FullName | ForEach-Object { Write-Log $_ }
  } else {
    foreach ($f in $files) {
      try {
        Remove-Item -LiteralPath $f.FullName -Force -ErrorAction Stop
        Write-Log "Deleted: $($f.FullName)"
      } catch {
        Write-Log "ERROR deleting $($f.FullName): $($_.Exception.Message)"
      }
    }
  }
}

$drive = Get-CimInstance Win32_LogicalDisk -Filter "DeviceID='$DriveLetter`:'"
$usedPct = [math]::Round((($drive.Size - $drive.FreeSpace) / $drive.Size) * 100, 0)

Write-Log "Disk usage on ${DriveLetter}: is ${usedPct}%."

if ($usedPct -ge $DiskThreshold) {
  Write-Log "ALERT: Disk usage high (${usedPct}% >= ${DiskThreshold}%)."
  Write-Output "ALERT: Disk usage high on ${DriveLetter}: (${usedPct}%)."
}

Write-Log "=== Cleanup end ==="