param(
  [string]$DriveRoot = (Resolve-Path "$PSScriptRoot\..\..").Path,
  [string]$ManifestPath = "manifest\gguf-downloads.json"
)
$ErrorActionPreference = 'Stop'
Set-Location $DriveRoot
$full = Join-Path $DriveRoot $ManifestPath
if (!(Test-Path $full)) { throw "Missing $ManifestPath. Create it from manifest\gguf-downloads.example.json." }
$m = Get-Content $full -Raw | ConvertFrom-Json
New-Item -ItemType Directory -Force -Path "$DriveRoot\models\gguf" | Out-Null
foreach ($item in $m.files) {
  $out = Join-Path $DriveRoot $item.path
  New-Item -ItemType Directory -Force -Path (Split-Path $out -Parent) | Out-Null
  Write-Host "Downloading $($item.name)"
  Invoke-WebRequest -Uri $item.url -OutFile $out
  if ($item.sha256) {
    $h = (Get-FileHash $out -Algorithm SHA256).Hash.ToLowerInvariant()
    if ($h -ne $item.sha256.ToLowerInvariant()) { throw "SHA256 mismatch for $($item.name)" }
  }
}