$ErrorActionPreference = 'Stop'

$root = Split-Path -Parent $PSScriptRoot
$asset = Join-Path $root 'static/assets/modules/auth/opaque/a02-login-panel.png'

if (-not (Test-Path -LiteralPath $asset)) {
  throw 'Missing A02 login-panel asset'
}

Add-Type -AssemblyName System.Drawing
$bitmap = [System.Drawing.Bitmap]::FromFile($asset)
$width = [int]$bitmap.Width
$height = [int]$bitmap.Height
$corners = @(
  $bitmap.GetPixel(0, 0).A,
  $bitmap.GetPixel(($width - 1), 0).A,
  $bitmap.GetPixel(0, ($height - 1)).A,
  $bitmap.GetPixel(($width - 1), ($height - 1)).A
)
$bitmap.Dispose()

$ratio = [double]$width / $height
if ($width -ne 940 -or $height -ne 1672) { throw 'A02 login-panel asset must remain 940 x 1672px.' }
if ([Math]::Abs($ratio - 0.5622) -gt 0.001) { throw 'A02 login-panel asset must retain its approved panel ratio.' }
if (($corners | Where-Object { $_ -ne 255 }).Count -ne 0) { throw 'A02 login-panel asset must have opaque outer corners.' }

$agreementAssets = @(
  'static/assets/modules/auth/transparent/a02-agreement-unchecked.png',
  'static/assets/modules/auth/transparent/a02-agreement-checked.png'
)

foreach ($agreementAssetRelativePath in $agreementAssets) {
  $agreementAsset = Join-Path $root $agreementAssetRelativePath
  if (-not (Test-Path -LiteralPath $agreementAsset)) {
    throw "Missing A02 agreement asset: $agreementAssetRelativePath"
  }

  $agreementBitmap = [System.Drawing.Bitmap]::FromFile($agreementAsset)
  try {
    if ($agreementBitmap.Width -ne 96 -or $agreementBitmap.Height -ne 96) {
      throw "A02 agreement asset must be 96 x 96px: $agreementAssetRelativePath"
    }
    if (-not [System.Drawing.Image]::IsAlphaPixelFormat($agreementBitmap.PixelFormat)) {
      throw "A02 agreement asset must retain an alpha channel: $agreementAssetRelativePath"
    }
    $agreementCorners = @(
      $agreementBitmap.GetPixel(0, 0).A,
      $agreementBitmap.GetPixel(95, 0).A,
      $agreementBitmap.GetPixel(0, 95).A,
      $agreementBitmap.GetPixel(95, 95).A
    )
    if (($agreementCorners | Where-Object { $_ -ne 0 }).Count -ne 0) {
      throw "A02 agreement asset must have transparent outer corners: $agreementAssetRelativePath"
    }

    $hasOpaquePixel = $false
    for ($y = 0; $y -lt 96 -and -not $hasOpaquePixel; $y += 1) {
      for ($x = 0; $x -lt 96; $x += 1) {
        if ($agreementBitmap.GetPixel($x, $y).A -eq 255) {
          $hasOpaquePixel = $true
          break
        }
      }
    }
    if (-not $hasOpaquePixel) {
      throw "A02 agreement asset must contain an opaque icon: $agreementAssetRelativePath"
    }
  } finally {
    $agreementBitmap.Dispose()
  }
}

Write-Output 'A02-ASSET-ALPHA-AUDIT PASS'