# OpenCore boot disk for build-time boots, derived from an image's ESP
# (makeOpenCore output) with build-only settings: extra boot-args (serial
# console, verbose) and optionally an OpenCore ScanPolicy so that only the PE
# (an HFS+ volume on SATA) is bootable — the build never lands on the wrong OS.
{ pkgs, lib, ... }:
{ esp, bootArgs ? null, scanPolicy ? null, name ? "boot" }:
pkgs.runCommand "${name}-bootdisk" {
  nativeBuildInputs = with pkgs; [ python3 mtools dosfstools gptfdisk ];
} ''
  cp -r ${esp}/EFI EFI
  chmod -R u+w EFI
  python3 - <<'PY'
  import plistlib
  p = 'EFI/OC/config.plist'
  cfg = plistlib.load(open(p, 'rb'))
  nv = cfg['NVRAM']['Add']['7C436110-AB2A-4BBB-A880-FE41995C9F82']
  ${lib.optionalString (bootArgs != null) ''nv['boot-args'] = ${builtins.toJSON bootArgs}''}
  ${lib.optionalString (scanPolicy != null) ''cfg['Misc']['Security']['ScanPolicy'] = ${toString scanPolicy}''}
  plistlib.dump(cfg, open(p, 'wb'))
  print('boot-args:', nv['boot-args'], 'ScanPolicy:', cfg['Misc']['Security']['ScanPolicy'])
  PY
  mkdir -p $out
  truncate -s 64M $out/boot.img
  sgdisk -n 1:2048:0 -t 1:EF00 -c 1:EFI $out/boot.img >/dev/null
  SECTORS=$(( 64*1024*1024/512 - 2048 - 34 ))
  mkfs.vfat -F 32 -n OPENCORE --offset 2048 $out/boot.img $(( SECTORS / 2 )) >/dev/null
  mcopy -i $out/boot.img@@1M -s EFI ::
  mdir -i $out/boot.img@@1M ::EFI/OC >/dev/null
''