# Build a pre-installed Windows qcow2 image using QEMU unattended install.
# Boots into Audit Mode after install and shuts down.
# Apply templates via customizeImageFold to install software (auditScript)
# and customize registry (windowsRegistry), then generalize when done.
{ pkgs, lib, drivers, makeWinISO, makeAuditModeAutounattend, ... }:
{
  name ? "windows",
  upstreamISO,
  productKey ? "",
  imageIndex ? 1,
  diskSize ? "64G",
  bypassRequirements ? false,
  locale ? "en-US",
  efi ? true,
  smp ? 4,
  memSize ? 4096,
  vncDisplay ? null,  # e.g. ":10" to enable VNC on port 5910 for monitoring
  windowsVersionForVirtioDrivers ? "w10",  # "w10", "w11", "2k22", "2k19", etc.
}:
let
  AutounattendedXml = makeAuditModeAutounattend {
    inherit locale productKey imageIndex
            efi bypassRequirements windowsVersionForVirtioDrivers;
    diskIndex = 0;
    virtioDriverLetter = "E";
  };

  iso = makeWinISO {
    iso = upstreamISO;
    inherit AutounattendedXml;
  };

  displayArg = if vncDisplay != null then "-vnc ${vncDisplay}" else null;

  drv = pkgs.runCommand "${name}-vmix.qcow2" {
    __noChroot = true;
    requiredSystemFeatures = [ "kvm" ];
    nativeBuildInputs = with pkgs; [ qemu ];
  } ''
    echo "=== vmix: creating ${diskSize} disk ==="
    qemu-img create -f qcow2 disk.qcow2 ${diskSize}

    cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd
    chmod +w vars.fd

    echo "=== vmix: installing ${name} (unattended, 5-10 min) ==="

    VMIX_DISPLAY="-nographic"
    ${lib.optionalString (displayArg != null) ''VMIX_DISPLAY="${displayArg}"''}
    ${lib.optionalString (displayArg == null) ''
      VMIX_DF=$(ls -t /tmp/.vmix-display-* 2>/dev/null | head -1)
      if [ -n "$VMIX_DF" ]; then
        export DISPLAY=$(cat "$VMIX_DF")
        export HOME=$(mktemp -d)
        export XDG_RUNTIME_DIR=$HOME
        export SDL_VIDEODRIVER=x11
        VMIX_DISPLAY="-display sdl"
      fi
    ''}

    # Windows installs unattended, reboots into Audit Mode,
    # deletes cached Autounattend, shuts down → QEMU exits.
    QEMU_ARGS="-accel kvm -m ${toString memSize} -smp ${toString smp} -cpu host -machine type=q35 \
      -drive if=pflash,format=raw,readonly=on,file=${pkgs.OVMF.fd}/FV/OVMF_CODE.fd \
      -drive if=pflash,format=raw,file=vars.fd \
      -rtc base=localtime,clock=host \
      -device qemu-xhci -device usb-tablet \
      -drive file=disk.qcow2,format=qcow2,if=virtio \
      -drive file=${iso},media=cdrom,readonly=on \
      -drive file=${drivers.virtio-iso},media=cdrom,readonly=on \
      -nic user,model=virtio-net-pci"

    timeout 3600 qemu-system-x86_64 $VMIX_DISPLAY $QEMU_ARGS || \
      if [[ "$VMIX_DISPLAY" == "-display sdl" ]]; then
        echo "=== vmix: SDL failed, retrying headless ==="
        cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd && chmod +w vars.fd
        timeout 3600 qemu-system-x86_64 -nographic $QEMU_ARGS
      else
        exit 1
      fi

    echo "=== vmix: ${name} install complete ==="
    mv disk.qcow2 $out
  '';
in drv // { _vmixOsType = "windows"; }