{
  description = "vmix — composable QEMU VM image building and orchestration";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
  };

  outputs = { self, nixpkgs, ... }:
  let
    system = "x86_64-linux";
    pkgs = import nixpkgs {
      inherit system;
      config.allowUnfree = true;
    };
    lib = pkgs.lib;
    vmixLib = import ./lib { inherit pkgs lib system; };
  in {
    overlays.default = import ./overlay.nix;

    nixosModules.default = import ./module.nix;

    lib.${system} = vmixLib;

    packages.${system} = {
      toDisk = pkgs.writeShellScriptBin "vmix-to-disk" ''
        set -euo pipefail

        usage() {
          echo "Usage: vmix-to-disk <qcow2-image> <target-disk>"
          echo ""
          echo "Write a vmix qcow2 image to a physical disk and expand the Windows partition."
          echo ""
          echo "Examples:"
          echo "  vmix-to-disk /nix/store/...-win10-ltsc-vmix.qcow2 /dev/sda"
          echo "  vmix-to-disk ./my-image.qcow2 /dev/nvme0n1"
          exit 1
        }

        [[ ''${#} -ne 2 ]] && usage

        IMAGE="$1"
        DISK="$2"

        [[ $EUID -ne 0 ]] && { echo "Error: must run as root"; exit 1; }
        [[ ! -f "$IMAGE" ]] && { echo "Error: image not found: $IMAGE"; exit 1; }
        [[ ! -b "$DISK" ]] && { echo "Error: not a block device: $DISK"; exit 1; }

        if ${pkgs.util-linux}/bin/mount | grep -q "^''${DISK}"; then
          echo "Error: $DISK has mounted partitions — unmount first"
          exit 1
        fi

        DISK_SIZE=$(${pkgs.util-linux}/bin/blockdev --getsize64 "$DISK")
        DISK_SIZE_GB=$(( DISK_SIZE / 1024 / 1024 / 1024 ))

        echo "=== vmix to physical disk ==="
        echo "Image:  $IMAGE"
        echo "Target: $DISK ($DISK_SIZE_GB GB)"
        echo ""
        echo "WARNING: This will DESTROY all data on $DISK"
        read -rp "Continue? [y/N] " confirm
        [[ "$confirm" != "y" && "$confirm" != "Y" ]] && { echo "Aborted."; exit 0; }

        echo ""
        echo "[1/4] Writing image to disk..."
        ${pkgs.qemu}/bin/qemu-img convert -p -f qcow2 -O raw "$IMAGE" "$DISK"

        echo "[2/4] Fixing GPT backup header..."
        ${pkgs.gptfdisk}/bin/sgdisk -e "$DISK"

        echo "[3/4] Expanding Windows partition (partition 3) to fill disk..."
        ${pkgs.parted}/bin/parted -s "$DISK" resizepart 3 100%

        # detect partition device name (nvme/mmcblk use p3, others use 3)
        if [[ "$DISK" == *nvme* ]] || [[ "$DISK" == *mmcblk* ]]; then
          WIN_PART="''${DISK}p3"
        else
          WIN_PART="''${DISK}3"
        fi

        echo "[4/4] Expanding NTFS filesystem on $WIN_PART..."
        ${pkgs.ntfs3g}/bin/ntfsresize --force --no-action "$WIN_PART"
        echo "y" | ${pkgs.ntfs3g}/bin/ntfsresize --force "$WIN_PART"

        echo ""
        echo "Done. Windows partition expanded to fill $DISK."
        echo "You can now boot from the disk."
      '';
    };

    apps.${system}.toDisk = {
      type = "app";
      program = "${self.packages.${system}.toDisk}/bin/vmix-to-disk";
    };
  };
}