# Migrating an existing NixOS install to Nomarchy

You already have NixOS running and you want the Nomarchy desktop without
reformatting. This is the in-place path. Your `/`, `/home`, hostname, and
user account are preserved; Nomarchy is layered on as a flake input.

> Prefer a clean disk? Skip to the [fallback](#fallback-clean-install-via-the-live-iso).

---

## Prerequisites

- NixOS 25.11. Older releases are not supported by the current Nomarchy
  modules.
- Flakes enabled. If you don't have them yet:
  ```nix
  # somewhere in your existing config
  nix.settings.experimental-features = [ "nix-command" "flakes" ];
  ```
  Apply with `sudo nixos-rebuild switch` once before proceeding.

---

## 1. Move to a flake-based config

If you already have `/etc/nixos/flake.nix`, skip to step 2.

Back your existing config up:

```bash
sudo cp /etc/nixos/configuration.nix /etc/nixos/configuration.nix.bak
```

Then create `/etc/nixos/flake.nix` with the structure below. (This is the
same shape the Nomarchy installer produces — see
`installer/install.sh:generate_flake_config` in the upstream repo.)

```nix
{
  description = "My Nomarchy Configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
    nomarchy.url = "git+https://git.bemagri.xyz/bernardo/Nomarchy.git";
    # …or pin: "git+https://git.bemagri.xyz/bernardo/Nomarchy.git?rev=<sha>"
    nixos-hardware.url = "github:NixOS/nixos-hardware/master";
    home-manager = {
      url = "github:nix-community/home-manager/release-25.11";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, nomarchy, home-manager, nixos-hardware, ... }@inputs:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs {
        inherit system;
        overlays = [ nomarchy.overlays.default ];
        config.allowUnfree = true;
      };
    in
    {
      nixosConfigurations.<hostname> = nixpkgs.lib.nixosSystem {
        inherit pkgs;
        specialArgs = { inputs = nomarchy.inputs // inputs; };
        modules = [
          ./hardware-configuration.nix
          nomarchy.nixosModules.system
          ./system.nix
        ];
      };

      homeConfigurations.<user> = home-manager.lib.homeManagerConfiguration {
        inherit pkgs;
        extraSpecialArgs = { inputs = nomarchy.inputs // inputs; };
        modules = [
          nomarchy.nixosModules.home
          ./home.nix
          {
            home.username = "<user>";
            home.homeDirectory = "/home/<user>";
            home.stateVersion = "25.11";
          }
        ];
      };
    };
}
```

Replace `<hostname>` and `<user>` with your real values. Two-track Nomarchy:
the system block uses `nomarchy.nixosModules.system`; the standalone
home-manager block uses `nomarchy.nixosModules.home`. Both consume the same
`pkgs` so overlays stay in sync.

## 2. Move your existing settings into `system.nix` and `home.nix`

The Nomarchy installer also generates these files — copy that template, or
create minimal versions to start:

`/etc/nixos/system.nix`:

```nix
{ pkgs, ... }:
{
  networking.hostName = "<hostname>";
  time.timeZone = "<your-timezone>";

  users.users."<user>" = {
    isNormalUser = true;
    extraGroups = [ "wheel" "video" "render" "audio" "networkmanager" ];
  };

  # Compressed RAM swap — near-free memory headroom.
  zramSwap.enable = true;

  system.stateVersion = "25.11";
}
```

`/etc/nixos/home.nix`:

```nix
{ pkgs, ... }:
{
  home.packages = with pkgs; [
    btop
    fastfetch
    chromium
    # …add anything you want; firefox/thunar/mpv/mako/etc. ship with Nomarchy.
  ];
}
```

Move any user/services/packages you had in `configuration.nix` over to
`system.nix`. Do **not** redefine things Nomarchy already provides (display
manager, Hyprland, PipeWire, NetworkManager) unless you want to override
them — see the [conflicts](#conflicts-to-resolve-before-rebuild) section.

## 3. (Optional) Pick up hardware-specific tuning

Nomarchy ships a `nixos-hardware` matcher. From any shell on your existing
system:

```bash
nix shell nixpkgs#git -c \
  bash -c 'tmp=$(mktemp -d); git clone --depth=1 https://git.bemagri.xyz/bernardo/Nomarchy.git "$tmp" >/dev/null 2>&1; \
           source "$tmp/installer/hardware-db.sh"; nomarchy_detect_hw'
```

Output is a list like:

```
MODULE common-cpu-amd
MODULE common-gpu-amd
MODULE common-pc-laptop
MODULE framework-13-amd-ai-300-series
OPT    isFramework=true
```

Drop a `hardware-selection.nix` next to your flake:

```nix
{ inputs, ... }:
{
  imports = [
    inputs.nixos-hardware.nixosModules.common-cpu-amd
    inputs.nixos-hardware.nixosModules.common-gpu-amd
    inputs.nixos-hardware.nixosModules.framework-13-amd-ai-300-series
  ];
  nomarchy.hardware.isFramework = true;
}
```

…and add `./hardware-selection.nix` to the system module list in `flake.nix`.
Skip this entirely if you don't have a matching device.

## 4. Rebuild

```bash
sudo nixos-rebuild switch --flake /etc/nixos#<hostname>
home-manager switch --flake /etc/nixos#<user> --impure
```

Reboot or `systemctl restart display-manager`. SDDM comes up with the
Nomarchy theme; logging in as `<user>` lands you in Hyprland with the full
Nomarchy desktop.

After this, the daily workflow is two commands:

- **System changes** (services, kernel, hardware) →
  `sudo nixos-rebuild switch --flake /etc/nixos#<hostname>`
- **Dotfiles, themes, user packages** → `nomarchy-env-update` (runs the
  standalone `home-manager switch` for you, no system rebuild)

---

## Conflicts to resolve before rebuild

`nomarchy.nixosModules.system` enables a desktop stack. If your existing
`configuration.nix` already configures any of these, only one setting wins
and it's whichever has higher Nix priority. Fix these explicitly:

| Area | Nomarchy default | What to do if you already have it |
| --- | --- | --- |
| Display manager | SDDM (Wayland) | Disable yours: `services.xserver.displayManager.gdm.enable = lib.mkForce false;` (or whatever you had) |
| Default session | `hyprland-uwsm` | Drop your `services.displayManager.defaultSession` |
| Hyprland | `programs.hyprland.enable = true; withUWSM = true;` | Drop your `programs.hyprland` setting |
| Audio | PipeWire (alsa+pulse+jack) | Remove `services.pulseaudio.enable = true;` — NixOS errors if both are on |
| Networking | NetworkManager | Drop `networking.wireless.enable = true;` (if set) |
| Graphics | `hardware.graphics.enable = true` (was `hardware.opengl`) | Probably already enabled — fine |
| User groups | needs `video render networkmanager` | Add to your `users.users.<user>.extraGroups` |
| `/etc/os-release` | `ID=nomarchy`, `NAME=Nomarchy` | A few third-party scripts grep `ID=nixos` — adjust them or rely on `ID_LIKE` (TBD) |
| autoLogin | `enable = true; user = "nomarchy";` (mkDefault) | Override with `services.displayManager.autoLogin.user = "<your user>"` or disable |

Impermanence is **off** unless you set `nomarchy.system.impermanence.enable = true`,
and it requires a BTRFS layout with a `root-blank` snapshot. Don't enable it
on an existing install — the live ISO is the right path for that.

If your first rebuild errors out, the five most common failures and their fixes
live in [Troubleshooting](TROUBLESHOOTING.md).

---

## Fallback: clean install via the live ISO

```bash
# In a checkout of the Nomarchy repo:
nomarchy-test-live-iso       # boots the ISO in QEMU to evaluate
# Or burn the produced .iso to a USB and boot it on real hardware.
```

The ISO autologins to a Hyprland live session that points you at:

- `sudo /etc/install.sh` — install (BTRFS + LUKS + subvolumes per
  `installer/disko-config.nix`, auto-detects hardware via `hardware-db.sh`,
  runs `home-manager switch` inside `nixos-enter` so the first login is
  fully themed).
- `sudo /etc/install.sh --dry-run` — generate the flake into a tmpdir and
  parse-check it without touching the disk.
- `sudo /etc/install.sh --resume` — pick up an interrupted run.

After install, the system at `/etc/nixos/` is the same shape this guide
produces by hand.

---

## Verification (in-place migration)

1. `cat /etc/os-release` → `NAME=Nomarchy`, `ID=nomarchy`.
2. SDDM theme is the Nomarchy purple/blue panel.
3. After login: waybar shows the Nomarchy logo on the left, theme switcher
   under Style → Theme works.
4. `which btop fastfetch waybar walker nomarchy-env-update` → all on PATH.
5. `nomarchy-env-update` returns clean (proves standalone HM is wired and
   `nomarchy.nixosModules.home` is in scope).

If anything is wrong, your old config is intact at
`/etc/nixos/configuration.nix.bak` — `sudo nixos-rebuild switch -I nixos-config=/etc/nixos/configuration.nix.bak`
will roll back.