# NixOS Configuration

A modular NixOS flake configuration for managing multiple machines (kronos laptop, herra desktop) with a layered architecture and swappable desktop rices.

## Quick Start

```bash
# Apply configuration
sudo nixos-rebuild switch

# Test without applying
sudo nixos-rebuild test

# Validate syntax
nix flake check

# Preview changes
sudo nixos-rebuild dry-run
```

## Architecture

```
flake.nix                          # Entry point, defines inputs
  ↓
hosts/{kronos,herra}/              # Per-machine configs
  ├─ configuration.nix             # Machine identity
  └─ hardware-configuration.nix    # Hardware (autogenerated)

system/                            # System-wide config
  └─ default.nix                   # Orchestrator
      ├─ boot.nix, audio.nix, bluetooth.nix
      ├─ networking.nix, graphics.nix
      ├─ packages.nix, programs.nix, services.nix
      ├─ users.nix, nix.nix
      ├─ desktop.nix               # X11 + i3wm
      └─ stylix.nix                # Theming

home/mun/                          # User "mun" config
  └─ default.nix                   # User orchestrator
      ├─ programs/                 # git, ssh, zsh
      └─ (imports active rice)

home/rices/                        # Desktop rices
  ├─ nord-blue/                    # Current active rice
  └─ original/                     # Alternative rice
```

## Directory Structure

```
.
├── flake.nix                      # Flake inputs/outputs
├── flake.lock                     # Reproducibility lock
│
├── hosts/
│   ├── kronos/                    # Laptop
│   │   ├── configuration.nix
│   │   └── hardware-configuration.nix
│   └── herra/                     # Desktop (dual-boot)
│       ├── configuration.nix
│       └── hardware-configuration.nix
│
├── system/                        # System-wide modules
│   ├── default.nix                # Imports all system modules
│   ├── nix.nix                    # Nix settings, flakes
│   ├── boot.nix                   # Bootloader, kernel
│   ├── audio.nix                  # Pipewire
│   ├── bluetooth.nix              # Bluetooth
│   ├── networking.nix             # NetworkManager
│   ├── graphics.nix               # GPU drivers
│   ├── packages.nix               # System packages
│   ├── programs.nix               # System programs
│   ├── services.nix               # System services
│   ├── users.nix                  # User accounts
│   ├── desktop.nix                # X11 + i3wm
│   └── stylix.nix                 # Theme framework
│
└── home/
    ├── mun/                       # User "mun"
    │   ├── default.nix            # User orchestrator
    │   └── programs/
    │       ├── git.nix
    │       ├── ssh.nix
    │       └── zsh.nix
    │
    └── rices/                     # Desktop themes
        ├── nord-blue/             # Active rice
        │   ├── default.nix
        │   ├── variables.nix      # Colors, wallpaper
        │   ├── i3.nix
        │   ├── alacritty.nix
        │   ├── nvim.nix
        │   ├── helix.nix
        │   ├── picom.nix
        │   ├── fastfetch.nix
        │   └── wallpapers/
        │
        └── original/              # Alternative rice
            ├── default.nix
            ├── variables.nix
            ├── i3.nix
            ├── kitty.nix
            ├── polybar.nix
            ├── rofi.nix
            ├── dunst.nix
            ├── neovim.nix
            ├── nnn.nix
            ├── picom.nix
            ├── scripts.nix
            └── xdg.nix
```

## Configuration Layers

### 1. System Layer (`system/`)
Applied to all machines. Contains boot, networking, audio, graphics, packages, services, users, and desktop environment setup.

### 2. Machine Layer (`hosts/`)
Per-machine identity (hostname) and hardware configuration.

### 3. User Layer (`home/mun/`)
User-specific programs: git, ssh, zsh config, and imports the active rice.

### 4. Rice Layer (`home/rices/`)
Desktop theming: window manager config, terminal, editor, status bar, colors.

## Adding Configurations

**New system package:**
```nix
# system/packages.nix
environment.systemPackages = with pkgs; [
  # add here
];
```

**New system module:**
1. Create `system/mymodule.nix`
2. Add to `system/default.nix` imports

**New user program:**
1. Create `home/mun/programs/myprogram.nix`
2. Add to `home/mun/default.nix` imports

**New rice module:**
1. Create file in the active rice directory
2. Add to that rice's `default.nix` imports

## Switching Rices

Edit `home/mun/default.nix`:

```nix
imports = [
  ./programs/git.nix
  ./programs/ssh.nix
  ./programs/zsh.nix
  # Change rice here:
  ../rices/nord-blue      # current
  # ../rices/original     # alternative
];
```

Then rebuild: `sudo nixos-rebuild switch`

## Creating a New Rice

1. Create directory: `home/rices/my-rice/`
2. Create `default.nix` orchestrator
3. Create `variables.nix` with colors
4. Add application configs (i3.nix, terminal, etc.)
5. Import in `home/mun/default.nix`

## Machine-Specific Config

Each host has minimal configuration - just hostname and hardware:

```nix
# hosts/kronos/configuration.nix
{
  imports = [ ./hardware-configuration.nix ];
  networking.hostName = "kronos";
}
```

All shared config lives in `system/` and `home/`.

## Flake Inputs

- `nixpkgs` - NixOS 25.11
- `nixpkgs-unstable` - Latest packages via `pkgs.unstable.*`
- `home-manager` - 25.11
- `stylix` - Theming framework
- `fenix` - Rust toolchain