# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

NixOS flake configuration for multiple machines (kronos, herra, mystra) using NixOS 25.11 and Home Manager 25.11. Features a layered architecture with swappable desktop rices.

## Common Commands

```bash
# Apply configuration (full rebuild and activation)
sudo nixos-rebuild switch

# Test configuration without making it the default boot option
sudo nixos-rebuild test

# Validate flake syntax and check for errors
nix flake check

# Preview what changes would be made
sudo nixos-rebuild dry-run

# Update flake inputs to latest versions
nix flake update

# Update specific input (e.g., nixpkgs)
nix flake lock --update-input nixpkgs

# Build for specific host
sudo nixos-rebuild switch --flake .#kronos
sudo nixos-rebuild switch --flake .#herra
sudo nixos-rebuild switch --flake .#mystra
```

## Architecture

```
flake.nix                             # Entry point - assigns rices to hosts
  ↓
hosts/{kronos,herra,mystra}/          # Per-machine (hostname + hardware)
  ↓
system/                               # System-wide config (base only)
  └─ boot, audio, bluetooth, networking, graphics
     packages, programs, services, users, nix
  ↓
home/rices/{rice}/system.nix          # Rice-level system config
  └─ desktop.nix (X11 + i3wm)         # Desktop environment
     stylix.nix (theming)             # Colors, fonts, cursor
  ↓
home/mun/                             # User config
  ├─ programs/                        # git, ssh, zsh
  └─ (imports rice via specialArgs)
  ↓
home/rices/{rice}/default.nix         # Rice home-manager modules
  └─ alacritty, i3, nvim, helix, picom, etc.
```

## Key Files

- `flake.nix` - Entry point: defines inputs and outputs, assigns rices to hosts in `nixosConfigurations` (e.g., `kronos = mkSystem "kronos" "nord-blue"`)
- `hosts/*/configuration.nix` - Per-machine config (hostname, hardware imports, machine-specific overrides)
- `hosts/herra/configuration.nix` - Desktop: dual-boot with Windows 11 (GRUB OS prober), Zen kernel override
- `system/default.nix` - System module orchestrator (imports base system modules only, no desktop/stylix)
- `system/packages.nix` - System-wide packages
- `home/mun/default.nix` - User orchestrator: imports user programs and rice via `${rice}` specialArg
- `home/rices/*/system.nix` - Rice-level system config (desktop environment + stylix theming)
- `home/rices/*/default.nix` - Rice home-manager modules orchestrator
- `home/rices/*/variables.nix` - Rice color definitions (optional, some rices use system.nix for colors)

## Adding Configurations

**New system package:** Add to `system/packages.nix` under `environment.systemPackages`

**New user package:** Add to `home/mun/default.nix` under `home.packages` (supports fenix Rust toolchain, TeX Live combinations, RetroArch cores)

**New system module:** Create in `system/`, add to `system/default.nix` imports

**New user program:** Create in `home/mun/programs/`, add to `home/mun/default.nix` imports

**New rice module:** Create in target rice directory (e.g., `home/rices/nord-blue/mymodule.nix`), add to that rice's `default.nix` imports

**New rice:**
1. Create `home/rices/my-rice/` directory
2. Create `system.nix` with desktop environment and stylix config
3. Create `default.nix` (imports home-manager modules)
4. Create app-specific configs (i3.nix, terminal.nix, etc.)
5. Optional: create `variables.nix` for shared color variables

## Switching Rices

Rices are assigned per-host in `flake.nix`. Edit the `nixosConfigurations` section:

```nix
nixosConfigurations = {
  kronos = mkSystem "kronos" "nord-blue";    # Laptop uses nord-blue
  herra = mkSystem "herra" "cosmic";         # Desktop uses cosmic
  mystra = mkSystem "mystra" "nord-blue";    # Another machine uses nord-blue
};
```

Then rebuild: `sudo nixos-rebuild switch`

Each rice is imported twice:
1. **System-level**: `home/rices/${rice}/system.nix` imported in flake (desktop + stylix)
2. **Home-level**: `home/rices/${rice}` imported in `home/mun/default.nix` via specialArgs (app configs)

## Important Architecture Details

**Overlays:** Flake provides `pkgs.unstable.*` for accessing bleeding-edge packages from nixpkgs-unstable while staying on stable 25.11

**NixOwOs Integration:** Enabled in `home/mun/default.nix` for NixOS branding/theming (os-release customization, overlays)

**Machine Separation:** Host configs are intentionally minimal (hostname + hardware-configuration import + optional overrides). All shared system config lives in `system/`, all shared user config in `home/mun/`

**Rice Architecture:** Rices span both system and home-manager:
- `system.nix` in each rice configures desktop environment (X11 + i3wm) and stylix theming
- `default.nix` in each rice imports home-manager modules (terminal, editor, compositor, etc.)
- System-level desktop/stylix was moved from `system/` to per-rice to allow different DEs per rice

**Stylix:** System-level theming framework imported at flake level, configured in each rice's `system.nix` (base16 colors, fonts, cursor, opacity, wallpaper)

**mkSystem Helper:** The `mkSystem` function in flake.nix takes (hostname, rice) and:
1. Imports host config from `hosts/${hostname}/configuration.nix`
2. Imports base system modules from `system/`
3. Imports rice system config from `home/rices/${rice}/system.nix`
4. Passes rice name to home-manager via specialArgs for user-level rice import

**Available Rices:**
- `nord-blue` - Complete: alacritty, i3, nvim, helix, picom, fastfetch
- `original` - Complete: kitty, i3, polybar, rofi, dunst, neovim, nnn, picom
- `cosmic` - Minimal/incomplete: only fluxbox.nix (work in progress)