Nomarchy/modules/nixos/default.nix

# Nomarchy — reusable system layer (NixOS 26.05).
#
# This module is the distro: import it from any host (see
# nixosModules.nomarchy in flake.nix) and layer your machine specifics
# (bootloader, hostname, users, hardware) on top. Host concerns are
# deliberately NOT set here. Everything user-facing (Hyprland config,
# Waybar, Ghostty, theming) lives in modules/home.
{ config, lib, pkgs, ... }:

let
  cfg = config.nomarchy.system;
in
{
  imports = [ ./options.nix ./plymouth.nix ./file-manager.nix ];

  config = {
    # The safe half of distro branding: distroName flows into
    # /etc/os-release PRETTY_NAME, systemd-boot entry titles and the
    # ISO boot-menu label. distroId stays "nixos" on purpose — it feeds
    # DEFAULT_HOSTNAME and upstream isNixos checks (see roadmap).
    system.nixos.distroName = lib.mkDefault "Nomarchy";

    # Unfree allowed distro-wide: pragmatic-desktop territory (vendor
    # GPU/wifi drivers, firmware, fonts, …). The custom nixpkgs-config
    # type can't carry a nested mkDefault; disagree with
    # `nixpkgs.config = lib.mkForce { allowUnfree = false; }`.
    nixpkgs.config.allowUnfree = true;

    # ── Wayland session: Hyprland ────────────────────────────────────
    # Installs the binary, registers the session, wires up
    # xdg-desktop-portal-hyprland. Configuration is Home Manager's job.
    programs.hyprland.enable = lib.mkDefault true;

    xdg.portal = {
      enable = lib.mkDefault true;
      extraPortals = [ pkgs.xdg-desktop-portal-gtk ]; # file pickers, etc.
    };

    services.greetd = lib.mkIf cfg.greeter.enable {
      enable = lib.mkDefault true;
      settings = {
        default_session = {
          # start-hyprland is Hyprland 0.55's watchdog launcher; running
          # the bare binary makes every session print a warning.
          command = lib.mkDefault "${pkgs.tuigreet}/bin/tuigreet --time --remember --cmd start-hyprland";
          user = "greeter";
        };
        # Boot straight into the session once; logout → normal greeter.
        initial_session = lib.mkIf (cfg.greeter.autoLogin != null) {
          command = "start-hyprland";
          user = cfg.greeter.autoLogin;
        };
      };
    };

    # ── Audio: Pipewire ──────────────────────────────────────────────
    security.rtkit.enable = lib.mkDefault cfg.audio.enable;
    services.pulseaudio.enable = lib.mkDefault false;
    services.pipewire = lib.mkIf cfg.audio.enable {
      enable = lib.mkDefault true;
      alsa.enable = true;
      alsa.support32Bit = true;
      pulse.enable = true;
      wireplumber.enable = true;
    };

    # ── Desktop services ─────────────────────────────────────────────
    security.polkit.enable = lib.mkDefault true;
    services.gnome.gnome-keyring.enable = lib.mkDefault true;
    services.dbus.enable = lib.mkDefault true;
    services.upower.enable = lib.mkDefault true;
    networking.networkmanager.enable = lib.mkDefault true;

    # zsh as the default login shell (the desktop's shell experience —
    # starship/bat/eza/zoxide — is configured home-side in shell.nix).
    # programs.zsh.enable wires /etc/zshrc, completion and /etc/shells;
    # defaultUserShell applies to normal users that don't set their own.
    programs.zsh.enable = lib.mkDefault true;
    # mkOverride 500: beats nixpkgs' bash.nix `mkDefault bashInteractive`
    # (equal mkDefault priority would conflict) while staying below a
    # plain downstream assignment. A per-user `users.users.<n>.shell`
    # overrides this regardless.
    users.defaultUserShell = lib.mkOverride 500 pkgs.zsh;

    hardware.bluetooth.enable = lib.mkDefault cfg.bluetooth.enable;
    services.blueman.enable = lib.mkDefault cfg.bluetooth.enable;

    # ── Foreign binaries: nix-ld ─────────────────────────────────────
    # An ld.so shim so dynamically-linked binaries not built for NixOS
    # (downloaded tools, language servers, pip/npm-installed ELFs, the
    # npx-fetched claude-code) run without manual patchelf. On by default —
    # a pragmatic-desktop expectation.
    programs.nix-ld.enable = lib.mkDefault true;

    # ── Firmware ─────────────────────────────────────────────────────
    # Blobs for in-kernel drivers: wifi (iwlwifi/ath/rtw/brcm), SOF
    # audio, Bluetooth. Drivers ship with the kernel, but without these
    # a real machine can boot with no wifi — QEMU never catches it.
    # nixos-generate-config also keys CPU microcode off this flag.
    hardware.enableRedistributableFirmware = lib.mkDefault true;

    # ── BTRFS timeline snapshots (ported from the previous iteration) ─
    # Guarded on the actual filesystem so enabling it on an ext4 machine
    # is a clean no-op rather than a failing timer.
    services.snapper.configs = lib.mkIf
      (cfg.snapper.enable && (config.fileSystems."/".fsType or "") == "btrfs")
      {
        root = {
          SUBVOLUME = "/";
          TIMELINE_CREATE = true;
          TIMELINE_CLEANUP = true;
          TIMELINE_LIMIT_HOURLY = "5";
          TIMELINE_LIMIT_DAILY = "7";
          TIMELINE_LIMIT_WEEKLY = "0";
          TIMELINE_LIMIT_MONTHLY = "0";
          TIMELINE_LIMIT_YEARLY = "0";
        };
      };

    # ── Fonts ────────────────────────────────────────────────────────
    # The ten most popular Nerd Fonts ship by default, so any of them
    # can be named in the theme state's fonts.mono and actually resolve
    # (nomarchy-theme-sync warns when a configured font is missing).
    fonts = {
      packages = with pkgs; [
        nerd-fonts.jetbrains-mono
        nerd-fonts.fira-code
        nerd-fonts.caskaydia-cove
        nerd-fonts.hack
        nerd-fonts.sauce-code-pro
        nerd-fonts.meslo-lg
        nerd-fonts.roboto-mono
        nerd-fonts.ubuntu-mono
        # iosevka would be next by popularity, but its package is 1.1 GB
        # (every weight × variant) — too heavy for the ISO and closures.
        nerd-fonts.mononoki
        nerd-fonts.inconsolata
        inter
        noto-fonts
        noto-fonts-color-emoji
        # The legacy-ported waybar identities (summer-day/night) use
        # FontAwesome codepoints in their layouts and list it in css.
        font-awesome
      ];
      fontconfig.defaultFonts = {
        monospace = lib.mkDefault [ "JetBrainsMono Nerd Font" ];
        sansSerif = lib.mkDefault [ "Inter" ];
        emoji = lib.mkDefault [ "Noto Color Emoji" ];
      };
    };

    # ── Essential packages ───────────────────────────────────────────
    environment.systemPackages = with pkgs; [
      nomarchy-theme-sync # provided by overlays.default

      # Friendly wrappers for the two rebuild paths (README §3). Run as
      # your user: `nix flake update` must NOT run as root (libgit2
      # refuses the user-owned flake repo) — sudo happens inside, only
      # for the system switch.
      (pkgs.writeShellScriptBin "sys-update" ''
        set -e
        if [ "$(id -u)" -eq 0 ]; then
          echo "sys-update: run as your normal user (it sudos the rebuild itself)" >&2
          exit 1
        fi
        flake="''${NOMARCHY_PATH:-$HOME/.nomarchy}"
        echo "sys-update: updating flake inputs in $flake"
        nix flake update --flake "$flake"
        if command -v nixos-rebuild-snap >/dev/null 2>&1; then
          sudo nixos-rebuild-snap "$@"   # BTRFS snapshot first
        else
          sudo nixos-rebuild switch --flake "$flake#default" "$@"
        fi
      '')
      (pkgs.writeShellScriptBin "home-update" ''
        set -e
        exec home-manager switch --flake "''${NOMARCHY_PATH:-$HOME/.nomarchy}" "$@"
      '')

      git
      vim
      wget
      curl
      jq
      brightnessctl
      playerctl
      pamixer
      wl-clipboard
      grim
      slurp
    ] ++ lib.optional (cfg.snapper.enable && (config.fileSystems."/".fsType or "") == "btrfs")
      # Snapshot, then rebuild — rollback material for system changes
      # (theme changes don't need it; HM generations already roll back).
      (pkgs.writeShellScriptBin "nixos-rebuild-snap" ''
        if [ "$(id -u)" -ne 0 ]; then
          echo "This script must be run as root (use sudo)" >&2
          exit 1
        fi
        echo "Creating pre-rebuild snapshot..."
        ${pkgs.snapper}/bin/snapper -c root create \
          -d "Pre-rebuild $(date +'%Y-%m-%d %H:%M:%S')" \
          --cleanup-algorithm number
        echo "Rebuilding..."
        nixos-rebuild switch --flake /etc/nixos#default "$@"
      '');

    # Don't let boot entries fill the ESP over the years.
    boot.loader.systemd-boot.configurationLimit = lib.mkDefault 10;

    # Backlight udev rule (chgrp video + g+w on /sys/class/backlight) so
    # the desktop's swayosd brightness control works for video-group
    # users without root. Harmless baseline even if the OSD is disabled.
    services.udev.packages = [ pkgs.swayosd ];

    # ── Nix itself ───────────────────────────────────────────────────
    nix = {
      settings = {
        experimental-features = [ "nix-command" "flakes" ];
        auto-optimise-store = lib.mkDefault true;
      };
      gc = {
        automatic = lib.mkDefault true;
        dates = lib.mkDefault "weekly";
        options = lib.mkDefault "--delete-older-than 14d";
      };
    };
  };
}