# Opt-in services & integrations — off by default, one toggle each, enabled
# in system.nix (see the commented examples in the downstream template).
# These are system-side: their own `nomarchy.services.*` namespace, distinct
# from the distro's core `nomarchy.system.*` toggles. `username` (from
# specialArgs) is read lazily, only where a service needs it.
{ config, lib, pkgs, ... }@args:

let
  cfg = config.nomarchy.services;
in
{
  options.nomarchy.services = {
    tailscale.enable = lib.mkEnableOption ''
      Tailscale, the mesh VPN — ships the daemon; authenticate once with
      `sudo tailscale up`'';

    syncthing.enable = lib.mkEnableOption ''
      Syncthing continuous file sync, running as the login user — add
      folders and devices in the web UI at http://127.0.0.1:8384'';

    podman.enable = lib.mkEnableOption ''
      Podman for rootless containers, with `docker` aliased to it and DNS on
      the default network; the login user gets a subuid/subgid range'';

    flatpak.enable = lib.mkEnableOption ''
      Flatpak, with the Flathub remote added system-wide — install apps with
      `flatpak install flathub <app>`'';

    pika.enable = lib.mkEnableOption ''
      Pika Backup, a friendly GUI for scheduled Borg backups (the app;
      configure repositories and schedules inside it)'';

    steam.enable = lib.mkEnableOption ''
      Steam (Valve's game store/launcher) via programs.steam — which wires up
      the 32-bit graphics libraries, controller udev rules and Remote-Play
      firewall ports a bare package can't. Unfree'';

    libvirt.enable = lib.mkEnableOption ''
      libvirt/KVM virtualisation with the virt-manager GUI — runs the
      libvirtd daemon and adds the login user to the `libvirtd` group, so VMs
      can be managed without root'';

    obs.enable = lib.mkEnableOption ''
      OBS Studio for screen recording and streaming, plus a v4l2loopback
      virtual camera — so an OBS scene can be selected as a webcam in Zoom,
      Teams or a browser (screen capture itself already works over the
      desktop's PipeWire portal)'';
  };

  config = lib.mkMerge [
    (lib.mkIf cfg.tailscale.enable {
      services.tailscale.enable = true;
    })

    (lib.mkIf cfg.syncthing.enable {
      services.syncthing = {
        enable = true;
        user = args.username;
        # Manage folders/devices in the GUI; don't let the (empty) declarative
        # config wipe them on a rebuild.
        overrideDevices = false;
        overrideFolders = false;
        guiAddress = "127.0.0.1:8384";
      };
    })

    (lib.mkIf cfg.podman.enable {
      virtualisation.podman = {
        enable = true;
        dockerCompat = lib.mkDefault true; # `docker` → podman (off if you run real docker)
        defaultNetwork.settings.dns_enabled = true; # DNS for rootless containers
      };
      # Rootless podman needs a subuid/subgid range for the user.
      users.users.${args.username}.autoSubUidGidRange = lib.mkDefault true;
    })

    (lib.mkIf cfg.flatpak.enable {
      services.flatpak.enable = true;
      # Flatpak ships no remotes; add Flathub system-wide. Idempotent
      # (--if-not-exists), and it reads the .flatpakrepo over the network, so
      # it waits for connectivity and simply retries next boot if offline.
      systemd.services.nomarchy-flathub = {
        description = "Add the Flathub Flatpak remote";
        wantedBy = [ "multi-user.target" ];
        wants = [ "network-online.target" ];
        after = [ "network-online.target" ];
        path = [ pkgs.flatpak ];
        serviceConfig.Type = "oneshot";
        script = ''
          flatpak remote-add --system --if-not-exists flathub \
            https://dl.flathub.org/repo/flathub.flatpakrepo
        '';
      };
    })

    (lib.mkIf cfg.pika.enable {
      environment.systemPackages = [ pkgs.pika-backup ];
    })

    (lib.mkIf cfg.steam.enable {
      # The Steam package alone misses the system bits a game needs: the
      # 32-bit graphics stack, controller udev rules, Remote-Play ports.
      programs.steam.enable = true;
    })

    (lib.mkIf cfg.libvirt.enable {
      virtualisation.libvirtd.enable = true;
      programs.virt-manager.enable = true;
      # Group membership lets the user reach the system libvirtd socket
      # (manage VMs) without sudo. Merges with the user's other extraGroups.
      users.users.${args.username}.extraGroups = [ "libvirtd" ];
    })

    (lib.mkIf cfg.obs.enable {
      environment.systemPackages = [ pkgs.obs-studio ];
      # Virtual camera: OBS streams a scene into a v4l2 loopback device that
      # Zoom/Teams/browsers then pick up as a webcam. exclusive_caps=1 is the
      # bit that makes those apps actually list the device.
      boot.extraModulePackages = [ config.boot.kernelPackages.v4l2loopback ];
      boot.kernelModules = [ "v4l2loopback" ];
      boot.extraModprobeConfig = ''
        options v4l2loopback devices=1 video_nr=10 card_label="OBS Virtual Camera" exclusive_caps=1
      '';
    })
  ];
}