# NixOS module: runs a Sausage world as a service (see README, "As a service").
# Create the world once: sudo -u sausage nix run git+https://gitea.surma.technology/surma/sausage -- init /var/lib/sausage/world
{ config, lib, pkgs, ... }:
let cfg = config.services.sausage; in
{
  options.services.sausage = {
    enable = lib.mkEnableOption "the Sausage world";
    world = lib.mkOption { type = lib.types.str; default = "/var/lib/sausage/world"; };
    flake = lib.mkOption {
      type = lib.types.str;
      default = "git+https://gitea.surma.technology/surma/sausage";
    };
  };
  config = lib.mkIf cfg.enable {
    users.users.sausage = { isSystemUser = true; group = "sausage"; home = "/var/lib/sausage"; createHome = true; };
    users.groups.sausage = { };
    systemd.services.sausage = {
      description = "Sausage world";
      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];
      path = [ pkgs.nix pkgs.git ];
      serviceConfig = {
        User = "sausage";
        WorkingDirectory = "/var/lib/sausage";
        ExecStart = "${pkgs.nix}/bin/nix run ${cfg.flake}#loop -- --headless ${cfg.world}";
        Restart = "on-failure";
        RestartSec = 5;
        TimeoutStopSec = 30;
      };
    };
  };
}