{ self, ... }:
let
  inherit
    (self.inputs)
    nixpkgs
    home-manager
    agenix
    nur
    colmena
    flake-registry
    nixos-hardware
    srvos
    disko
    ;
  nixosSystem = nixpkgs.lib.makeOverridable nixpkgs.lib.nixosSystem;

  colmenaModules = [
    colmena.nixosModules.deploymentOptions
  ];

  commonModules = [
    {
      _module.args.self = self;
      _module.args.inputs = self.inputs;
      srvos.flake = self;
    }
    # only include admins here for monitoring/backup infrastructure
    ./modules/users/admins.nix
    ./modules/packages.nix
    ./modules/nix-daemon.nix
    ./modules/tor-ssh.nix
    ./modules/hosts.nix
    ./modules/network.nix
    ./modules/zsh.nix
    # FIXME: ./modules/buildbot — whenever you are ready.


    disko.nixosModules.disko
    srvos.nixosModules.server

    srvos.nixosModules.mixins-trusted-nix-caches
    srvos.nixosModules.mixins-terminfo

    # srvos.nixosModules.mixins-telegraf
    # srvos.nixosModules.mixins-terminfo

    agenix.nixosModules.default
    ({ pkgs
     , config
     , lib
     , ...
     }:
      let
        sopsFile = ./. + "/hosts/${config.networking.hostName}.yml";
      in
      {
        nix.nixPath = [
          "home-manager=${home-manager}"
          "nixpkgs=${pkgs.path}"
          "nur=${nur}"
        ];
        # TODO: share nixpkgs for each machine to speed up local evaluation.
        #nixpkgs.pkgs = self.inputs.nixpkgs.legacyPackages.${system};

        #users.withSops = builtins.pathExists sopsFile;
        #sops.secrets = lib.mkIf (config.users.withSops) {
        #  root-password-hash.neededForUsers = true;
        #};
        # sops.defaultSopsFile = lib.mkIf (builtins.pathExists sopsFile) sopsFile;

        nix.extraOptions = ''
          flake-registry = ${flake-registry}/flake-registry.json
          builders-use-substitutes = true
        '';

        nix.registry = {
          home-manager.flake = home-manager;
          nixpkgs.flake = nixpkgs;
          nur.flake = nur;
        };
        time.timeZone = "UTC";

        environment.systemPackages = [
          pkgs.kitty.terminfo
        ];
      })
  ];
in
{
  flake.nixosConfigurations = {
    epyc = nixosSystem {
      system = "x86_64-linux";
      modules =
        commonModules
        ++ colmenaModules
        ++ [
          ./hosts/epyc.nix
        ];
    };
  };

  flake.colmena = {
    meta.nixpkgs = import nixpkgs {
      system = "x86_64-linux";
    };
    epyc = {
      imports =
        commonModules
        ++ [
          ./hosts/epyc.nix
        ];
    };
  };
}