let
  inherit (builtins) filter mapAttrs;

  # https://github.com/andir/npins?tab=readme-ov-file#using-the-nixpkgs-fetchers
  src = import ./npins;
  pkgs = import src.nixpkgs { };
  sources = mapAttrs (k: v: v { inherit pkgs; }) src;

  inherit (pkgs) lib;
  inherit (lib.filesystem) listFilesRecursive;
  inherit (lib.strings) hasSuffix;

  mkSystem =
    system: hostname:
    import (src.nixpkgs + "/nixos/lib/eval-config.nix") {
      specialArgs = {
        inherit sources;
        self = ./.;
      };
      modules = [
        # This is used to pre-emptively set the hostPlatform for nixpkgs.
        # Also, we set the system hostname here.
        { networking.hostName = hostname; }
        ./hosts/common.nix
        ./hosts/${hostname}
      ]
      ++ ((listFilesRecursive ./modules) |> filter (hasSuffix ".mod.nix"));
    };
in
{
  temperance = mkSystem "x86_64-linux" "temperance";
  hermit = mkSystem "x86_64-linux" "hermit";
  tower = mkSystem "aarch64-linux" "tower";
}