{ inputs, ... }:
let
  inherit (inputs) nixpkgs;
  inherit (nixpkgs) lib;
in {
  configurations =
    lib.mapAttrs
    (dir: _:
      let
        inherit (import ./machines/${dir}/sysidentity.nix) sysidentity;

        package-modules =
          let
            listget = attrname:
              if sysidentity ? ${attrname}
              then map
                    (v: ./modules + ("/" + v + (if lib.hasSuffix ".nix" v then "" else ".nix")))
                    sysidentity.${attrname}
              else [];
            havelist = listget "have";
            droplist = listget "drop";
            modulelist =
              if (sysidentity ? defaultempty) && sysidentity.defaultempty
              then []
              else lib.mapAttrsToList
                    (name: _: ./modules + ("/" + name))
                    (lib.filterAttrs (_: type: type == "regular") (builtins.readDir ./modules));
          in
            lib.subtractLists droplist (havelist ++ modulelist);

        inputs-overlays =
          lib.mapAttrs
          (_: nixpkgs-special:
            nixpkgs-special.legacyPackages.${sysidentity.arch})
          (lib.filterAttrs
            (name: _:
              lib.hasPrefix "nixpkgs-" name)
            inputs);

        custom-packages-overlays =
          lib.mapAttrs
          (name: _:
            nixpkgs.legacyPackages.${sysidentity.arch}.callPackage ./packages/${name} { })
          (lib.filterAttrs (_: type: type == "directory") (builtins.readDir ./packages));

        package-overlays =
          lib.mapAttrsToList
          (name: _: (import ./overlays/${name}))
          (builtins.readDir ./overlays);

      in
      lib.nixosSystem {
        system = sysidentity.arch;
        modules = [
          ./machines/${dir}/hardware-configuration.nix
          ./configuration.nix
          ({ ... }: {
            networking.hostName = sysidentity.name;
            nixpkgs.overlays = [ (_: _: inputs-overlays) (_: _: custom-packages-overlays) ] ++ package-overlays;
          })
        ]
        ++ (if lib.pathIsRegularFile ./machines/${dir}/configuration.nix
            then [ ./machines/${dir}/configuration.nix ]
            else [])
        ++ package-modules;
      })
    (lib.filterAttrs (_: type: type == "directory") (builtins.readDir ./machines));
}