let target-version = "21.05";

in {
  description = "Fudo Host Configuration";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-${target-version}";
    home-manager.url =
      "github:nix-community/home-manager/release-${target-version}";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { nixpkgs, home-manager, ... }:
    let
      lib = nixpkgs.lib;
      is-nix-file = filename: type: (builtins.match ".+.nix$" filename) != null;
      is-regular-file = filename: type: type == "regular" || type == "link";
      hostname-from-file = filename:
        builtins.replaceStrings [ ".nix" ] [ "" ] filename;
      hosts = map hostname-from-file (lib.attrNames (lib.filterAttrs is-nix-file
        (lib.filterAttrs is-regular-file (builtins.readDir ./config/hosts))));

      pkgs = import nixpkgs { };

    in {
      nixConfigurations = lib.mapAttrs (hostname: hostOpts:
        lib.nixosSystem {
          system = hostOpts.architecture;
          modules = [
            (import ./initialize.nix {
              hostname = hostname;
              home-manager-package = home-manager;
              pkgs = pkgs;
              include-secrets = true;
            })
          ];
        }) hosts;
    };
}