{
  description = "NixOS Configuration";
  inputs = rec {
    nixpkgs-git.url = "github:/NixOS/nixpkgs";
    nixpkgs-stable.url = "github:/NixOS/nixpkgs/nixos-22.11";
    nixpkgs-unstable.url = "github:/NixOS/nixpkgs/nixos-unstable";
    nixpkgs.url = "github:/NixOS/nixpkgs/nixos-unstable";
    alejandra = {
      url = "github:kamadorueda/alejandra/3.0.0";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    mailserver.url = "gitlab:/simple-nixos-mailserver/nixos-mailserver";
    sops-nix = {
      url = "github:Mic92/sops-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs = {
    self,
    nixpkgs,
    alejandra,
    mailserver,
    sops-nix,
    ...
  } @ attrs: let
    inherit (nixpkgs) lib;
    fn = import ./fn.nix {inherit lib;};
    mappedFormatter = builtins.mapAttrs (arch: packages: packages.default) alejandra.packages;
    mappedApps =
      builtins.mapAttrs (_arch: packages: {
        "lint" = {
          type = "app";
          program = "${packages.statix}/bin/statix";
        };
      })
      nixpkgs.legacyPackages;
    system = "x86_64-linux";
    machineList = fn.lst {
      p = toString ./machines;
      t = "directory";
      b = false;
    };
    configFiles = fn.lst {
      p = toString ./config;
      b = true;
    };
    pkgsFiles = fn.lst {
      p = toString ./pkgs;
      b = true;
    };
    serviceFiles = fn.lst {
      p = toString ./services;
      b = true;
    };
    nixosSystemFor = machine: {
      name = machine;
      value = let
        machinePath = lib.concatStringsSep "/" [(toString ./.) "machines" machine];
        machineFiles = lib.filter (lib.strings.hasSuffix ".nix") (fn.lst {
          p = machinePath;
          b = true;
        });
      in
        nixpkgs.lib.nixosSystem {
          inherit system;
          specialArgs =
            attrs
            // {
              inherit system;
              inherit fn;
            };
          modules =
            [
              (toString ./options/machine.nix)
              sops-nix.nixosModules.sops
            ]
            ++ machineFiles
            ++ configFiles
            ++ pkgsFiles
            ++ serviceFiles;
        };
    };
  in {
    apps = mappedApps;
    formatter = mappedFormatter;
    nixosConfigurations = lib.listToAttrs (map nixosSystemFor machineList);
  };
}