nixos/flake.nix

{
  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
    lib = nixpkgs.lib;
    fn = import ./fn.nix { inherit lib; };
    mappedFormatter = builtins.mapAttrs (arch: packages: packages.default) alejandra.packages;
    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 (name: lib.strings.hasSuffix ".nix" name) (fn.lst { p = machinePath; b = true; });
      in nixpkgs.lib.nixosSystem {
        inherit system;
        specialArgs = attrs // { fn = fn; };
        modules = [
          (toString ./options/machine.nix)
          sops-nix.nixosModules.sops
        ] ++ machineFiles
        ++ configFiles
        ++ pkgsFiles
        ++ serviceFiles;
      };
    };
  in {
    formatter = mappedFormatter;
    nixosConfigurations = lib.listToAttrs (map nixosSystemFor machineList);
  };
}