add (lib): make the function to create nixos system

lib/config.nix

@@ -0,0 +1,88 @@
+{
+  inputs,
+  nixpkgs,
+  nixpkgs-old,
+  nixpkgs-latest,
+}:
+deviceName:
+{
+  hostName,
+  userName,
+  additionalOverlays ? [ ],
+  systemArch ? builtins.currentSystem,
+}:
+let
+  inherit (nixpkgs) lib;
+
+  customFunctions = import ./utils.nix { inherit lib; };
+
+  baseOverlays =
+    import ../overlays {
+      inherit
+        systemArch
+        nixpkgs-old
+        nixpkgs-latest
+        packagesConfig
+        ;
+    }
+    |> builtins.attrValues;
+  overlays = baseOverlays ++ additionalOverlays;
+
+  DeviceConfig = ../devices/${deviceName};
+  HostConfig = ../users/${hostName}/host;
+  HomeConfig = ../users/${userName}/home;
+
+  userData = import ../users/${userName}/data.nix {
+    inherit
+      deviceName
+      hostName
+      userName
+      systemArch
+      ;
+  };
+
+  userPackagesConfig = import ../users/${hostName}/packages-config.nix { inherit lib; };
+
+  additionalArgs = { inherit inputs customFunctions userData; };
+
+  sops = {
+    defaultSopsFormat = "yaml";
+    defaultSopsFile = ../secrets/main.yaml;
+    age.keyFile = "${userData.paths.sopsKeyFile}";
+  };
+in
+lib.nixosSystem {
+  system = systemArch;
+  specialArgs = additionalArgs;
+
+  modules = [
+    DeviceConfig
+    HostConfig
+
+    {
+      nixpkgs = {
+        inherit overlays;
+        config = userPackagesConfig;
+      };
+    }
+
+    inputs.home-manager.nixosModules.home-manager
+    {
+      home-manager = {
+        users.${userName} = import HomeConfig;
+        useGlobalPkgs = true;
+        useUserPackages = true;
+        extraSpecialArgs = additionalArgs;
+        sharedModules = [
+          inputs.sops-nix.homeManagerModules.sops
+        ];
+      };
+    }
+
+    inputs.sops-nix.nixosModules.sops
+    {
+      inherit sops;
+      home-manager.users.${userName} = { inherit sops; };
+    }
+  ];
+}