modules/nilla: flake compatibility module

flake.nix

@@ -1,34 +1,5 @@
 {
-  outputs =
+  outputs = inputs: (import ./nilla.nix { inherit inputs; }).flake;
-    inputs:
-    let
-      nilla = import ./nilla.nix { inherit inputs; };
-      systems = [
-        "x86_64-linux"
-        "aarch64-linux"
-        "aarch64-darwin"
-      ];
-      # NOTE: Assumes every package is available for every system.
-      #       For now let's say this is always the case.
-      transpose =
-        attrs:
-        let
-          inherit (inputs.nixpkgs) lib;
-          mappedForSystem = system: builtins.mapAttrs (_: pkg: pkg.result.${system}) attrs;
-        in
-        lib.genAttrs systems mappedForSystem;
-    in
-    {
-      inherit (nilla) nixosModules;
-      inherit (nilla) darwinModules;
-      inherit (nilla) homeModules;
-      inherit (nilla) nixosConfigurations;
-      inherit (nilla) darwinConfigurations;
-      inherit (nilla) homeConfigurations;
-      devShells = transpose nilla.shells;
-      packages = transpose nilla.packages;
-      formatter = nilla.packages.formatter.result;
-    };
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixpkgs-unstable";
@@ -128,26 +99,4 @@
       flake = false;
     };
   };
-
-  /*
-    TODO: Uncomment once (if ever?) nixConfig makes sense in flakes
-    nixConfig = {
-      extra-substituters = [
-        "https://hyprland.cachix.org"
-        "https://cache.garnix.io"
-        "https://nix-community.cachix.org"
-        "https://hercules-ci.cachix.org"
-        "https://nrabulinski.cachix.org"
-        "https://cache.nrab.lol"
-      ];
-      extra-trusted-public-keys = [
-        "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
-        "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
-        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-        "hercules-ci.cachix.org-1:ZZeDl9Va+xe9j+KqdzoBZMFJHVQ42Uu/c/1/KMC5Lw0="
-        "nrabulinski.cachix.org-1:Q5FD7+1c68uH74CQK66UWNzxhanZW8xcg1LFXxGK8ic="
-        "cache.nrab.lol-1:CJl1TouOyuJ1Xh4tZSXLwm3Upt06HzUNZmeyuEB9EZg="
-      ];
-    };
-  */
 }

modules/nilla/default.nix

@@ -4,5 +4,6 @@
     ./services.nix
     ./configurations.nix
     ./modules.nix
+    ./flake.nix
   ];
 }

modules/nilla/flake.nix

@@ -0,0 +1,31 @@
+{ lib, config }:
+let
+  systems = [
+    "x86_64-linux"
+    "aarch64-linux"
+    "aarch64-darwin"
+  ];
+  transpose =
+    attrs: lib.attrs.generate systems (system: builtins.mapAttrs (_: pkg: pkg.result.${system}) attrs);
+in
+{
+  options.flake = lib.options.create {
+    type = lib.types.attrs.of lib.types.raw;
+  };
+
+  config.flake = {
+    inherit (config)
+      nixosModules
+      darwinModules
+      homeModules
+      nixosConfigurations
+      darwinConfigurations
+      homeConfigurations
+      ;
+
+    devShells = transpose config.shells;
+    packages = transpose config.packages;
+
+    formatter = config.packages.formatter.result;
+  };
+}