feat: import configuration based on convention

flake-module.nix

@@ -6,7 +6,9 @@
 }: let
   cfg = config.nix-machine;
 
-  configurations = map (x: x.value) (lib.attrsets.attrsToList cfg.configurations);
+  parseConfig = import ./lib/parse-config.nix {inherit lib;};
+
+  configurations = map (x: x.value) (lib.attrsets.attrsToList (parseConfig cfg.configurations));
 
   sharedOptions = lib.catAttrs "options" configurations;
   nixDarwinConfigurations = lib.catAttrs "nixDarwin" configurations;
@@ -30,6 +32,14 @@
       type = lib.types.deferredModule;
       default = {};
     };
+    path = lib.mkOption {
+      type = lib.types.nullOr lib.types.path;
+      default = null;
+    };
+    scheme = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+    };
   };
 in {
   options.nix-machine.configurations = lib.mkOption {

lib/parse-config.nix

@@ -0,0 +1,35 @@
+{lib, ...}: let
+  enumerateModules = basePath: fileName: let
+    inherit (builtins) readDir;
+    inherit (lib) attrNames filter filterAttrs pathExists foldl';
+    inherit (lib.trivial) pipe;
+
+    packagePaths = path: attrNames (filterAttrs (_: type: type == "directory") (readDir path));
+    modulesInPackage = package: [package "${fileName}.nix"];
+    renderPath = foldl' (path: elem: path + "/${elem}");
+
+    modules = pipe (packagePaths basePath) [
+      (map modulesInPackage)
+      (map (renderPath basePath))
+      (filter pathExists)
+    ];
+  in
+    {...}: {
+      imports = modules;
+    };
+
+  importConfig = path: let
+    createModule = enumerateModules path;
+  in {
+    options = createModule "options";
+    nixDarwin = createModule "darwin-module";
+    homeManager = createModule "hm-module";
+  };
+
+  # If a path is specified,
+  main = configuration:
+    if configuration.path != null && configuration.scheme == "flat"
+    then importConfig configuration.path
+    else configuration;
+in
+  configurations: builtins.mapAttrs (c: v: main v) configurations