fix: init can be build from config

lib/modules/init.nix

@@ -1,6 +1,56 @@
-{pkgs, ...}: let
+{
+  pkgs,
+  callModule,
+  ...
+}: let
   inherit (builtins) isAttrs isPath isString readFile;
-  inherit (pkgs.lib) fix mkOption types;
+  inherit
+    (pkgs.lib)
+    fileContents
+    fix
+    mkOption
+    optionalAttrs
+    optionalString
+    types
+    ;
+
+  lua = callModule ../lua.nix {};
+
+  textOrContent = content:
+    if isPath content
+    then fileContents content
+    else content;
+
+  buildInit = {
+    init ? null,
+    postInit ? null,
+    config ? null,
+  }: let
+    initStr = optionalString (! isNull init) ''
+      (function()
+      ${textOrContent init}
+      end)();
+
+    '';
+
+    postInitContent = optionalAttrs (! isNull postInit) {
+      post_init = lua.lambda [] (textOrContent (lua.raw postInit));
+    };
+
+    slothCall = "require('sloth-flake').setup ${lua.renderLua {} postInitContent}";
+
+    configStr = optionalString (! isNull config) ''
+
+      (function()
+      ${textOrContent config}
+      end)()
+    '';
+  in ''
+    -- Generated by sloth-flake
+    ${initStr}
+    ${slothCall}
+    ${configStr}
+  '';
 in
   fix (self: {
     module = types.submodule {
@@ -46,6 +96,6 @@ in
       else if isPath init
       then readFile init
       else if isAttrs init
-      then "print('not implmented yet')"
+      then buildInit init
       else null;
   })