running vm that mostly works

platforms/home-manager/modules/nmasur/presets/programs/nix-index.nix

@@ -0,0 +1,40 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+
+let
+  cfg = config.nmasur.presets.programs.nix-index;
+in
+
+{
+
+  options.nmasur.presets.programs.nix-index.enable =
+    lib.mkEnableOption "nix-index caching for command line";
+
+  config = lib.mkIf cfg.enable {
+
+    # Provides "command-not-found" options
+    programs.nix-index = {
+      enable = true;
+      enableFishIntegration = true;
+    };
+
+    # Create nix-index if doesn't exist
+    home.activation.createNixIndex =
+      let
+        cacheDir = "${config.xdg.cacheHome}/nix-index";
+      in
+      lib.mkIf config.programs.nix-index.enable (
+        config.lib.dag.entryAfter [ "writeBoundary" ] ''
+          if [ ! -d ${cacheDir} ]; then
+              run ${pkgs.nix-index}/bin/nix-index -f ${pkgs.path}
+          fi
+        ''
+      );
+
+  };
+
+}