plugins/lsp/nixd: refactor

plugins/lsp/language-servers/nixd-settings.nix

@@ -0,0 +1,46 @@
+{ lib, helpers }:
+# Options:
+#  - https://github.com/nix-community/nixd/blob/main/nixd/docs/configuration.md
+#  - https://github.com/nix-community/nixd/blob/main/nixd/include/nixd/Controller/Configuration.h
+with lib;
+{
+  formatting = {
+    command = helpers.defaultNullOpts.mkListOf types.str ''[ "nixpkgs-fmt" ]'' ''
+      Which command you would like to do formatting.
+      Explicitly set to `["nixpkgs-fmt"]` will automatically add `pkgs.nixpkgs-fmt` to the nixvim
+      environment.
+    '';
+  };
+
+  options =
+    let
+      provider = types.submodule {
+        options = {
+          expr = mkOption {
+            type = types.str;
+            description = "Expression to eval. Select this attrset as eval .options";
+          };
+        };
+      };
+    in
+    helpers.mkNullOrOption (with helpers.nixvimTypes; attrsOf (maybeRaw provider)) ''
+      Tell the language server your desired option set, for completion.
+      This is lazily evaluated.
+    '';
+
+  nixpkgs =
+    let
+      provider = types.submodule {
+        options = {
+          expr = mkOption {
+            type = types.str;
+            description = "Expression to eval. Treat it as `import <nixpkgs> { }`";
+          };
+        };
+      };
+    in
+    helpers.mkNullOrOption (helpers.nixvimTypes.maybeRaw provider) ''
+      This expression will be interpreted as "nixpkgs" toplevel
+      Nixd provides package, lib completion/information from it.
+    '';
+}