nix-init: add module (#6864)

Co-authored-by: uncenter <47499684+uncenter@users.noreply.github.com>

modules/programs/nix-init.nix

@@ -0,0 +1,60 @@
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+let
+  tomlFormat = pkgs.formats.toml { };
+  cfg = config.programs.nix-init;
+in
+{
+  meta.maintainers = [ lib.maintainers.awwpotato ];
+
+  options.programs.nix-init = {
+    enable = lib.mkEnableOption "nix-init";
+    package = lib.mkPackageOption pkgs "nix-init" { nullable = true; };
+    settings = lib.mkOption {
+      type = tomlFormat.type;
+      default = { };
+      example = lib.literalExpression ''
+        {
+          maintainers = [
+            "figsoda"
+          ];
+          nixpkgs = "<nixpkgs>";
+          commit = true;
+          access-tokens = {
+            github.com = "ghp_blahblahblah...";
+            gitlab.com = {
+              command = [
+                "secret-tool"
+                "or"
+                "whatever"
+                "you"
+                "use"
+              ];
+            };
+            gitlab.gnome.org = {
+              file = "/path/to/api/token";
+            };
+          };
+        }
+      '';
+      description = ''
+        Configuration written to
+        {file}`$XDG_CONFIG_HOME/nix-init/config.toml`.
+        See <https://github.com/nix-community/nix-init#configuration> for the full list
+        of options.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    home.packages = lib.mkIf (cfg.package != null) [ cfg.package ];
+
+    xdg.configFile."nix-init/config.toml" = lib.mkIf (cfg.settings != { }) {
+      source = tomlFormat.generate "config.toml" cfg.settings;
+    };
+  };
+}