nix: modernize

nix/module.nix

@@ -1,13 +1,14 @@
-{
-  self,
+self: {
   config,
   pkgs,
   lib,
   ...
 }: let
-  inherit (lib) mkIf mkForce types;
+  inherit (lib.modules) mkIf mkForce;
   inherit (lib.options) mkOption mkEnableOption;
+  inherit (lib) types;
 
+  format = pkgs.formats.json {};
   cfg = config.services.batmon;
 in {
   options.services.batmon = {
@@ -20,25 +21,26 @@ in {
     };
 
     settings = mkOption {
-      description = "Settings for Batmon";
-      type = types.attrs;
+      type = format.type;
       default = {};
-      example = lib.literalExpression ''
-        {
-          batPaths = [
-            {
-              path = "/sys/class/power_supply/BAT0";
-              extraCommand = "notify-send 'State changed!'";
-            }
-          ];
-        }
-      '';
+      example = {
+        batPaths = [
+          {
+            path = "/sys/class/power_supply/BAT0";
+            extraCommand = "notify-send 'State changed!'";
+          }
+        ];
+      };
+
+      description = "Settings for BatmoSettings for Batmonn";
     };
   };
 
   config = mkIf cfg.enable {
     systemd.user.services."batmon" = {
       description = "Power Monitoring Service";
+      wants = ["power-profiles-daemon.service"];
+      wantedBy = ["default.target"];
       environment.PATH = mkForce "/run/wrappers/bin:${lib.makeBinPath cfg.package}";
       script = ''
         ${lib.getExe cfg.package} --config ${builtins.toJSON cfg.settings}
@@ -47,10 +49,8 @@ in {
       serviceConfig = {
         Type = "simple";
         Restart = "on-failure";
+        DynamicUser = true;
       };
-
-      wants = ["power-profiles-daemon.service"];
-      wantedBy = ["default.target"];
     };
   };
 }