nix: module improvements

module.nix

@@ -14,6 +14,12 @@ in {
         The package implementing disconic
       '';
     };
+    user = mkOption {
+      type = types.str;
+      default = "yrmos";
+      description = "Service user that will run the daemon.";
+    };
+
     subsonicUrl = mkOption {
       type = types.str;
       description = "Subsonic library base API URL";
@@ -30,6 +36,10 @@ in {
       type = types.path;
       description = "File path containing discord token";
     };
+    discordGuild = mkOption {
+      type = types.str;
+      description = "Your server's guild ID, to auto-register commands";
+    };
     extraArgs = mkOption {
       type = types.listOf types.str;
       default = [ ];
@@ -41,13 +51,27 @@ in {
     systemd.services.disconic = {
       description = "Disconic, a Discord Subsonic Bot";
       wantedBy = [ "multi-user.target" ];
-      serviceConfig.ExecStart = lib.escapeShellArgs ([
-        (lib.getExe cfg.package)
-        "--subsonic-url=${cfg.subsonicUrl}"
-        "--subsonic-user=${cfg.subsonicUser}"
-        "--subsonic-password=$(cat ${cfg.subsonicPasswordFile})"
-        "--discord-token=$(cat ${cfg.discordTokenFile}"
-      ] ++ cfg.extraArgs);
+      serviceConfig = {
+        Restart = "always";
+        User = cfg.user;
+        ExecStart = lib.escapeShellArgs ([
+          (lib.getExe cfg.package)
+          "--subsonic-url=${cfg.subsonicUrl}"
+          "--subsonic-user=${cfg.subsonicUser}"
+          "--subsonic-password=$(cat ${cfg.subsonicPasswordFile})"
+          "--discord-token=$(cat ${cfg.discordTokenFile})"
+          "--discord-guild=${cfg.discordGuild}"
+        ] ++ cfg.extraArgs);
+      };
+    };
+
+    users = {
+      users.${cfg.user} = {
+        description = "disconic service user";
+        isSystemUser = true;
+        group = cfg.user;
+      };
+      groups.${cfg.user} = { };
     };
   };
 }