Add hinernation on low battery feature

home/battery/default.nix

@@ -1,11 +1,21 @@
 { config, pkgs, ... }:
 
 let
-  batteryNotify = pkgs.writeShellScript "battery-notify" ''
+  battery = pkgs.writeShellScript "battery" ''
     BAT="/sys/class/power_supply/BAT1"
     LEVEL=$(cat "$BAT/capacity")
     STATUS=$(cat "$BAT/status")
 
+    has_notifications() {
+      ${pkgs.dbus}/bin/busctl --user status org.freedesktop.Notifications >/dev/null 2>&1
+    }
+
+    if [ "$STATUS" = "Discharging" ] && [ "$LEVEL" -lt 3 ]; then
+      ${pkgs.systemd}/bin/systemctl hibernate
+      exit 0
+    fi
+
+    if has_notifications; then
       if [ "$STATUS" = "Discharging" ] && [ "$LEVEL" -lt 20 ]; then
         ${pkgs.dunst}/bin/dunstify \
           -r 9991 \
@@ -17,30 +27,29 @@ let
         ${pkgs.dunst}/bin/dunstify \
           -C 9991 2>/dev/null || true
       fi
+    fi
   '';
 in
 {
-  systemd.user.services.battery-notify = {
+  systemd.user.services.battery = {
     Unit = {
-      Description = "Low battery notification";
-      After = [ "dunst.service" ];
-      Requires = [ "dunst.service" ];
+      Description = "Battery management";
     };
 
     Service = {
       Type = "oneshot";
-      ExecStart = batteryNotify;
+      ExecStart = battery;
     };
   };
 
-  systemd.user.timers.battery-notify = {
+  systemd.user.timers.battery = {
     Unit = {
-      Description = "Check battery level every 20 seconds";
+      Description = "Check battery level every 15 seconds";
     };
 
     Timer = {
-      OnBootSec = "20s";
-      OnUnitActiveSec = "20s";
+      OnBootSec = "15s";
+      OnUnitActiveSec = "15s";
     };
 
     Install = {