#!/bin/sh
# Suspend the system, but only if running on battery. Used as the
# swayidle `timeout` action so idle suspends save battery without ever
# firing while the laptop is plugged in.
#
# Manual suspends (sway keybinds, `systemctl suspend` over SSH) bypass
# this script and always work -- explicit user intent wins.
set -eu

for ac in /sys/class/power_supply/AC*/online \
  /sys/class/power_supply/ADP*/online; do
  [ -r "$ac" ] || continue
  if [ "$(cat "$ac")" = "1" ]; then
    exit 0
  fi
done

exec systemctl suspend