#!/bin/sh
# This script exits with status 0 when the computer is on AC power (or no AC
# power supply found), 1 otherwise (i.e. running on battery).
set -u

verbose=false
[ "${1:-}" = '-v' ] && verbose=true

# If we do not have any power supplies, assume we are on AC.
rc=0

# Iterate through power supplies sysfs knows about.
for ps in /sys/class/power_supply/*; do
	[ -r $ps/online ] || continue
	# We know we have an AC adaptor, our default return changes to failed.
	rc=1

	if [ "$(cat $ps/online)" -eq 1 ]; then
		rc=0
		break
	fi
done

$verbose && echo $rc
exit $rc