#!/bin/bash
#
# Script for polling the battery state for systems where the battery
# doesn't send acpi reports and has no alarm support. Unfortunately
# laptop-mode-tools auto-hibernate module depends on that to work
# properly.
# 
# Script was found on gentoo-wiki.com with no license information. 
# Assuming it's public domain it is included here as such, WITHOUT ANY
# WARRANTY.

LIMIT="200" ## Hibernate if battery level drops below this (in mAh/mWh)
SLEEP="60"  ## Seconds between each battery level check
BAT="BAT0"  ## Part of path: /proc/acpi/battery/BAT
HIBERNATE="/usr/sbin/pm-hibernate" ## command used to hibernate

while [ true ]; do
  if [ -e "/proc/acpi/battery/$BAT/state" ]; then
     PRESENT=$(/bin/sed -ne "/present:/{s/^present:[ ]*\([a-z]*\)$/\1/p;q}" /proc/acpi/battery/$BAT/state)
     #echo $PRESENT
     if [ "$PRESENT" = "yes" ]; then
        STATE=$(/bin/sed -ne "/charging state:/{s/^charging state:[ ]*\([a-zA-Z]*\)$/\1/p;q}" /proc/acpi/battery/$BAT/state)
        BATTERY=$(/bin/sed -ne "/remaining capacity:/{s/^remaining capacity:[ ]*\([0-9]*\) m[WA]h$/\1/p;q}" /proc/acpi/battery/$BAT/state)
        #echo $BATTERY
        #echo $STATE
        if [ "$BATTERY" -lt "$LIMIT" ] && [ "$STATE" = "discharging" ]; then
           ## Comment out the following line if you don't
           ## want to log the event to system log:
           logger "Battery at ${BATTERY} mWh. Suspending the system to disk."
           #echo "Battery at ${BATTERY} mWh. Suspending the system to disk."

           ## Hibernate:
           exec "$HIBERNATE"
       fi
     fi
  fi

  sleep ${SLEEP}s
done