#!/bin/bash

# How long to display countdown dialog
cntDown=60

# Dialog timeout
dlgTimeout=2

# Minimum battery level to reach before forcing hibernation
minBattLvl=20

# Replacement text for OK dialog box button
btntext="Proceed"

while [[ $cntDown -gt 0 ]] ; do
   ioreg -w0 -l | grep ExternalChargeCapable | grep -q Yes
   if [[ $? -ne 0 ]] ; then
      max="`ioreg -w0 -l | grep MaxCapacity | cut -d= -f 2`"
      avail="`ioreg -w0 -l | grep CurrentCapacity | cut -d= -f 2`"
      pct=$(($avail*100/$max))
   else
      exit 0   # We are charging, nothing to do....
   fi

   userResp="`/usr/bin/osascript 2>&1 <<-EOF
    tell application "System Events"
        activate
        display dialog \
        "Battery below min safe level of ${minBattLvl}%" \
        & "\\n\\nForcing hibernation in: ${cntDown} seconds." \
        as text buttons {"Cancel","$btntext"} \
        default button "$btntext" \
        with icon caution \
        with title "WARNING: Battery Monitor" \
        giving up after $dlgTimeout
    end tell
EOF`"

   echo $userResp | grep -q "User canceled"
   abort=$?
   [[ $abort -eq 0 ]] && exit 0

   echo $userResp | grep -q $btntext
   proceed=$?
   [[ $proceed -eq 0 ]] && let cntDown=0

   let cntDown-=2
done

# Log it in syslog
logger "BatteryMonitor: Battery level below ${minBattLvl}%. Forcing hibernation..."

# Activate sleep/hibernation`
pmset sleepnow