#!/bin/sh

if [ $# -ne 2 ]; then
	echo 'usage: tlapse.r1 <number-of-images> <seconds-between-images>'
	exit 0
fi

function tidy_exit ()
{
    echo 
    exit 0
}
trap tidy_exit SIGINT
trap tidy_exit SIGHUP

brem=$(grep /proc/acpi/battery/BAT0/state -e remaining | sed -e 's/^.* \([0-9]\+\) .*$/\1/')
echo $(date), PC Battery = $brem

modprobe ftdi_sio
stty -F /dev/ttyUSB0 110 cstopb

i=1
n=$1
t=$2
b=$(date +%s)
st=0
while [ $i -le $n ]; do
    echo -e '\000\000\000\000\000\000\000\000\000\000' > /dev/ttyUSB0
    brem=$(grep /proc/acpi/battery/BAT0/state -e remaining | sed -e 's/^.* \([0-9]\+\) .*$/\1/')
    a=$(date +%s)
    if [ $st -eq 0 ]; then
	st=$a
	oldbrem=$brem
	echo -e -n \\r$i - $(date), PC Battery = $brem
    else
	brate=$[($oldbrem - $brem) * 60 / ($a - $st)]
	if [ $brate -gt 0 ]; then
	    ml=$[$brem / $brate]
	fi
	echo -e -n \\r$i - $(date), PC Battery = $brem "($brate/minute, $ml minutes left)"
    fi
    i=$[$i + 1]
    if [ $t -gt $[$a - $b] -a $i -le $n ]; then
	echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 
	sleep $[$t - ($a - $b)]
	echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 
    fi
    b=$(date +%s)
done
tidy_exit