#!/bin/sh

#
# Extract hourly average temperature readings from an RRD file
# and draw them in a colour graph of days x hours
#
# Usage: # thermosquare.sh [ <month> [ <year> ] ] 
#
# So if we run it with no arguments we update the current month
#
# Chris Gillings 2007
#

MONTH=`date '+%m'`
YEAR=`date '+%Y'`
CYEAR=$YEAR

if [ "z$1" != "z" ]; then
   MONTH=$1
fi
if [ "z$2" != "z" ]; then
   YEAR=$2
fi

# If I was fussed I'd add in a Leap Year calculation here
case $MONTH in
    (04|06|09|11) DAYS=30;;
    (02) DAYS=28;;
    (*) DAYS=31;;
esac

# we have yearly backups of the RRD file
RRDFILE=airtemp.rrd.0.$YEAR

# if it's this year we take a fresh copy of the active file
if [ $YEAR == $CYEAR ]; then
   cp /var/lib/rrd/sys/airtemp.rrd.0 airtemp.rrd.0.$YEAR
fi

# extract hourly stats for this month into a plain text file
rrdtool xport --start "00:00 ${YEAR}${MONTH}01" --end "23:00 ${YEAR}${MONTH}${DAYS}" DEF:xx=${RRDFILE}:t:AVERAGE:step=3600 XPORT:xx:"Temp" | grep "<v>" | sed 's#^.*<v>##g' | sed 's#</v.*##g' > ${YEAR}${MONTH}.vals

# (re)generate the graph for this month
php thermosquare.php month=${YEAR}${MONTH}

# that's all