#!/bin/sh
# 
# $Id: myplot,v 1.2 2010/01/10 05:06:54 grog Exp $
#
# Kludge page to generate plots
# These may need changing
STATION=Dereel
TABLE=observations
STARTDATE="2009-12-23"
ENDDATE="2009-12-24"
COMMON=/home/grog/src/weather/WH-1080/plots/plot-common.gnuplot
GRAPHFILE=/var/tmp/myplot.foo
OUTFILE=/home/grog/public_html/weather/myplot.png

# Generate some constants.  
# Calculate time zone offset from UTC
# Convert to seconds at UTC
NOW=`date +%Y%m%d%H%M`
UTC=`TZ=GMT date -j $NOW +%s`
# And in local time zone
LOCAL=`date -j $NOW +%s`
# The difference is the time zone offset.
TZOFFSET=`expr $UTC - $LOCAL`
# Number of seconds in a day
DAYSECS=86400
# 2000-1-1 0:0:0 UTC, the gnuplot epoch.  Or so it should be, but for
# some reason my plots come out offset by 2 hours.  Use GNUFUDGE until
# I find out why.
GNUFUDGE=7200
Y2K=`expr 946684800`
MY2K=`expr $Y2K + $TZOFFSET + $GNUFUDGE`
# End of constant generation

# Frob these values
STARTTIME=`date -j -f "%F %T" "$STARTDATE 0:0:0" +%s`
# Adjust to gnu epoch
GNUSTART=`expr $STARTTIME - $Y2K - $TZOFFSET - $GNUFUDGE`
# midnight on the end day
ENDTIME=`date -j -f "%F %T" "$ENDDATE 0:0:0" +%s`
GNUEND=`expr $ENDTIME - $Y2K - $TZOFFSET - $GNUFUDGE`
# echo  $ENDTIME - $Y2K - $TZOFFSET - $GNUFUDGE

# echo end $ENDTIME start $STARTTIME
DURATION=`expr $ENDTIME - $STARTTIME`
# echo DURATION $DURATION
# Decide how often to place the time ticks. 
if [ $DURATION -eq $DAYSECS ];  then # single day
    XTICS=10800 		# 3 hours
elif [ $DURATION -eq 172800 ]; then   # 2 days
    XTICS=21600 		# 6 hours
elif [ $DURATION -le 345600 ]; then # up to 4 days
    XTICS=43200 		# 6 hours
elif [ $DURATION -le 864000 ]; then # up to 10 days
    XTICS=86400 		# 6 hours
elif [ $DURATION -le 864000 ]; then # up to 10 days
    XTICS=86400 		# 1 day
elif [ $DURATION -le 2592000 ]; then # up to 30 days
    XTICS=172800 		# 2 days
else				# > 30 days
    XTICS=`expr $DURATION / 10`	# just hack it
fi

# echo DATE $STARTDATE ENDDATE $ENDDATE GNUEND $GNUEND DURATION $DURATION XTICS $XTICS

# **************************************************
# End of setup crap
# **************************************************

# Do the query
MY2KP1=`expr $Y2K + $TZOFFSET + $GNUFUDGE - $DAYSECS`
MY2KM1=`expr $Y2K + $TZOFFSET + $GNUFUDGE + $DAYSECS`
echo "SELECT unix_timestamp(timestamp(date, time))-$MY2K, outside_temp from $TABLE WHERE station_id = '$STATION' and date >='$STARTDATE' AND date <= '$STARTDATE' ORDER by date, time;" | \
  mysql weather > $GRAPHFILE.1
echo "SELECT unix_timestamp(timestamp(date, time))-$MY2KM1, outside_temp from $TABLE WHERE station_id = '$STATION' and date >='$ENDDATE' AND date <= '$ENDDATE' ORDER by date, time;" | \
  mysql weather > $GRAPHFILE.2

# And the plot

for GRAPHSIZE in "375,250" "1024, 720"; do
OUTFILE=/home/grog/public_html/weather/myplot.$GRAPHSIZE.png

( cat $COMMON
cat << EOF
	set title "Temperature comparison"
	set ylabel "Temperature (°C)"
plot "GRAPHFILE.1"  using 1:2  title "23 December"  with lines, \
     "GRAPHFILE.2"  using 1:2  title "24 December" with lines
EOF
) |  sed "s:MIDNIGHT:$GNUSTART:; s:ENDTIME:$GNUEND:; s:GRAPHFILE:$GRAPHFILE:g; s:SIZE:$GRAPHSIZE:; s:OUTFILE:$OUTFILE:; s:SMOOTHED: (smoothed):; s:SMOOTH:smooth bezier:; s:XTICS:$XTICS:" | \
  gnuplot
done