#!/bin/sh
#
# Written by Craig Huff
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#

#
## Define a constant for the maximum amount of time difference, in seconds,
## that we want to allow between the current time and the time that zap2it
## suggested for the next database update. (5 seconds)
margin=5

#
## Is there already an at-job to take care of this?
#
grep mythfilldatabase /var/spool/at/* >& /dev/null
if [ "$?" != "0" ]; then	#no at-job (yet)

#
## Is it more or less time to get an update from zap2it?
#
## First, get the time zap2it suggested as the next update time from the log
## and convert it into the number of seconds since the "epoch"
  nexttime=`cat /var/log/mythtv/mythfilldatabase.log.1 /var/log/mythtv/mythfilldatabase.log | grep NextSuggestedTime | tail -1 | awk '{print $NF}' | sed -e 's/T/ /'`
  epochtime=`date -u -d "${nexttime}" +%s`

#
## Next, get the current time in seconds since the "epoch"
  thistime=`date +%s`

#
## Subtract the larger time from the smaller to get a positive difference
  if [ ${epochtime} -gt ${thistime} ]; then
    difftime=`expr ${epochtime} - ${thistime}`
#
## If the time has not already passed AND we are close enough (<= ${margin}) then fill the database
    if [ ${difftime} -le ${margin} ]; then
      /usr/bin/mythfilldatabase >> /var/log/mythtv/mythfilldatabase.log 2>&1 &
    else
# Otherwise, it is too far in the future to run now; Schedule ourselves to run again at ${nexttime}
      echo "Current time is                "`date +"%H%M %b %d"`
      echo Setting up an 'at-job' to run at `date -d "${nexttime} UTC" +"%H%M %b %d"`
      /usr/bin/at `date -d "${nexttime} UTC" +"%H%M %b %d"` >& /dev/null <<- EOF
      	/usr/bin/mythfilldatabase >> /var/log/mythtv/mythfilldatabase.log 2>&1 &
      EOF
    fi
  else
# We have already missed the fill time.  Run now, unless at-job already gone but mythfilldatabase still working.
    [ "`pgrep mythfilldatabase`" == "" ] && /usr/bin/mythfilldatabase >> /var/log/mythtv/mythfilldatabase.log 2>&1 &
  fi
fi