#!/bin/sh
# generates the upcoming meetups for Funkfeuer Graz Homepage
#
# this script should be called by cron every day (night)
# how far in the future should i go?
LIMIT=3

# uncomment to enable debug
#DEBUG=1

# where to put the output files?
NEXT_FILE="next.html"
AFTER_FILE="after.html"

DOW=`date +"%u"`
if [ $DOW -eq 1 ]; then
  DOM=`date +"%e"`
  TS=`date +"%s"`
else
  DOM=`date --date="next monday" +"%e"`
  TS=`date --date="next monday" +"%s"`
fi

MEETUPS=""
CNT=0
while true; do
  if [ -n "$DEBUG" ]; then echo -n "check day($TS): "`date --date="@$TS" +"%d.%m.%Y"`; fi

  if [ $DOM -le 7 ] || ([ $DOM -ge 15 ] && [ $DOM -le 21 ]); then
    if [ -n "$DEBUG" ]; then echo " -> ok"; fi
    MEETUPS="$MEETUPS $TS"
    CNT=$((CNT + 1))
    if [ $CNT -ge $LIMIT ]; then
      break;
    fi
  else
    if [ -n "$DEBUG" ]; then echo ""; fi
  fi
  TS=$((TS + (7 * 24 * 3600)))
  DOM=`date --date="@$TS" +"%e"`
done

set -- $MEETUPS
NEXT=$1
shift
FUTURE=$@

date --date="@$NEXT" +"%d.%m.%Y" > "$NEXT_FILE.new"
echo "<ul>" > "$AFTER_FILE.new"
for meetup in $FUTURE; do
  echo "  <li>"`date --date="@$meetup" +"%d.%m.%Y"`"</li>" >> "$AFTER_FILE.new"

done
echo "</ul>" >> "$AFTER_FILE.new"
mv "$NEXT_FILE.new" "$NEXT_FILE"
mv "$AFTER_FILE.new" "$AFTER_FILE"

exit 0