#! /bin/sh

year=$(date +%Y)
year=2010

#
# Find the nth wday in a given month
#
# Parameters: month year n wday
#             n=10 means last
#
mon_day()
{
    case $4 in
    sun) wday="1-2";;
    mon) wday="4-5";;
    fri) wday="16-17";;
    esac

    nth=$3

    n=1
    for mon in $(cal $1 $2 | tail -n +3 | cut -c$wday)
    do
	if [ $n -eq $nth ]
	then
	    echo $mon
	    return
	else
	    n=$[n+1]
	fi
    done
    if [ $nth -eq 10 ]
    then
	echo $mon
    fi
}

# LUG-WHV: In einer geraden Kalenderwoche Dienstag um 19:30 Uhr
#   delta=+16; for i in `seq 1 27`; do
#     date=`date -d now+${delta}days +%Y-%m-%d`; delta=$[delta + 14];
#     printf "%s|19:30|WHV|Linux User Group Wilhelmshaven|W\'haven|http://www.lug-whv.de/\n" $date
#   done
dates_lugwhv()
{
    day=$[ $(date +%j) - 1]
    day=0

    for i in $(seq 1 20)
    do
	if [ "$(date -d now-${day}days+${i}days  +%V-%u)" = "02-2" ]
	then
	    delta=$i
	fi
    done

    delta=$[delta + 9]
    for i in $(seq 1 28)
    do
	date=`date -d now-${day}days+${delta}days +%Y-%m-%d`
	delta=$[delta + 14];
	printf "%s|19:30|WHV|Linux User Group Wilhelmshaven|W\'haven|http://www.lug-whv.de/\n" $date
    done
}

#
# BUG OL: jeder 3. Montag eines Monats
#
dates_bugol()
{
    for m in $(seq 1 12)
    do
	printf '%04d-%02d-%02d|19:00|OL|BSD User Group|Havana|http://www.bugol.de/\n' \
	    $year $m $(mon_day $m $year 3 mon)
    done
}

#
# LUG-HB: Treffen: Jeden 3. Sonntag im Monat
#
dates_lughb_old()
{
    for m in $(seq 1 12)
    do
	printf '%04d-%02d-%02d|19:00|HB|Linux User Group Bremen|Bremen|http://www.lug-bremen.info/\n' \
	    $year $m $(mon_day $m $year 3 sun)
    done
}

#
# Jeder Sonntag
#
dates_lughb()
{
    day=$[ $(date +%j) - 1]
    day=0

    delta=28
    for i in $(seq 1 53)
    do
	date=`date -d now-${day}days+${delta}days +%Y-%m-%d`
	delta=$[delta + 7];
	printf '%s|19:00|HB|Linux User Group Bremen|Bremen|http://www.lug-bremen.info/\n' $date
    done
}

#
# CCO: jeder 1. und 3. Freitag im Vereinsheim
#
dates_cco()
{
    for m in $(seq 1 12)
    do
	printf '%04d-%02d-%02d|19:30|FRI|Linux Gruppe Ostfriesland|Hesel|http://linux.cco-ev.de/\n' \
	    $year $m $(mon_day $m $year 1 fri)
	printf '%04d-%02d-%02d|19:30|FRI|Linux Gruppe Ostfriesland|Hesel|http://linux.cco-ev.de/\n' \
	    $year $m $(mon_day $m $year 3 fri)
    done
}

#
# LUGO: letzer Montag und 2. Freitag
#
dates_lugo()
{
    for m in $(seq 1 12)
    do
	printf '%04d-%02d-%02d|19:00|OL|Oldenburger Linux-Stammtisch|Bei Beppo|http://oldenburg.linux.de/\n' \
	    $year $m $(mon_day $m $year 2 fri)
	printf '%04d-%02d-%02d|20:00|OL|Oldenburger Linux-Stammtisch|Bei Beppo|http://oldenburg.linux.de/\n' \
	    $year $m $(mon_day $m $year 10 mon)
    done
}

if [ $# -lt 1 ]
then
    type=lugo
else
    type=$1
fi

case $type in
bugol) dates_bugol;;
lugo) dates_lugo;;
lughb) dates_lughb;;
lugwhv) dates_lugwhv;;
cco) dates_cco;;
help) echo "bugol, lughb, cco";;
esac