#!/bin/bash

# Hacky wrapper for BSD cal. Sends simple calendars to standard output.
#
# Usage: mycal [month] [year]
# If no month or year is given the current month is shown.
#  year --- by itself must be 4-digits. Otherwise 2-digits will do.
#           if omitted the next matching month in the future is shown.
# month --- a number or any non-ambiguous prefix of the English name
#           if omitted the whole year is shown.
#
# This is somewhat more understanding of what I usually want than cal by itself.
# For example: "cal 9" gives a calendar for the year 0009.
#              "mycal 9" gives a calendar for "next september".
#
# Note that GNU cal or gcal is quite a bit more advanced than BSD cal. It
# doesn't interpret the command line in exactly the same way as this hack.
#
# What I really want is a command line program that will output time+date in any
# format you ask for and takes any old string as input (doing its best). Please
# email me this program :-).
#
# Iain Murray August 2005

# Only spit out whole year if I specify 4 digit year. Otherwise assume I wanted
# a month.
if echo "$1" | grep '^[12][0123456789]\{3\}$' > /dev/null 2> /dev/null ; then
	cal "$1"
	exit
fi

# Allow me to specify months as a string
month=`echo "$1" | sed \
	-e 's/^ja.*/01/i' \
	-e 's/^f.*/02/i' \
	-e 's/^mar.*/03/i' \
	-e 's/^ap.*/04/i' \
	-e 's/^may/05/i' \
	-e 's/^jun.*/06/i' \
	-e 's/^jul.*/07/i' \
	-e 's/^au.*/08/i' \
	-e 's/^s.*/09/i' \
	-e 's/^o.*/10/i' \
	-e 's/^n.*/11/i' \
	-e 's/^d.*/12/i'`

if [ "$month" ] ; then
	if echo "$month" | grep '^[01]\?[0123456789]$' > /dev/null 2> /dev/null ; then
		true
	else
		echo `basename $0`: Sorry, I do not understand which month you want.
		exit
	fi
else
	month=`date +'%m'`
fi

if [ "$2" ] ; then
	# allow two digit years (although evil)
	year="`echo "$2" | sed -e 's/^\([123456789]\)$/200\1/' -e 's/^\([012345].\)$/20\1/' -e 's/^\([6789].\)$/19\1/'`"
else
	# grab next month in the future if year not specified
	if [ "$month" -ge "`date +'%m'`" ] ; then
		year=`date +'%Y'`
	else
		year=$((`date +'%Y'`+1))
	fi
fi

cal "$month" "$year"