#!/bin/ksh
# @(#) mailias.ksh 1.2 93/07/16
# mailias: sort mail alias & print with maximum-length lines
# 91/01/13 john h. dubois iii (john@armory.com)
# 91/02/25 Converted to use builtin shell sort.
# 93/07/16 Cleaned up a bit.

alias istrue="test 0 -ne"
alias isfalse="test 0 -eq"

# Print words passed as args with max line length
# Usage: PrintMaxLines <maxlinelength> <sep> <end> word ...
# <sep> is used to separate words on a line.
# <end> is put at the end of each line except the last.
function PrintMaxLines {
    typeset maxline=$1 sep=$2 end=$3 outline= word
    typeset -i printedline=0 extra=${#sep}+${#end}

    shift 3
    for word; do
	if [[ $(( ${#outline}+${#word}+$extra )) -gt $maxline ]]; then
	    isfalse printedline && printedline=1 || print -r "$end"
	    print -nr "$outline"
	    outline=$word
	else
	    [ -z "$outline" ] && outline=$word || outline="$outline$sep$word"
	fi
    done
    # print final line if it hasn't been printed yet
    istrue printedline && print -r "$end"
    print -r "$outline"
}

set -e

name=${0##*/}
Syntax="Syntax: $name [-h] [linelength]"

if [ "$1" = -h ]; then
    echo \
"$name: sort names on a mail alias and print it with maximum-length lines.
$Syntax

$name processes mail aliases that have this form:

alias foo user1 user2 user3 user4 user5\
user6 user7 user8

There can be any number of lines, each optionally terminated with a backslash.
The first word of the first line must be \"alias\"; the second word is the
alias name.
The alias is read from the input, and a new alias is printed on the output.
The new alias has the word \"alias\", followed by the alias name, followed
by the sorted user names.
As many names as will fit are printed on each line.
The default line length is 79 characters.
A number given on the command line will override the default.
Every line except the last one is terminated with a backslash."
    exit
fi

typeset -i maxline=79
case $# in
    0) 
	;;
    1) 
	maxline=$1;;
    *) 
	echo "$Syntax"
	exit 1;;
esac

set -o noglob

# read first line
read -r alias name line
if [ -z "$line" ]; then
    print -u2 "Not a good alias."
    exit 1
fi

if [ $alias != alias ]; then
    print -u2 'No "alias" keyword.'
    exit 1
fi

# Read the alias into var "list";
# remove trailing backslashes and any whitespace that follows them
# (whitespace is removed by read)
list="${line%\\}"
while read -r line; do
    list="$list ${line%\\}"
done 

# sort names on list
set -- $list
set -s

PrintMaxLines $maxline " " \\ alias "$name" "$@"
print -r ""