#!/bin/ksh
# @(#) mbiff.ksh 1.2 93/12/04
# mbiff: turn mail notification on or off.    
# 92/02/15 john h. dubois iii (john@armory.com)
# 92/03/25 rcvalert broken under 3.2v4; use mailalert instead
#          (modified so that alertprog is only given once so it can be changed)
# 92/09/26 Remove ksh dependence
# 93/12/04 Changed name from notify to mbiff; notify is a tcsh builtin

alertprog=/local/bin/mailalert
expression="^\*[ 	][ 	]*-[ 	].*[ 	]$alertprog"

# status: returns zero if mail notification is enabled; nonzero if not.
status() {
    egrep "$expression" $HOME/.maildelivery > /dev/null 2>&1
}

function help {
    echo \
"Usage: $name [on|off]
$name      tells you whether notification is on or off.
$name on   turns on immediate notification of new mail.
$name off  turns off immediate notification of new mail.

Notification status does not change between logins (when you turn
it on or off, it will remain on or off until you change it again)."
    exit 0
}

if [[ "${0##*/}" = biff ]]; then
    echo 'Use "mbiff" to turn on immediate notification of new mail.'
    name=mbiff
    help
fi

name=${0##*/}

cd
case "$1" in
on)
    if status; then
	echo "Immediate mail notification was already on."
    else
	# preserve old .maildelivery permissions
	[ -f .maildelivery ]
	hasmaildelivery=$?
	[ $hasmaildelivery = 0 ] && /bin/cp .maildelivery .maildelivery-
	# put alert line at top of .maildelivery
	echo "*	-	pipe	R	$alertprog" > .maildelivery
	[ $hasmaildelivery = 0 ] && cat .maildelivery- >> .maildelivery
	echo "Immediate mail notification is now on."
    fi
    ;;
off)
    if status; then
	# preserve old .maildelivery permissions
	/bin/cp .maildelivery .maildelivery-
	sed "\|$expression|d" .maildelivery- > .maildelivery
	echo "Immediate mail notification is now off."
    else
	echo "Immediate mail notification was already off."
    fi
    ;;
"")
    if status; then
	echo "Immediate mail notification is on."
    else
	echo "Immediate mail notification is off."
    fi
    ;;
*)
    help
    ;;
esac