#!/bin/sh

set -o pipefail
set -eu

myemail=$(mktemp)
cat - > $myemail
email=$(maddr -a -h From $myemail 2>/dev/null)
replyto=$(maddr -h Reply-To $myemail 2>/dev/null)
records=$(host -t txt _dmarc.${email#*@})
# cleanup the lines to drop ; and " and have every fields space separated
savIFS=${IFS}
export IFS=' ";'
set -- $records
export IFS=${savIFS}
case "$@" in
*\ p=reject\ *|*\ p=quarantine\ *)
	fullmail=$(maddr -h From $myemail 2>/dev/null)
	newfrom="${fullmail%<${email}>} via <mmtest@freebsd.org>"
	if [ -z ${replyto} ]; then
		msed "/from/c/$newfrom/;/Reply-To/a/$fullmail/" $myemail 2>/dev/null
	else
		msed "/from/c/$newfrom/;/reply-to/s/.*/&, $fullmail/" $myemail 2>/dev/null
	fi
	;;
*)
	cat $myemail
esac
rm $myemail