#!/bin/bash
# Jim Lofft 06/19/2009
# find_alias_for_msmtp.sh
# popper email server was replaced by exchange. I replaced sendmail with this script
# which scans /etc/alias file for a valid domain email address and calls msmtp
# (https://marlam.de/msmtp)
#
# changed a little by Ovidiu Constantin <ovidiu@mybox.ro> && http://blog.mybox.ro/
#

DEFAULTEMAIL="you@domain.com"

v_recipient=0
v_msg=$(cat)       # email message contents
MSMTP=$(which msmtp || echo "/usr/local/bin/msmtp")

#
if [  "$1" = '-i'  ] ; then
   v_recipient=$2 # mailx calls sendmail with -i as the 1st param and the recipient as the second param
elif [ "$1" = '-t' ] ; then  # most other programs call sendmail with a -t option
        v_to=$(echo "$v_msg" | grep -m 1 'To: ')
        v_recipient=${v_to:4:50}
else
   v_recipient=$1 # no parameter, sendmail was called with the recipient as parameter
fi
#

if [ $v_recipient != 0 ] ; then

# trim spaces from recipient email address
 v_recipient="${v_recipient// /}"

# see if this email is to a @ domain.com
 v_domain=$(expr index "{$v_recipient}" @)

# if this email isn't to a domain, then it's a local email, so
# look up the recipient in the aliases file

        if [ "$v_domain" = 0 ]; then

                v_find_alias=$(grep -- "$v_recipient": /etc/aliases | awk '{print $2}')  #grep alias file
                v_alias_domain=$(expr index "{$v_find_alias}" @) # grep for an @domain address

                        if [ "$v_alias_domain" = 0 ]; then      # we didn't find an @, grep alias again

                                v_next_alias=$(grep -- "$v_find_alias": /etc/aliases | awk '{print $2}')
                                v_alias_domain=$(expr index "{$v_next_alias}" @)

                                 if [ "$v_alias_domain" = 0 ]; then # email someone important if no @ alias is found
                                    v_recipient=$DEFAULTEMAIL
                                 else
                                    v_recipient=$v_next_alias
                                 fi
                        else
                           v_recipient=$v_find_alias
                        fi
        fi
  # Send msmtp email
  echo "$v_msg" | $MSMTP -i $v_recipient
else
  # we're not sure who this email is for, just send it to msmtp and see what happens..
  echo "$v_msg" | $MSMTP $1 $2 $3 $4 $5
fi