#!/bin/sh

########################################################
## ez-pine-gpg-helper-recipient                       ##
## part of ez-pine-gpg v0.4h // gpg filters for pine  ##
## http://Business-PHP.com/opensource/ez-pine-gpg/    ##
## (c) 13 Feb 2004, Atom Emet                         ##
## (c) 16 Dec 2004, Atom Emet                         ##
## Atom {at} Business-PHP.com                         ##
## Distributed under the GNU General Public License   ##
## http://www.gnu.org/copyleft/gpl.html               ##
##                                                    ##
##  ################################################  ##
##                                                    ##
## This program is free software; you can             ##
## redistribute it and/or modify it under the terms   ##
## of the GNU General Public License as published by  ##
## the Free Software Foundation; either version 2 of  ##
## the License, or (at your option) any later         ##
## version.                                           ##
##                                                    ##
## This program is distributed in the hope that it    ##
## will be useful, but WITHOUT ANY WARRANTY; without  ##
## even the implied warranty of MERCHANTABILITY or    ##
## FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     ##
## General Public License for more details.           ##
##                                                    ##
## You should have received a copy of the GNU         ##
## General Public License along with this program;    ##
## if not, write to the                               ##
## Free Software Foundation, Inc.,                    ##
## 59 Temple Place - Suite 330,                       ##
## Boston, MA  02111-1307, USA.                       ##
########################################################

#########################################
## PATH is configured during installation
PATH=/bin:/usr/bin:/home/bnewbold/bin

########################################################################
## make sure all specified recipients have a valid key in the keyring ##
########################################################################

#####################################################
## clear out variables that might have been inherited
recipient= ; recipient_list=

#########################################
## this function checks if each recipient
## has a valid key in the keyring
## if a valid key is not found it will try to
## find a reasonable substitute
##
valid_recipient () {
    recipient=`echo ${1} | tr -d '\r'`
    if gpg --batch --list-public-keys ${recipient} 2>&- 1>&-
    then
	## if a valid public key is found that's good
	echo "-r ${recipient}"
	exit 0
    elif [ "`echo ${recipient} | egrep '.*-.*@'`" ]
    then
	echo '/////////////////////////////////////////////////////////////////////////' 1>&2
	echo "// No public key found in keyring for <${recipient}>" 1>&2
	recipient=`echo ${recipient} | sed 's/-.*@/@/'`
	echo "// Should I try encrypting to a key for <${recipient}>? [Y/n]: " | tr -d '\n' 1>&2
	read answer 0< /dev/tty
	echo 1>&2
	if [ "`echo "${answer}" | egrep -i n`" ]
	then
	    ## don't try to substitute the email address
	    exit 3
	elif gpg --batch --list-public-keys ${recipient} 2>&- 1>&-
	then
	    ## a valid public key is found after modification
	    echo "-r ${recipient}"
	    exit 0
	fi
    fi
    ## unable to find a valid key -- bail out
    echo '/////////////////////////////////////////////////////////////////////////' 1>&2
    echo "//  No valid public key found in keyring for <${recipient}>" 1>&2
    echo "// Please import a valid key for <${recipient}>" 1>&2
    echo '/////////////////////////////////////////////////////////////////////////' 1>&2
    exit 3
}

###############################################
## for each address that's given as an argument
## make sure a valid key exists in the keyring
##
for n in ${@}
do
    recipient_list="${recipient_list} `valid_recipient ${1}`" || exit 3
    shift
done

#########################################
## return a list of addresses that have a
## valid public key in the keyring
##
echo "${recipient_list}"

########################################
## unset variables we don't need anymore
##
recipient= ; recipient_list=

#######
## exit
##
exit 0