#!/bin/sh
#
# atw: add to whitelist
#
# for each email message on stdin, grabs the email address from
# the From: header and appends it to my personal whitelist.
#
# see http://impressive.net/people/gerald/2000/12/spam-filtering.html
#
# Gerald Oskoboiny, 18 Dec 2000
#
# $Id: atw,v 1.6 2008/07/04 05:52:44 gerald Exp $
#
# replaced with an adaptation of Hugo's improved version,
# (c) 2001 Hugo Haas - Public domain
#

PATH=/bin:/usr/bin
WHITELIST=$HOME/.whitelist
OTHERS=$HOME/.w3c-accept.all
LOCKFILE=$HOME/.whitelist.lock

umask 077

# Get a lock
lock() {
  lockfile $LOCKFILE
  # Ensure that the lock will be removed when we are done
  trap "rm -f $LOCKFILE" 0 2 3 15
  [ -f $WHITELIST ] || touch $WHITELIST 
}

# Add an email address to the whitelist
add_address() {
  grep -F -i -x -q "$1" $WHITELIST $OTHERS
  if [ $? = 1 ]
  then
    echo "$1" >> $WHITELIST
  fi
}

# Add a list of adresses
add_addresses() {
  for email in $*
  do
    add_address $email
  done
  exit
}

# If -t is given as a first argument, scan the To and Cc fields instead of 
# the From line.
if [ "$1" = '-t' ]
then
  to='-t'
  shift
fi
 
# If argument -a is given, add the list of email addresses given as arguments.
# If argument -m is given, add a single RFC822 message (from stdin).
# If argument -M is given, import a list of Mutt aliases (from stdin).
# Else read a list of RFC822 messages from stdin.

if [ "$1" = '-a' ]
then
  lock
  shift
  add_addresses $*
elif [ "$1" = '-m' ]
then
  lock
  if [ "$to" = '-t' ]
  then 
    addresses=`formail -x To -x Cc | perl -pn -e 's/,/\n/g' | perl -n -e 'chomp; s/\".*?\"//g; m/[^ ]+@[^ ]+/; $_ = $&; s/^[<]//g; s/[>]$//; print $_."\n";'`
  else
    addresses=`formail -XFrom: | formail -r -xTo: | tr -d " "`
  fi
  add_addresses $addresses
elif [ "$1" = '-M' ]
then
  addresses=`perl -n -e 'next if (! m/^\w*alias\w/); chomp; s/\".*?\"//g; m/[^ ]+@[^ ]+/; $_ = $&; s/^[<]//g; s/[>]$//; print $_."\n";'`
  add_addresses $addresses
fi

exec formail -s $0 $to -m