# ackmail.rc -- procmail rc to acknowledge mail (with either a 
#		vacation message, or an acknowledgement)
#
# $Id: ackmail.rc,v 1.15 1995/08/18 18:51:39 aks Exp $
#
#   Copyright (C) 1995  Alan K. Stebbens <aks@hub.ucsb.edu>
#
#   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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
#
# Usage:
#
#   After setting the variables below appropriately, add the following
#   to your .procmailrc:
#
#      INCLUDERC=ackmail.rc
#
# Features:
#
#  If the file $VACAMSG exists, it is assumed that the user is in
#  "vacation mode", and mail will be acknowledged with the contents of
#  the $VACAMSG file, with the subject line appended with "[on
#  vacation]".
#
#  If $VACAMSG doesn't exist, and $ACKMSG does, mail will be
#  acknowledged with the contents of $ACKMSG with the subject line
#  appended with "[acknowledgment]".
#
#  If neither the file $ACKMSG nor $VACAMSG exists, this recipe does
#  nothing.
#
#  Mail from any daemon or the usual set of mailing lists will not be
#  acknowledged (uses ^FROM_DAEMON).
#
#  Mail from any of a set of configured users ($NOACKS) will not be
#  acknowledged (be default, this includes the user).
#
#  Mail from any user will only be acknowledged once per day.
#
#  Regardless of whether or not "ackmail.rc" acknowledges the mail, any
#  recipes following the INCLUDERC will continue to filter the incoming
#  mail (that is, it is not considered to be delivered).
#
# Before including the "ackmail.rc" file, be sure to setup the following
# variables: 
#
# MY_ADDR	- preferred email address for the user
#
# MY_NAMES	- regex matcing personal names & alternatives;
#		  ultimately, only mail addressed to $MY_NAMES
#		  will be acknowledged; defaults to the
#		  contents of $SIGNATURE or $HOME/.signature, in
#		  that order.
#
# NOACKS	- regex matching people from whom to NOT 
#		  acknowledge mail; defaults to $MY_ADDR
#
# NOACKFILE	- path to a file containing regexps of addresses to not
#		  acknowledge
#
# ACKS		- file containing the acknowledgment cache;
#		  defaults to $MAILDIR/.acks.cache
#
# ACKMSG	- file containing the message to reply with;
#		  defaults to ackmsg
#
# VACAMSG	- file containing the message to reply with;
#		  defaults to vacation.msg
#
# FROMSIG	- From: header to use in the auto-ack; defaults
#		  to "Mailer-Daemon of $USER"
#
# MUA		- define as one of the keywords below to tell the
#		  recipe on how to calculate the unread mail:
#  MUA=default	- your unread mail sits in $DEFAULT (you don't filter
#		  mail into folders)
#  MUA=mh	- your mail is filtered into the MH +inbox; tries to
#		  use any Unseen-Sequence, or calculates it from the
#		  output of "folders +inbox".
#  MUA=XXXXX    - causes a recipe named "unread-XXXXX.rc" to be
#		  invoked (if it exists) to calculate the number
#		  of unread messages and returned in $UNREAD.
#		  
#
# And be sure PATH includes the directory containing "formail".

# If the mail is directly to me, and not an auto-reply itself 
# then do the auto-ack 

MY_NAMES=${MY_NAMES:-${SIGNATURE:-`cat $HOME/.signature 2>/dev/null`}}
ACKS=${ACKS:-ackmail.cache}
ACKMSG=${ACKMSG:-ackmsg}
VACAMSG=${VACAMSG:-vacation.msg}
FROMSIG=${FROMSIG:-"Mailer-Daemon of $USER"}
NOACKS=${NOACKS:-$MY_ADDR}
NOACKFILE=${NOACKFILE:-''}

# Handy regexp patterns (taken from "headers.rc")
PRE_ADDR_SPAN='(.*[^-(.%@a-zA-Z0-9])?'
POST_ADDR_SPAN='(([^),.!:a-zA-Z0-9].*)?(,|$[^>]))'
FROMHDR="(^(((Resent-)?(From|Sender)|X-Envelope-From):|>?From )$PRE_ADDR_SPAN)"

# Begin the tests
# 1. Is it addressed to me (using any of my names)?
# 2. Is there an acknowledgement file or vacation message file?
# 3. Is the mail NOT from any kind of daemon
# 4. Is the mail NOT from a mailing list manager which procmail doesn't know
# 5. Does the subject NOT have any text indicating some kind of automatic
#    reply mechanism has already taken place?
# 6. Is this NOT a message we generated (a bounce, maybe)?
# 7. Is the message NOT from anyone on our "noack" list?

# If you need to debug your configuration of ackmail.rc, just "touch
# ackmail.log" and the recipe below will log the ackmail.rc activity to
# ackmail.log.  When you are satisfied with your configuration, simply
# remove ackmail.log and logging will stop.

:0
* ? test -f ackmail.rc.log
{ 
  OLDACKLOGFILE=$LOGFILE
  LOGFILE=ackmail.rc.log 
  LOGABSTRACT=all
  VERBOSE=on
}

# Get the best return address without names & comments
SENDER=`formail -rtzx To:`

:0ch
* $ ^TO($USER|$MY_ADDR|$MY_NAMES)
* ? test -f $ACKMSG -o -f $VACAMSG
* ! ^FROM_DAEMON
* $! $FROMHDR(Majordomo|Listserv)
* ! ^Subject: .*(\[(ack(nowledge?ment)?|on vacation)\]|\
		auto(matic)[- ]reply|\
		away from mail|\
		out of town|\
		can ?not (reply|answer)|\
		(on |via )vacation( program)?)
* $! ^X-Loop: $MY_ADDR
* $! $FROMHDR($NOACKS)$POST_ADDR_SPAN
{
    # Okay -- we're doing to do the auto-ack or vacation mail
    #
    # We're forking for the auto-ack, shut up comsat, and assume that,
    # in this process, the mail is delivered
    DELIVERED=yes
    COMSAT=off

    # Don't output logfile info; the user can query $ACKS to see which
    # users have been acknowledged.  This only affects the child
    # process.
    LOGABSTRACT=no

    # Check for a NOACKFILE; if it exists, and if the sender matches one
    # of the regexps within the NOACKFILE, then do not ack this mail
    :0h
    * ? test -n "$NOACKFILE" -a -f "$NOACKFILE"
    * ? echo "$SENDER" | egrep -s -f "$NOACKFILE"
    { HOST=_do_not_ack_this_user }

    # Check the mail to see if we have replied recently, and if so, if
    # we should reply again
    DATE=`date +'%D'`

    # Get the subject
    :0 ch
    SUBJ=| formail -zX'Subject:' | sed -e 's/["~]//g' -e 's/^ *[Rr]e: *//g'
    SUBJ="${SUBJ:-'(no subject)'}"

    # Get which file: "vacation.msg" has precedence over "ackmsg"
    :0
    * ? test -f $VACAMSG
    { ACKFILE=$VACAMSG	ACKM='on vacation' }
    :0 E
    { ACKFILE=$ACKMSG	ACKM='acknowledgment' }

    # Check the cache for a recent ack (a successful grep "delivers" the
    # mail)
    LOCKFILE=$ACKS.lock
    :0 Wh
    | fgrep -i -s "$SENDER $DATE" $ACKS

    # Not in the $ACKS file; add it
    JUNK=`(fgrep -i -v "$SENDER" $ACKS ; echo "$SENDER $DATE" ) >$ACKS.new ;
	  rm -f $ACKS ; mv $ACKS.new $ACKS `

    # Release the lock
    LOCKFILE
    
    # Replace the headers with a reply

    # (Note: do not use -k here; "h" recipes include the blank
    # line in the headers, and formail -r generates a blank line
    # also.  If you use '-k', then the original blank line will 
    # be kept, and the additional will be added, resulting
    # in two blank lines).

    :0 fhw
    | formail -rtI"From:       $FROMSIG" \
		-I"Reply-To:   $MY_ADDR" \
		-I"Precedence: junk" \
		-I"Subject:    Re: $SUBJ [$ACKM]" \
		-I"X-Loop:     $MY_ADDR" \
		-I"References:"

    # If formail failed, it is because it couldn't be found
    # avoid acks in this case
    :0 e
    { LOG="****Error: Formail failed in ackmail.rc at `date`
"
      HOST=_stop_processing_now
    }
      
    # Replace the body with the ack message
    :0 fbw
    | cat $ACKFILE

    # If the cat $ACKFILE failed, it is probably because ackfile can't
    # be read; in this case, create a reasonable reply
    :0 efbw
    | echo "Your mail concerning '$SUBJECT' was received." ; \
      echo "I'll reply to it as soon as I can."

    # Now maybe do some substitutions, depending upon whether or not the
    # particular strings exist.
    :0 fBb
    * $SUBJECT
    | sed -e "s~\$SUBJECT~$SUBJ~g"

    :0 fBb
    * $SENDER
    | sed -e "s~\$SENDER~$SENDER~g"

    # If the string $UNREAD is in the message, then figure out
    # how many unread messages and substitute it
    :0 B
    * $UNREAD
    { 
      UNREAD=no			# by default

      # Define the MUA if it isn't defined already
      :0
      * MUA ?? !.+
      * ? test -f guess-mua.rc
      { INCLUDERC=guess-mua.rc }

      # For any MUA keyword, there should be a corresponding
      # unread-$MUA.rc file.
      :0
      * MUA ?? .+
      * ? test -f unread-$MUA.rc
      { INCLUDERC=unread-$MUA.rc }

      # Finally, substitute UNREAD into the current body
      :0 fb
      | sed -e "s~\$UNREAD~$UNREAD~g"
    }
	
    # Finally, deliver it
    :0 w
    ! -oi -t
    
    HOST=end_of_processing	# just in case sendmail failed
}

# Undo any debug logging
:0
* LOGFILE ?? ackmail\.rc\.log
{ 
  VERBOSE=no
  LOGABSTRACT=yes
  LOGFILE=$OLDACKLOGFILE
  OLDACKLOGFILE
}