#!/bin/bash

version="0.41.0"

# --- Configuration variables ---

# the filter executable:
FILTER_BIN=/usr/bin/postconfirmc

# Mailman's distributed mailman executable:
MAILMAN_BIN=/usr/lib/mailman/mail/mailman

# Mail handler executable
SENDMAIL_BIN=/usr/sbin/sendmail

# Where we store mailman commands identified as spam
SPAM_STASH=/a/postconfirm/cache

# --- Re-invoke with logging ---
if [ "$RUNNING" != "$0" ]; then
   export RUNNING=$0
   $0 "$@" 2>&1 | logger -t postconfirmw
   exit ${PIPESTATUS[0]}
fi

# Command line arguments
## The 'action' argument is set by the caller.  Mailman will set 'action' to one
## of "post", "owner", or "admin".  The postfix group-alias and draft-alias lists
## will set 'action' to "filter".
action="$1"
dest="$2"
domain="$3"

[ "$domain" ] || domain=${RECIPIENT##*@}

# Debug switch
DEBUG=""
# Uncomment for debug:
#DEBUG=1

# ----------------
function die() {
    echo -e "\n$program: error: $*" > /dev/stderr
    exit 1
}

# ----------------
function note() { 
    [ "$DEBUG" ] && echo -e "$*"
    logger -i -p user.info -t postconfirmw "$*"
}

# --- Start of script proper ---

if [ "$DEBUG" ]; then
    echo "-----------------------------"
    date
    cat <<-EOF
	Prog: $0
	Args: $@
	User: $(whoami)
	USER     : $USER
	SENDER   : $SENDER
	RECIPIENT: $RECIPIENT
	EOF
fi
unset HOME

[ -d $SPAM_STASH ] || mkdir -p $SPAM_STASH

SEND_LOCALPART=${SENDER%@*}
RECV_LOCALPART=${RECIPIENT%@*}

if [ "${SEND_LOCALPART##*-}" = "bounces" -a "${RECV_LOCALPART##*-}" = "owner" ]; then
    note "Mailman response piped directly to mailman"
    $MAILMAN_BIN "$action" "$dest"
elif [ "$action" = post -o "$action" = owner -o "$action" = admin -o "$action" = filter ]; then
    # Using a temp file to hold the message isn't pretty, but we need to catch the exit
    # code from tmda_filter to decide whether to pipe stuff into mailman or not, and
    # neither $? or $PIPESTATUS[0] lets us do that inside the pipe itself.
    tmp=$(mktemp -t postconfirm-tmp-XXXXXX)
    out=$(mktemp -t postconfirm-out-XXXXXX)
    err=$(mktemp -t postconfirm-err-XXXXXX)

    if [ "$action" = filter ]; then
	cat - > $tmp
    else
	# Add List-Id: so that we're able to calculate the Archived-At: header later.
	# This will be overwritten by Mailman during its processing.
	cat - | formail -I "List-ID: <$dest.ietf.org>" > $tmp
    fi

    note "Input piped to postconfirm: '$FILTER_BIN confirm'"
    $FILTER_BIN confirm < $tmp 2>$err | /a/postconfirm/insert_expanded_headers "$dest" > $out
    errnum=${PIPESTATUS[0]}
    
    if [ "$DEBUG" ]; then
	echo "--- $(date +%Y-%m-%d_%H:%M): $* [$SENDER => $RECIPIENT] ---"	>> /tmp/postconfirm-debug.log
	head $out								>> /tmp/postconfirm-debug.log
    fi

    if   [ $errnum == 0 ]; then
	if [ "$action" = filter ]; then
	    note "Input forwarded to MTA ($SENDMAIL_BIN -f $SENDER $dest@$domain)"
	    $SENDMAIL_BIN -f "$SENDER" "$dest@$domain" < $out
	else
	    note "Input forwarded to mailman ($MAILMAN_BIN $action $dest)"
	    $MAILMAN_BIN "$action" "$dest" < $out
        fi
    elif [ $errnum == 1 ]; then
	note "Error return $errnum from $FILTER_BIN -- not forwarding"
	[ "$DEBUG" ] && cat $err
    else
	if [ "$action" = filter ]; then
	    echo "$FILTER_BIN failure (error $errnum) -- input forwarded to MTA"
	    $SENDMAIL_BIN -f "$SENDER" "$dest@$domain" < $tmp
	else
	    echo "$FILTER_BIN failure (error $errnum) -- input forwarded to mailman"
	    $MAILMAN_BIN "$action" "$dest" < $tmp
	fi
    fi
    [ "$DEBUG" ] || rm -f $tmp $out $err
else
    cmd=$(mktemp -t postconfirm-cmd-XXXXX)
    cat - > $cmd
    spamflag=$(echo $(formail -c -x "X-Spam-Flag" < $cmd))
    if [ "$spamflag" = "YES" ]; then
	spam=$(mktemp "$SPAM_STASH/spamXXXXXXXX")
	mv $cmd $spam
	echo "Mailman command flagged as spam, saved as $spam"
    else
	actn=$(mktemp "$SPAM_STASH/actnXXXXXXXX")
	mv $cmd $actn
	echo "Command '$action': <$SENDER> -> $dest  piped to mailman after spam check, saved as $actn"
	$MAILMAN_BIN "$action" "$dest" < $actn
	#rm -f $cmd
    fi
fi

true