# Copyright (C) 1998-2006 by the Free Software Foundation, Inc.
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.

"""Recognizes simple heuristically delimited bounces."""

import re
import email.Iterators



def _c(pattern):
    return re.compile(pattern, re.IGNORECASE)

# This is a list of tuples of the form
#
#     (start cre, end cre, address cre)
#
# where `cre' means compiled regular expression, start is the line just before
# the bouncing address block, end is the line just after the bouncing address
# block, and address cre is the regexp that will recognize the addresses.  It
# must have a group called `addr' which will contain exactly and only the
# address that bounced.
PATTERNS = [
    # sdm.de
    (_c('here is your list of failed recipients'),
     _c('here is your returned mail'),
     _c(r'<(?P<addr>[^>]*)>')),
    # sz-sb.de, corridor.com, nfg.nl
    (_c('the following addresses had'),
     _c('transcript of session follows'),
     _c(r'<(?P<fulladdr>[^>]*)>|\(expanded from: <?(?P<addr>[^>)]*)>?\)')),
    # robanal.demon.co.uk
    (_c('this message was created automatically by mail delivery software'),
     _c('original message follows'),
     _c('rcpt to:\s*<(?P<addr>[^>]*)>')),
    # s1.com (InterScan E-Mail VirusWall NT ???)
    (_c('message from interscan e-mail viruswall nt'),
     _c('end of message'),
     _c('rcpt to:\s*<(?P<addr>[^>]*)>')),
    # Smail
    (_c('failed addresses follow:'),
     _c('message text follows:'),
     _c(r'\s*(?P<addr>\S+@\S+)')),
    # newmail.ru
    (_c('This is the machine generated message from mail service.'),
     _c('--- Below the next line is a copy of the message.'),
     _c('<(?P<addr>[^>]*)>')),
    # turbosport.com runs something called `MDaemon 3.5.2' ???
    (_c('The following addresses did NOT receive a copy of your message:'),
     _c('--- Session Transcript ---'),
     _c('[>]\s*(?P<addr>.*)$')),
    # usa.net
    (_c('Intended recipient:\s*(?P<addr>.*)$'),
     _c('--------RETURNED MAIL FOLLOWS--------'),
     _c('Intended recipient:\s*(?P<addr>.*)$')),
    # hotpop.com
    (_c('Undeliverable Address:\s*(?P<addr>.*)$'),
     _c('Original message attached'),
     _c('Undeliverable Address:\s*(?P<addr>.*)$')),
    # Another demon.co.uk format
    (_c('This message was created automatically by mail delivery'),
     _c('^---- START OF RETURNED MESSAGE ----'),
     _c("addressed to '(?P<addr>[^']*)'")),
    # Prodigy.net full mailbox
    (_c("User's mailbox is full:"),
     _c('Unable to deliver mail.'),
     _c("User's mailbox is full:\s*<(?P<addr>[^>]*)>")),
    # Microsoft SMTPSVC
    (_c('The email below could not be delivered to the following user:'),
     _c('Old message:'),
     _c('<(?P<addr>[^>]*)>')),
    # Yahoo on behalf of other domains like sbcglobal.net
    (_c('Unable to deliver message to the following address\(es\)\.'),
     _c('--- Original message follows\.'),
     _c('<(?P<addr>[^>]*)>:')),
    # kundenserver.de
    (_c('A message that you sent could not be delivered'),
     _c('^--- The header of the original'),
     _c('<(?P<addr>[^>]*)>')),
    # another kundenserver.de
    (_c('A message that you sent could not be delivered'),
     _c('^--- The header of the original'),
     _c('^(?P<addr>[^\s@]+@[^\s@:]+):')),
    # Next one goes here...
    ]



def process(msg, patterns=None):
    if patterns is None:
        patterns = PATTERNS
    # simple state machine
    #     0 = nothing seen yet
    #     1 = intro seen
    addrs = {}
    # MAS: This is a mess. The outer loop used to be over the message
    # so we only looped through the message once.  Looping through the
    # message for each set of patterns is obviously way more work, but
    # if we don't do it, problems arise because scre from the wrong
    # pattern set matches first and then acre doesn't match.  The
    # alternative is to split things into separate modules, but then
    # we process the message multiple times anyway.
    for scre, ecre, acre in patterns:
        state = 0
        for line in email.Iterators.body_line_iterator(msg):
            if state == 0:
                if scre.search(line):
                    state = 1
            if state == 1:
                mo = acre.search(line)
                if mo:
                    addr = mo.group('addr')
                    if addr:
                        addrs[mo.group('addr')] = 1
                elif ecre.search(line):
                    break
        if addrs:
            break
    return addrs.keys()