# Copyright (C) 1998-2009 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman 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 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman 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
# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.

"""Yahoo! has its own weird format for bounces."""

import re
import email
from email.Utils import parseaddr

tcre = re.compile(r'message\s+from\s+yahoo\.\S+', re.IGNORECASE)
acre = re.compile(r'<(?P<addr>[^>]*)>:')
ecre = re.compile(r'--- Original message follows')



def process(msg):
    # Yahoo! bounces seem to have a known subject value and something called
    # an x-uidl: header, the value of which seems unimportant.
    sender = parseaddr(msg.get('from', '').lower())[1] or ''
    if not sender.startswith('mailer-daemon@yahoo'):
        return None
    addrs = []
    # simple state machine
    #     0 == nothing seen
    #     1 == tag line seen
    state = 0
    for line in email.Iterators.body_line_iterator(msg):
        line = line.strip()
        if state == 0 and tcre.match(line):
            state = 1
        elif state == 1:
            mo = acre.match(line)
            if mo:
                addrs.append(mo.group('addr'))
                continue
            mo = ecre.match(line)
            if mo:
                # we're at the end of the error response
                break
    return addrs
