# Copyright (C) 1998 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

"""Standard Mailman message object.

This is a subclass of rfc822.Message but provides an extended interface which
is more convenient for use inside Mailman.  One of the important things it
provides is a writable mapping interface so that new headers can be added, or
existing headers modified.

"""

import sys
import string
import time
from types import StringType

from Mailman import mm_cfg

# Python 1.5's version of rfc822.py is buggy and lacks features we
# depend on -- so we always use the up-to-date version distributed
# with Mailman.
from Mailman.pythonlib import rfc822



class Message(rfc822.Message):
    """This class extends the standard rfc822.Message object.

    It provides some convenience functions for getting certain interesting
    information out of the message.

    """
    def __init__(self, fp):
        rfc822.Message.__init__(self, fp)
        if self.seekable:
            self.rewindbody()
        self.body = self.fp.read()

    def GetSender(self, use_envelope=None):
        """Return the address considered to be the author of the email.

        This can return either the From: header, the Sender: header or the
        envelope header (a.k.a. the unixfrom header).  The first non-empty
        header value found is returned.  However the search order is
        determined by the following:

        - If mm_cfg.USE_ENVELOPE_SENDER is true, then the search order is
          Sender:, From:, unixfrom

        - Otherwise, the search order is From:, Sender:, unixfrom

        The optional argument use_envelope, if given overrides the
        mm_cfg.USE_ENVELOPE_SENDER setting.  It should be set to either 0 or 1
        (don't use None since that indicates no-override).

        unixfrom should never be empty.

        """
        senderfirst = mm_cfg.USE_ENVELOPE_SENDER
        if use_envelope is not None:
            senderfirst = use_envelope
        if senderfirst:
            headers = ('sender', 'from')
        else:
            headers = ('from', 'sender')
        for h in headers:
            realname, address = self.getaddr(h)
            # TBD: previous code said: "We can't trust that any of the headers
            # really contained an address".  I don't know if that's still true
            # or not, but we still test this
            if address and type(address) == StringType:
                return string.lower(address)
        # Didn't find a non-empty header, so let's fall back to the unixfrom
        # address.  This should never be empty, but if it ever is, it's
        # probably a Really Bad Thing.
        #
        # We also don't do all the elaboration that the old
        # GetEnvelopeSender() did.  We just assume that if the unixfrom
        # exists, the second field is the address.  This is what GetSender()
        # always did.
        if self.unixfrom:
            return string.lower(string.split(self.unixfrom)[1])
        else:
            # TBD: now what?!
            return None

    def __str__(self):
        # TBD: should this include the unixfrom?
        return string.join(self.headers, '') + '\n' + self.body



class OutgoingMessage(Message):
    def __init__(self, text=''):
        from Mailman.pythonlib.StringIO import StringIO
        # NOTE: text if supplied must begin with valid rfc822 headers.  It can
        # also begin with the body of the message but in that case you better
        # make sure that the first line does NOT contain a colon!
        Message.__init__(self, StringIO(text))



class UserNotification(OutgoingMessage):
    def __init__(self, recip, sender, subject=None, text=''):
        OutgoingMessage.__init__(self, text)
        if subject is None:
            subject = '(no subject)'
        self['Subject'] = subject
        self['From'] = sender
        self['To'] = recip
        self.recips = [recip]