# -*- coding: UTF-8 -*-

# Copyright (c) 2007 - 2010, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.Alias

    Virtual Mail Manager's Alias class to manage e-mail aliases.

"""

from VirtualMailManager.Domain import get_gid

from VirtualMailManager.EmailAddress import EmailAddress

from VirtualMailManager.errors import AliasError as AErr

from VirtualMailManager.constants.ERROR import ALIAS_ADDR_DEST_IDENTICAL, \

     ALIAS_EXCEEDS_EXPANSION_LIMIT, ALIAS_EXISTS, NO_SUCH_ALIAS

_ = lambda msg: msg

class Alias(object):

    """Class to manage e-mail aliases."""

    __slots__ = ('_addr', '_dests', '_gid', '_dbh')

    def __init__(self, dbh, address):

        assert isinstance(address, EmailAddress)

        self._addr = address

        self._dbh = dbh

        self._gid = get_gid(self._dbh, self._addr.domainname)

        self._dests = []

        self.__load_dests()

    def __load_dests(self):

        """Loads all known destination addresses into the _dests list."""

        dbc = self._dbh.cursor()

        dbc.execute(

                'SELECT destination FROM alias WHERE gid=%s AND address=%s',

                    self._gid, self._addr.localpart)

        dests = iter(dbc.fetchall())

        if dbc.rowcount > 0:

            dest_add = self._dests.append

            for dest in dests:

                dest_add(EmailAddress(dest[0]))

        dbc.close()

    def __check_expansion(self, limit):

        """Checks the current expansion limit of the alias."""

        dcount = len(self._dests)

        failed = False

        if dcount == limit:

            failed = True

            errmsg = _(

u"""Can't add new destination to alias %(address)r.

Currently this alias expands into %(count)i/%(limit)i recipients.

One more destination will render this alias unusable.

Hint: Increase Postfix' virtual_alias_expansion_limit""")

        elif dcount > limit:

            failed = True

            errmsg = _(

u"""Can't add new destination to alias %(address)r.

This alias already exceeds it's expansion limit (%(count)i/%(limit)i).

So its unusable, all messages addressed to this alias will be bounced.

Hint: Delete some destination addresses.""")

        if failed:

            raise AErr(errmsg % {'address': str(self._addr), 'count': dcount,

                                 'limit': limit},

                       ALIAS_EXCEEDS_EXPANSION_LIMIT)

    def __delete(self, destination=None):

        """Deletes a destination from the alias, if ``destination`` is

        not ``None``.  If ``destination`` is None, the alias with all

        it's destination addresses will be deleted.

        """

        dbc = self._dbh.cursor()

        if not destination:

            dbc.execute("DELETE FROM alias WHERE gid=%s AND address=%s",

                        self._gid, self._addr.localpart)

        else:

            dbc.execute("DELETE FROM alias WHERE gid=%s AND address=%s AND \

 destination=%s",

                        self._gid, self._addr.localpart, str(destination))

        if dbc.rowcount > 0:

            self._dbh.commit()

        dbc.close()

    def __len__(self):

        """Returns the number of destinations of the alias."""

        return len(self._dests)

    def add_destination(self, destination, expansion_limit):

        """Adds the ``destination`` `EmailAddress` to the alias."""

        assert isinstance(destination, EmailAddress)

        if self._addr == destination:

            raise AErr(_(u"Address and destination are identical."),

                       ALIAS_ADDR_DEST_IDENTICAL)

        if destination in self._dests:

            raise AErr(_(

                u'The alias %(a)r has already the destination %(d)r.') %

                       {'a': str(self._addr), 'd': str(destination)},

                       ALIAS_EXISTS)

        self.__check_expansion(expansion_limit)

        dbc = self._dbh.cursor()

        dbc.execute('INSERT INTO alias (gid, address, destination) \

VALUES (%s, %s, %s)',

                    self._gid, self._addr.localpart, str(destination))

        self._dbh.commit()

        dbc.close()

        self._dests.append(destination)

    def del_destination(self, destination):

        """Deletes the specified ``destination`` address from the alias."""

        assert isinstance(destination, EmailAddress)

        if not self._dests:

            raise AErr(_(u"The alias %r doesn't exist.") % str(self._addr),

                       NO_SUCH_ALIAS)

        if not destination in self._dests:

            raise AErr(_(u"The address %(d)r isn't a destination of \

the alias %(a)r.") %

                       {'a': str(self._addr), 'd': str(destination)},

                       NO_SUCH_ALIAS)

        self.__delete(destination)

        self._dests.remove(destination)

    def get_destinations(self):

        """Returns an iterator for all destinations of the alias."""

        if not self._dests:

            raise AErr(_(u"The alias %r doesn't exist.") % str(self._addr),

                       NO_SUCH_ALIAS)

        return iter(self._dests)

    def delete(self):

        """Deletes the alias with all it's destinations."""

        if not self._dests:

            raise AErr(_(u"The alias %r doesn't exist.") % str(self._addr),

                       NO_SUCH_ALIAS)

        self.__delete()

        del self._dests[:]

del _