# Copyright (C) 2011-2016 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/>.

"""Ban manager."""

import re

from mailman import public
from mailman.database.model import Model
from mailman.database.transaction import dbconnection
from mailman.database.types import SAUnicode
from mailman.interfaces.bans import IBan, IBanManager
from sqlalchemy import Column, Integer
from zope.interface import implementer


@public
@implementer(IBan)
class Ban(Model):
    """See `IBan`."""

    __tablename__ = 'ban'

    id = Column(Integer, primary_key=True)
    email = Column(SAUnicode, index=True)
    list_id = Column(SAUnicode, index=True)

    def __init__(self, email, list_id):
        super().__init__()
        self.email = email
        self.list_id = list_id


@public
@implementer(IBanManager)
class BanManager:
    """See `IBanManager`."""

    def __init__(self, mailing_list=None):
        self._list_id = (None if mailing_list is None
                         else mailing_list.list_id)

    @dbconnection
    def ban(self, store, email):
        """See `IBanManager`."""
        bans = store.query(Ban).filter_by(email=email, list_id=self._list_id)
        if bans.count() == 0:
            ban = Ban(email, self._list_id)
            store.add(ban)

    @dbconnection
    def unban(self, store, email):
        """See `IBanManager`."""
        ban = store.query(Ban).filter_by(
            email=email, list_id=self._list_id).first()
        if ban is not None:
            store.delete(ban)

    @dbconnection
    def is_banned(self, store, email):
        """See `IBanManager`."""
        list_id = self._list_id
        if list_id is None:
            # The client is asking for global bans.  Look up bans on the
            # specific email address first.
            bans = store.query(Ban).filter_by(email=email, list_id=None)
            if bans.count() > 0:
                return True
            # And now look for global pattern bans.
            bans = store.query(Ban).filter_by(list_id=None)
            for ban in bans:
                if (ban.email.startswith('^') and
                        re.match(ban.email, email, re.IGNORECASE) is not None):
                    return True
        else:
            # This is a list-specific ban.
            bans = store.query(Ban).filter_by(email=email, list_id=list_id)
            if bans.count() > 0:
                return True
            # Try global bans next.
            bans = store.query(Ban).filter_by(email=email, list_id=None)
            if bans.count() > 0:
                return True
            # Now try specific mailing list bans, but with a pattern.
            bans = store.query(Ban).filter_by(list_id=list_id)
            for ban in bans:
                if (ban.email.startswith('^') and
                        re.match(ban.email, email, re.IGNORECASE) is not None):
                    return True
            # And now try global pattern bans.
            bans = store.query(Ban).filter_by(list_id=None)
            for ban in bans:
                if (ban.email.startswith('^') and
                        re.match(ban.email, email, re.IGNORECASE) is not None):
                    return True
        return False

    @dbconnection
    def __iter__(self, store):
        """See `IBanManager`."""
        yield from store.query(Ban).filter_by(list_id=self._list_id)