# -*- coding: utf-8 -*-
# Copyright 2017 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


class SpamChecker(object):
    def __init__(self, hs):
        self.spam_checker = None

        module = None
        config = None
        try:
            module, config = hs.config.spam_checker
        except Exception:
            pass

        if module is not None:
            self.spam_checker = module(config=config)

    def check_event_for_spam(self, event):
        """Checks if a given event is considered "spammy" by this server.

        If the server considers an event spammy, then it will be rejected if
        sent by a local user. If it is sent by a user on another server, then
        users receive a blank event.

        Args:
            event (synapse.events.EventBase): the event to be checked

        Returns:
            bool: True if the event is spammy.
        """
        if self.spam_checker is None:
            return False

        return self.spam_checker.check_event_for_spam(event)

    def user_may_invite(self, inviter_userid, invitee_userid, third_party_invite,
                        room_id, new_room, published_room):
        """Checks if a given user may send an invite

        If this method returns false, the invite will be rejected.

        Args:
            inviter_userid (str)
            invitee_userid (str|None): The user ID of the invitee. Is None
                if this is a third party invite and the 3PID is not bound to a
                user ID.
            third_party_invite (dict|None): If a third party invite then is a
                dict containing the medium and address of the invitee.
            room_id (str)
            new_room (bool): Whether the user is being invited to the room as
                part of a room creation, if so the invitee would have been
                included in the call to `user_may_create_room`.
            published_room (bool): Whether the room the user is being invited
                to has been published in the local homeserver's public room
                directory.

        Returns:
            bool: True if the user may send an invite, otherwise False
        """
        if self.spam_checker is None:
            return True

        return self.spam_checker.user_may_invite(
            inviter_userid, invitee_userid, third_party_invite, room_id, new_room,
            published_room,
        )

    def user_may_create_room(self, userid, invite_list, third_party_invite_list,
                             cloning):
        """Checks if a given user may create a room

        If this method returns false, the creation request will be rejected.

        Args:
            userid (string): The sender's user ID
            invite_list (list[str]): List of user IDs that would be invited to
                the new room.
            third_party_invite_list (list[dict]): List of third party invites
                for the new room.
            cloning (bool): Whether the user is cloning an existing room, e.g.
                upgrading a room.

        Returns:
            bool: True if the user may create a room, otherwise False
        """
        if self.spam_checker is None:
            return True

        return self.spam_checker.user_may_create_room(
            userid, invite_list, third_party_invite_list, cloning,
        )

    def user_may_create_room_alias(self, userid, room_alias):
        """Checks if a given user may create a room alias

        If this method returns false, the association request will be rejected.

        Args:
            userid (string): The sender's user ID
            room_alias (string): The alias to be created

        Returns:
            bool: True if the user may create a room alias, otherwise False
        """
        if self.spam_checker is None:
            return True

        return self.spam_checker.user_may_create_room_alias(userid, room_alias)

    def user_may_publish_room(self, userid, room_id):
        """Checks if a given user may publish a room to the directory

        If this method returns false, the publish request will be rejected.

        Args:
            userid (string): The sender's user ID
            room_id (string): The ID of the room that would be published

        Returns:
            bool: True if the user may publish the room, otherwise False
        """
        if self.spam_checker is None:
            return True

        return self.spam_checker.user_may_publish_room(userid, room_id)

    def user_may_join_room(self, userid, room_id, is_invited):
        """Checks if a given users is allowed to join a room.

        Is not called when the user creates a room.

        Args:
            userid (str)
            room_id (str)
            is_invited (bool): Whether the user is invited into the room

        Returns:
            bool: Whether the user may join the room
        """
        if self.spam_checker is None:
            return True

        return self.spam_checker.user_may_join_room(userid, room_id, is_invited)