# -*- coding: utf-8 -*-
# Copyright 2018 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.

from twisted.internet import defer

from synapse.api.errors import NotFoundError
from synapse.rest.client.v1 import room

from tests.unittest import HomeserverTestCase


class PurgeTests(HomeserverTestCase):

    user_id = "@red:server"
    servlets = [room.register_servlets]

    def make_homeserver(self, reactor, clock):
        hs = self.setup_test_homeserver("server", federation_http_client=None)
        return hs

    def prepare(self, reactor, clock, hs):
        self.room_id = self.helper.create_room_as(self.user_id)

    def test_purge(self):
        """
        Purging a room will delete everything before the topological point.
        """
        # Send four messages to the room
        first = self.helper.send(self.room_id, body="test1")
        second = self.helper.send(self.room_id, body="test2")
        third = self.helper.send(self.room_id, body="test3")
        last = self.helper.send(self.room_id, body="test4")

        store = self.hs.get_datastore()
        storage = self.hs.get_storage()

        # Get the topological token
        token = self.get_success(
            store.get_topological_token_for_event(last["event_id"])
        )
        token_str = self.get_success(token.to_string(self.hs.get_datastore()))

        # Purge everything before this topological token
        self.get_success(
            storage.purge_events.purge_history(self.room_id, token_str, True)
        )

        # 1-3 should fail and last will succeed, meaning that 1-3 are deleted
        # and last is not.
        self.get_failure(store.get_event(first["event_id"]), NotFoundError)
        self.get_failure(store.get_event(second["event_id"]), NotFoundError)
        self.get_failure(store.get_event(third["event_id"]), NotFoundError)
        self.get_success(store.get_event(last["event_id"]))

    def test_purge_wont_delete_extrems(self):
        """
        Purging a room will delete everything before the topological point.
        """
        # Send four messages to the room
        first = self.helper.send(self.room_id, body="test1")
        second = self.helper.send(self.room_id, body="test2")
        third = self.helper.send(self.room_id, body="test3")
        last = self.helper.send(self.room_id, body="test4")

        storage = self.hs.get_datastore()

        # Set the topological token higher than it should be
        token = self.get_success(
            storage.get_topological_token_for_event(last["event_id"])
        )
        event = "t{}-{}".format(token.topological + 1, token.stream + 1)

        # Purge everything before this topological token
        purge = defer.ensureDeferred(storage.purge_history(self.room_id, event, True))
        self.pump()
        f = self.failureResultOf(purge)
        self.assertIn("greater than forward", f.value.args[0])

        # Try and get the events
        self.get_success(storage.get_event(first["event_id"]))
        self.get_success(storage.get_event(second["event_id"]))
        self.get_success(storage.get_event(third["event_id"]))
        self.get_success(storage.get_event(last["event_id"]))