# -*- coding: utf-8 -*-
# Copyright 2020 The Matrix.org Foundation C.I.C.
#
# 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.
import logging
from typing import Tuple

from synapse.api.constants import EventTypes
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.rest import admin
from synapse.rest.client.v1 import login, room
from synapse.types import create_requester
from synapse.util.stringutils import random_string

from tests import unittest

logger = logging.getLogger(__name__)


class EventCreationTestCase(unittest.HomeserverTestCase):
    servlets = [
        admin.register_servlets,
        login.register_servlets,
        room.register_servlets,
    ]

    def prepare(self, reactor, clock, hs):
        self.handler = self.hs.get_event_creation_handler()
        self.persist_event_storage = self.hs.get_storage().persistence

        self.user_id = self.register_user("tester", "foobar")
        self.access_token = self.login("tester", "foobar")
        self.room_id = self.helper.create_room_as(self.user_id, tok=self.access_token)

        self.info = self.get_success(
            self.hs.get_datastore().get_user_by_access_token(self.access_token,)
        )
        self.token_id = self.info["token_id"]

        self.requester = create_requester(self.user_id, access_token_id=self.token_id)

    def _create_duplicate_event(self, txn_id: str) -> Tuple[EventBase, EventContext]:
        """Create a new event with the given transaction ID. All events produced
        by this method will be considered duplicates.
        """

        # We create a new event with a random body, as otherwise we'll produce
        # *exactly* the same event with the same hash, and so same event ID.
        return self.get_success(
            self.handler.create_event(
                self.requester,
                {
                    "type": EventTypes.Message,
                    "room_id": self.room_id,
                    "sender": self.requester.user.to_string(),
                    "content": {"msgtype": "m.text", "body": random_string(5)},
                },
                txn_id=txn_id,
            )
        )

    def test_duplicated_txn_id(self):
        """Test that attempting to handle/persist an event with a transaction ID
        that has already been persisted correctly returns the old event and does
        *not* produce duplicate messages.
        """

        txn_id = "something_suitably_random"

        event1, context = self._create_duplicate_event(txn_id)

        ret_event1 = self.get_success(
            self.handler.handle_new_client_event(self.requester, event1, context)
        )
        stream_id1 = ret_event1.internal_metadata.stream_ordering

        self.assertEqual(event1.event_id, ret_event1.event_id)

        event2, context = self._create_duplicate_event(txn_id)

        # We want to test that the deduplication at the persit event end works,
        # so we want to make sure we test with different events.
        self.assertNotEqual(event1.event_id, event2.event_id)

        ret_event2 = self.get_success(
            self.handler.handle_new_client_event(self.requester, event2, context)
        )
        stream_id2 = ret_event2.internal_metadata.stream_ordering

        # Assert that the returned values match those from the initial event
        # rather than the new one.
        self.assertEqual(ret_event1.event_id, ret_event2.event_id)
        self.assertEqual(stream_id1, stream_id2)

        # Let's test that calling `persist_event` directly also does the right
        # thing.
        event3, context = self._create_duplicate_event(txn_id)
        self.assertNotEqual(event1.event_id, event3.event_id)

        ret_event3, event_pos3, _ = self.get_success(
            self.persist_event_storage.persist_event(event3, context)
        )

        # Assert that the returned values match those from the initial event
        # rather than the new one.
        self.assertEqual(ret_event1.event_id, ret_event3.event_id)
        self.assertEqual(stream_id1, event_pos3.stream)

        # Let's test that calling `persist_events` directly also does the right
        # thing.
        event4, context = self._create_duplicate_event(txn_id)
        self.assertNotEqual(event1.event_id, event3.event_id)

        events, _ = self.get_success(
            self.persist_event_storage.persist_events([(event3, context)])
        )
        ret_event4 = events[0]

        # Assert that the returned values match those from the initial event
        # rather than the new one.
        self.assertEqual(ret_event1.event_id, ret_event4.event_id)

    def test_duplicated_txn_id_one_call(self):
        """Test that we correctly handle duplicates that we try and persist at
        the same time.
        """

        txn_id = "something_else_suitably_random"

        # Create two duplicate events to persist at the same time
        event1, context1 = self._create_duplicate_event(txn_id)
        event2, context2 = self._create_duplicate_event(txn_id)

        # Ensure their event IDs are different to start with
        self.assertNotEqual(event1.event_id, event2.event_id)

        events, _ = self.get_success(
            self.persist_event_storage.persist_events(
                [(event1, context1), (event2, context2)]
            )
        )

        # Check that we've deduplicated the events.
        self.assertEqual(len(events), 2)
        self.assertEqual(events[0].event_id, events[1].event_id)
