#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2020 The Matrix.org Foundation C.I.C.
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#

from typing import cast

from parameterized import parameterized

from twisted.internet.testing import MemoryReactor
from twisted.trial import unittest

from synapse.api.constants import EventTypes
from synapse.api.room_versions import RoomVersions
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.rest import admin
from synapse.rest.client import login, room
from synapse.server import HomeServer
from synapse.storage.database import LoggingTransaction
from synapse.storage.databases.main.events import _LinkMap
from synapse.storage.types import Cursor
from synapse.types import create_requester
from synapse.util.clock import Clock

from tests.unittest import HomeserverTestCase


class EventChainStoreTestCase(HomeserverTestCase):
    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.store = hs.get_datastores().main
        self._next_stream_ordering = 1

    @parameterized.expand([(False,), (True,)])
    def test_simple(self, batched: bool) -> None:
        """Test that the example in `docs/auth_chain_difference_algorithm.md`
        works.
        """

        event_factory = self.hs.get_event_builder_factory()
        bob = "@creator:test"
        alice = "@alice:test"
        charlie = "@charlie:test"
        room_id = "!room:test"

        # Ensure that we have a rooms entry so that we generate the chain index.
        self.get_success(
            self.store.store_room(
                room_id=room_id,
                room_creator_user_id="",
                is_public=True,
                room_version=RoomVersions.V6,
            )
        )

        create = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Create,
                    "state_key": "",
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "create"},
                },
            ).build(prev_event_ids=[], auth_event_ids=[])
        )

        bob_join = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": bob,
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "bob_join"},
                },
            ).build(prev_event_ids=[], auth_event_ids=[create.event_id])
        )

        power = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.PowerLevels,
                    "state_key": "",
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "power"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id],
            )
        )

        alice_invite = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "alice_invite"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id, power.event_id],
            )
        )

        alice_join = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": alice,
                    "room_id": room_id,
                    "content": {"tag": "alice_join"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, alice_invite.event_id, power.event_id],
            )
        )

        power_2 = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.PowerLevels,
                    "state_key": "",
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "power_2"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id, power.event_id],
            )
        )

        bob_join_2 = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": bob,
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "bob_join_2"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id, power.event_id],
            )
        )

        alice_join2 = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": alice,
                    "room_id": room_id,
                    "content": {"tag": "alice_join2"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[
                    create.event_id,
                    alice_join.event_id,
                    power_2.event_id,
                ],
            )
        )

        charlie_invite = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": charlie,
                    "sender": alice,
                    "room_id": room_id,
                    "content": {"tag": "charlie_invite"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[
                    create.event_id,
                    alice_join2.event_id,
                    power_2.event_id,
                ],
            )
        )

        events = [
            create,
            bob_join,
            power,
            alice_invite,
            alice_join,
            bob_join_2,
            power_2,
            alice_join2,
            charlie_invite,
        ]

        expected_links = [
            (bob_join, create),
            (power, bob_join),
            (alice_invite, power),
            (bob_join_2, power),
            (alice_join2, power_2),
            (charlie_invite, alice_join2),
        ]

        # We either persist as a batch or one-by-one depending on test
        # parameter.
        if batched:
            self.persist(events)
        else:
            for event in events:
                self.persist([event])

        chain_map, link_map = self.fetch_chains(events)

        # Check that the expected links and only the expected links have been
        # added.
        event_map = {e.event_id: e for e in events}
        reverse_chain_map = {v: event_map[k] for k, v in chain_map.items()}

        self.maxDiff = None
        self.assertCountEqual(
            expected_links,
            [
                (reverse_chain_map[(s1, s2)], reverse_chain_map[(t1, t2)])
                for s1, s2, t1, t2 in link_map.get_additions()
            ],
        )

        # Test that everything can reach the create event, but the create event
        # can't reach anything.
        for event in events[1:]:
            self.assertTrue(
                link_map.exists_path_from(
                    chain_map[event.event_id], chain_map[create.event_id]
                ),
            )

            self.assertFalse(
                link_map.exists_path_from(
                    chain_map[create.event_id],
                    chain_map[event.event_id],
                ),
            )

    def test_out_of_order_events(self) -> None:
        """Test that we handle persisting events that we don't have the full
        auth chain for yet (which should only happen for out of band memberships).
        """
        event_factory = self.hs.get_event_builder_factory()
        bob = "@creator:test"
        alice = "@alice:test"
        room_id = "!room:test"

        # Ensure that we have a rooms entry so that we generate the chain index.
        self.get_success(
            self.store.store_room(
                room_id=room_id,
                room_creator_user_id="",
                is_public=True,
                room_version=RoomVersions.V6,
            )
        )

        # First persist the base room.
        create = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Create,
                    "state_key": "",
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "create"},
                },
            ).build(prev_event_ids=[], auth_event_ids=[])
        )

        bob_join = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": bob,
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "bob_join"},
                },
            ).build(prev_event_ids=[], auth_event_ids=[create.event_id])
        )

        power = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.PowerLevels,
                    "state_key": "",
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "power"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id],
            )
        )

        self.persist([create, bob_join, power])

        # Now persist an invite and a couple of memberships out of order.
        alice_invite = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": bob,
                    "room_id": room_id,
                    "content": {"tag": "alice_invite"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, bob_join.event_id, power.event_id],
            )
        )

        alice_join = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": alice,
                    "room_id": room_id,
                    "content": {"tag": "alice_join"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, alice_invite.event_id, power.event_id],
            )
        )

        alice_join2 = self.get_success(
            event_factory.for_room_version(
                RoomVersions.V6,
                {
                    "type": EventTypes.Member,
                    "state_key": alice,
                    "sender": alice,
                    "room_id": room_id,
                    "content": {"tag": "alice_join2"},
                },
            ).build(
                prev_event_ids=[],
                auth_event_ids=[create.event_id, alice_join.event_id, power.event_id],
            )
        )

        self.persist([alice_join])
        self.persist([alice_join2])
        self.persist([alice_invite])

        # The end result should be sane.
        events = [create, bob_join, power, alice_invite, alice_join]

        chain_map, link_map = self.fetch_chains(events)

        expected_links = [
            (bob_join, create),
            (power, bob_join),
            (alice_invite, power),
        ]

        # Check that the expected links and only the expected links have been
        # added.
        event_map = {e.event_id: e for e in events}
        reverse_chain_map = {v: event_map[k] for k, v in chain_map.items()}

        self.maxDiff = None
        self.assertCountEqual(
            expected_links,
            [
                (reverse_chain_map[(s1, s2)], reverse_chain_map[(t1, t2)])
                for s1, s2, t1, t2 in link_map.get_additions()
            ],
        )

    def persist(
        self,
        events: list[EventBase],
    ) -> None:
        """Persist the given events and check that the links generated match
        those given.
        """

        persist_events_store = self.hs.get_datastores().persist_events
        assert persist_events_store is not None

        for e in events:
            e.internal_metadata.stream_ordering = self._next_stream_ordering
            e.internal_metadata.instance_name = self.hs.get_instance_name()
            self._next_stream_ordering += 1

        def _persist(txn: LoggingTransaction) -> None:
            # We need to persist the events to the events and state_events
            # tables.
            assert persist_events_store is not None
            persist_events_store._store_event_txn(
                txn,
                [
                    (e, EventContext(self.hs.get_storage_controllers(), {}))
                    for e in events
                ],
            )

            # Actually call the function that calculates the auth chain stuff.
            new_event_links = (
                persist_events_store.calculate_chain_cover_index_for_events_txn(
                    txn, events[0].room_id, [e for e in events if e.is_state()]
                )
            )
            persist_events_store._persist_event_auth_chain_txn(
                txn, events, new_event_links
            )

        self.get_success(
            persist_events_store.db_pool.runInteraction(
                "_persist",
                _persist,
            )
        )

    def fetch_chains(
        self, events: list[EventBase]
    ) -> tuple[dict[str, tuple[int, int]], _LinkMap]:
        # Fetch the map from event ID -> (chain ID, sequence number)
        rows = cast(
            list[tuple[str, int, int]],
            self.get_success(
                self.store.db_pool.simple_select_many_batch(
                    table="event_auth_chains",
                    column="event_id",
                    iterable=[e.event_id for e in events],
                    retcols=("event_id", "chain_id", "sequence_number"),
                    keyvalues={},
                )
            ),
        )

        chain_map = {
            event_id: (chain_id, sequence_number)
            for event_id, chain_id, sequence_number in rows
        }

        # Fetch all the links and pass them to the _LinkMap.
        auth_chain_rows = cast(
            list[tuple[int, int, int, int]],
            self.get_success(
                self.store.db_pool.simple_select_many_batch(
                    table="event_auth_chain_links",
                    column="origin_chain_id",
                    iterable=[chain_id for chain_id, _ in chain_map.values()],
                    retcols=(
                        "origin_chain_id",
                        "origin_sequence_number",
                        "target_chain_id",
                        "target_sequence_number",
                    ),
                    keyvalues={},
                )
            ),
        )

        link_map = _LinkMap()
        for (
            origin_chain_id,
            origin_sequence_number,
            target_chain_id,
            target_sequence_number,
        ) in auth_chain_rows:
            added = link_map.add_link(
                (origin_chain_id, origin_sequence_number),
                (target_chain_id, target_sequence_number),
            )

            # We shouldn't have persisted any redundant links
            self.assertTrue(added)

        return chain_map, link_map


class LinkMapTestCase(unittest.TestCase):
    def test_simple(self) -> None:
        """Basic tests for the LinkMap."""
        link_map = _LinkMap()

        link_map.add_link((1, 1), (2, 1), new=False)
        self.assertCountEqual(link_map.get_additions(), [])
        self.assertTrue(link_map.exists_path_from((1, 5), (2, 1)))
        self.assertFalse(link_map.exists_path_from((1, 5), (2, 2)))
        self.assertTrue(link_map.exists_path_from((1, 5), (1, 1)))
        self.assertFalse(link_map.exists_path_from((1, 1), (1, 5)))

        # Attempting to add a redundant link is ignored.
        self.assertFalse(link_map.add_link((1, 4), (2, 1)))
        self.assertCountEqual(link_map.get_additions(), [])

        # Adding new non-redundant links works
        self.assertTrue(link_map.add_link((1, 3), (2, 3)))
        self.assertCountEqual(link_map.get_additions(), [(1, 3, 2, 3)])

        self.assertTrue(link_map.add_link((2, 5), (1, 3)))
        self.assertCountEqual(link_map.get_additions(), [(1, 3, 2, 3), (2, 5, 1, 3)])

    def test_exists_path_from(self) -> None:
        "Check that `exists_path_from` can handle non-direct links"
        link_map = _LinkMap()

        link_map.add_link((1, 1), (2, 1), new=False)
        link_map.add_link((2, 1), (3, 1), new=False)

        self.assertTrue(link_map.exists_path_from((1, 4), (3, 1)))
        self.assertFalse(link_map.exists_path_from((1, 4), (3, 2)))

        link_map.add_link((1, 5), (2, 3), new=False)
        link_map.add_link((2, 2), (3, 3), new=False)

        self.assertTrue(link_map.exists_path_from((1, 6), (3, 2)))
        self.assertFalse(link_map.exists_path_from((1, 4), (3, 2)))


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

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.store = hs.get_datastores().main
        self.user_id = self.register_user("foo", "pass")
        self.token = self.login("foo", "pass")
        self.requester = create_requester(self.user_id)

    def _generate_room(self) -> tuple[str, list[set[str]]]:
        """Insert a room without a chain cover index."""
        room_id = self.helper.create_room_as(self.user_id, tok=self.token)

        # Mark the room as not having a chain cover index
        self.get_success(
            self.store.db_pool.simple_update(
                table="rooms",
                keyvalues={"room_id": room_id},
                updatevalues={"has_auth_chain_index": False},
                desc="test",
            )
        )

        # Create a fork in the DAG with different events.
        event_handler = self.hs.get_event_creation_handler()
        latest_event_ids = self.get_success(
            self.store.get_prev_events_for_room(room_id)
        )
        event, unpersisted_context = self.get_success(
            event_handler.create_event(
                self.requester,
                {
                    "type": "some_state_type",
                    "state_key": "",
                    "content": {},
                    "room_id": room_id,
                    "sender": self.user_id,
                },
                prev_event_ids=latest_event_ids,
            )
        )
        context = self.get_success(unpersisted_context.persist(event))
        self.get_success(
            event_handler.handle_new_client_event(
                self.requester, events_and_context=[(event, context)]
            )
        )
        state_ids1 = self.get_success(context.get_current_state_ids())
        assert state_ids1 is not None
        state1 = set(state_ids1.values())

        event, unpersisted_context = self.get_success(
            event_handler.create_event(
                self.requester,
                {
                    "type": "some_state_type",
                    "state_key": "",
                    "content": {},
                    "room_id": room_id,
                    "sender": self.user_id,
                },
                prev_event_ids=latest_event_ids,
            )
        )
        context = self.get_success(unpersisted_context.persist(event))
        self.get_success(
            event_handler.handle_new_client_event(
                self.requester, events_and_context=[(event, context)]
            )
        )
        state_ids2 = self.get_success(context.get_current_state_ids())
        assert state_ids2 is not None
        state2 = set(state_ids2.values())

        # Delete the chain cover info.

        def _delete_tables(txn: Cursor) -> None:
            txn.execute("DELETE FROM event_auth_chains")
            txn.execute("DELETE FROM event_auth_chain_links")

        self.get_success(self.store.db_pool.runInteraction("test", _delete_tables))

        return room_id, [state1, state2]

    def test_background_update_single_room(self) -> None:
        """Test that the background update to calculate auth chains for historic
        rooms works correctly.
        """

        # Create a room
        room_id, states = self._generate_room()

        # Insert and run the background update.
        self.get_success(
            self.store.db_pool.simple_insert(
                "background_updates",
                {"update_name": "chain_cover", "progress_json": "{}"},
            )
        )

        # Ugh, have to reset this flag
        self.store.db_pool.updates._all_done = False

        self.wait_for_background_updates()

        # Test that the `has_auth_chain_index` has been set
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id)))

        # Test that calculating the auth chain difference using the newly
        # calculated chain cover works.
        self.get_success(
            self.store.db_pool.runInteraction(
                "test",
                self.store._get_auth_chain_difference_using_cover_index_txn,
                room_id,
                states,
            )
        )

    def test_background_update_multiple_rooms(self) -> None:
        """Test that the background update to calculate auth chains for historic
        rooms works correctly.
        """
        # Create a room
        room_id1, states1 = self._generate_room()
        room_id2, states2 = self._generate_room()
        room_id3, states2 = self._generate_room()

        # Insert and run the background update.
        self.get_success(
            self.store.db_pool.simple_insert(
                "background_updates",
                {"update_name": "chain_cover", "progress_json": "{}"},
            )
        )

        # Ugh, have to reset this flag
        self.store.db_pool.updates._all_done = False

        self.wait_for_background_updates()

        # Test that the `has_auth_chain_index` has been set
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id1)))
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id2)))
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id3)))

        # Test that calculating the auth chain difference using the newly
        # calculated chain cover works.
        self.get_success(
            self.store.db_pool.runInteraction(
                "test",
                self.store._get_auth_chain_difference_using_cover_index_txn,
                room_id1,
                states1,
            )
        )

    def test_background_update_single_large_room(self) -> None:
        """Test that the background update to calculate auth chains for historic
        rooms works correctly.
        """

        # Create a room
        room_id, states = self._generate_room()

        # Add a bunch of state so that it takes multiple iterations of the
        # background update to process the room.
        for i in range(150):
            self.helper.send_state(
                room_id, event_type="m.test", body={"index": i}, tok=self.token
            )

        # Insert and run the background update.
        self.get_success(
            self.store.db_pool.simple_insert(
                "background_updates",
                {"update_name": "chain_cover", "progress_json": "{}"},
            )
        )

        # Ugh, have to reset this flag
        self.store.db_pool.updates._all_done = False

        iterations = 0
        while not self.get_success(
            self.store.db_pool.updates.has_completed_background_updates()
        ):
            iterations += 1
            self.get_success(
                self.store.db_pool.updates.do_next_background_update(False), by=0.1
            )

        # Ensure that we did actually take multiple iterations to process the
        # room.
        self.assertGreater(iterations, 1)

        # Test that the `has_auth_chain_index` has been set
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id)))

        # Test that calculating the auth chain difference using the newly
        # calculated chain cover works.
        self.get_success(
            self.store.db_pool.runInteraction(
                "test",
                self.store._get_auth_chain_difference_using_cover_index_txn,
                room_id,
                states,
            )
        )

    def test_background_update_multiple_large_room(self) -> None:
        """Test that the background update to calculate auth chains for historic
        rooms works correctly.
        """

        # Create the rooms
        room_id1, _ = self._generate_room()
        room_id2, _ = self._generate_room()

        # Add a bunch of state so that it takes multiple iterations of the
        # background update to process the room.
        for i in range(150):
            self.helper.send_state(
                room_id1, event_type="m.test", body={"index": i}, tok=self.token
            )

        for i in range(150):
            self.helper.send_state(
                room_id2, event_type="m.test", body={"index": i}, tok=self.token
            )

        # Insert and run the background update.
        self.get_success(
            self.store.db_pool.simple_insert(
                "background_updates",
                {"update_name": "chain_cover", "progress_json": "{}"},
            )
        )

        # Ugh, have to reset this flag
        self.store.db_pool.updates._all_done = False

        iterations = 0
        while not self.get_success(
            self.store.db_pool.updates.has_completed_background_updates()
        ):
            iterations += 1
            self.get_success(
                self.store.db_pool.updates.do_next_background_update(False), by=0.1
            )

        # Ensure that we did actually take multiple iterations to process the
        # room.
        self.assertGreater(iterations, 1)

        # Test that the `has_auth_chain_index` has been set
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id1)))
        self.assertTrue(self.get_success(self.store.has_auth_chain_index(room_id2)))
