#
# 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]
#
#

"""Tests for the password_auth_provider interface"""

from http import HTTPStatus
from typing import Any
from unittest.mock import AsyncMock, Mock

from twisted.internet.testing import MemoryReactor

import synapse
from synapse.api.constants import LoginType
from synapse.api.errors import Codes
from synapse.handlers.account import AccountHandler
from synapse.module_api import ModuleApi
from synapse.rest.client import account, devices, login, logout, register
from synapse.server import HomeServer
from synapse.types import JsonDict, UserID
from synapse.util.clock import Clock

from tests import unittest
from tests.server import FakeChannel
from tests.unittest import override_config

# Login flows we expect to appear in the list after the normal ones.
ADDITIONAL_LOGIN_FLOWS = [
    {"type": "m.login.application_service"},
]

# a mock instance which the dummy auth providers delegate to, so we can see what's going
# on
mock_password_provider = Mock()


class LegacyPasswordOnlyAuthProvider:
    """A legacy password_provider which only implements `check_password`."""

    @staticmethod
    def parse_config(config: JsonDict) -> None:
        pass

    def __init__(self, config: None, account_handler: AccountHandler):
        pass

    def check_password(self, *args: str) -> Mock:
        return mock_password_provider.check_password(*args)


class LegacyCustomAuthProvider:
    """A legacy password_provider which implements a custom login type."""

    @staticmethod
    def parse_config(config: JsonDict) -> None:
        pass

    def __init__(self, config: None, account_handler: AccountHandler):
        pass

    def get_supported_login_types(self) -> dict[str, list[str]]:
        return {"test.login_type": ["test_field"]}

    def check_auth(self, *args: str) -> Mock:
        return mock_password_provider.check_auth(*args)


class CustomAuthProvider:
    """A module which registers password_auth_provider callbacks for a custom login type."""

    @staticmethod
    def parse_config(config: JsonDict) -> None:
        pass

    def __init__(self, config: None, api: ModuleApi):
        api.register_password_auth_provider_callbacks(
            auth_checkers={("test.login_type", ("test_field",)): self.check_auth}
        )

    def check_auth(self, *args: Any) -> Mock:
        return mock_password_provider.check_auth(*args)


class LegacyPasswordCustomAuthProvider:
    """A password_provider which implements password login via `check_auth`, as well
    as a custom type."""

    @staticmethod
    def parse_config(config: JsonDict) -> None:
        pass

    def __init__(self, config: None, account_handler: AccountHandler):
        pass

    def get_supported_login_types(self) -> dict[str, list[str]]:
        return {"m.login.password": ["password"], "test.login_type": ["test_field"]}

    def check_auth(self, *args: str) -> Mock:
        return mock_password_provider.check_auth(*args)


class PasswordCustomAuthProvider:
    """A module which registers password_auth_provider callbacks for a custom login type.
    as well as a password login"""

    @staticmethod
    def parse_config(config: JsonDict) -> None:
        pass

    def __init__(self, config: None, api: ModuleApi):
        api.register_password_auth_provider_callbacks(
            auth_checkers={
                ("test.login_type", ("test_field",)): self.check_auth,
                ("m.login.password", ("password",)): self.check_auth,
            }
        )

    def check_auth(self, *args: Any) -> Mock:
        return mock_password_provider.check_auth(*args)

    def check_pass(self, *args: str) -> Mock:
        return mock_password_provider.check_password(*args)


def legacy_providers_config(*providers: type[Any]) -> dict:
    """Returns a config dict that will enable the given legacy password auth providers"""
    return {
        "password_providers": [
            {"module": "%s.%s" % (__name__, provider.__qualname__), "config": {}}
            for provider in providers
        ]
    }


def providers_config(*providers: type[Any]) -> dict:
    """Returns a config dict that will enable the given modules"""
    return {
        "modules": [
            {"module": "%s.%s" % (__name__, provider.__qualname__), "config": {}}
            for provider in providers
        ]
    }


class PasswordAuthProviderTests(unittest.HomeserverTestCase):
    servlets = [
        synapse.rest.admin.register_servlets,
        login.register_servlets,
        devices.register_servlets,
        logout.register_servlets,
        register.register_servlets,
        account.register_servlets,
    ]

    CALLBACK_USERNAME = "get_username_for_registration"
    CALLBACK_DISPLAYNAME = "get_displayname_for_registration"

    def prepare(
        self, reactor: MemoryReactor, clock: Clock, homeserver: HomeServer
    ) -> None:
        # we use a global mock device, so make sure we are starting with a clean slate
        mock_password_provider.reset_mock()

        # The mock password provider doesn't register the users, so ensure they
        # are registered first.
        self.register_user("u", "not-the-tested-password")
        self.register_user("user", "not-the-tested-password")

    @override_config(legacy_providers_config(LegacyPasswordOnlyAuthProvider))
    def test_password_only_auth_progiver_login_legacy(self) -> None:
        self.password_only_auth_provider_login_test_body()

    def password_only_auth_provider_login_test_body(self) -> None:
        # login flows should only have m.login.password
        flows = self._get_login_flows()
        self.assertEqual(flows, [{"type": "m.login.password"}] + ADDITIONAL_LOGIN_FLOWS)

        # check_password must return an awaitable
        mock_password_provider.check_password = AsyncMock(return_value=True)
        channel = self._send_password_login("u", "p")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual("@u:test", channel.json_body["user_id"])
        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
        mock_password_provider.reset_mock()

        # login with mxid should work too
        channel = self._send_password_login("@u:test", "p")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual("@u:test", channel.json_body["user_id"])
        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
        mock_password_provider.reset_mock()

    @override_config(legacy_providers_config(LegacyPasswordOnlyAuthProvider))
    def test_password_only_auth_provider_ui_auth_legacy(self) -> None:
        self.password_only_auth_provider_ui_auth_test_body()

    def password_only_auth_provider_ui_auth_test_body(self) -> None:
        """UI Auth should delegate correctly to the password provider"""

        # log in twice, to get two devices
        mock_password_provider.check_password = AsyncMock(return_value=True)
        tok1 = self.login("u", "p")
        self.login("u", "p", device_id="dev2")
        mock_password_provider.reset_mock()

        # have the auth provider deny the request to start with
        mock_password_provider.check_password = AsyncMock(return_value=False)

        # make the initial request which returns a 401
        session = self._start_delete_device_session(tok1, "dev2")
        mock_password_provider.check_password.assert_not_called()

        # Make another request providing the UI auth flow.
        channel = self._authed_delete_device(tok1, "dev2", session, "u", "p")
        self.assertEqual(channel.code, 401)  # XXX why not a 403?
        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
        mock_password_provider.reset_mock()

        # Finally, check the request goes through when we allow it
        mock_password_provider.check_password = AsyncMock(return_value=True)
        channel = self._authed_delete_device(tok1, "dev2", session, "u", "p")
        self.assertEqual(channel.code, 200)
        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")

    @override_config(legacy_providers_config(LegacyPasswordOnlyAuthProvider))
    def test_local_user_fallback_login_legacy(self) -> None:
        self.local_user_fallback_login_test_body()

    def local_user_fallback_login_test_body(self) -> None:
        """rejected login should fall back to local db"""
        self.register_user("localuser", "localpass")

        # check_password must return an awaitable
        mock_password_provider.check_password = AsyncMock(return_value=False)
        channel = self._send_password_login("u", "p")
        self.assertEqual(channel.code, HTTPStatus.FORBIDDEN, channel.result)

        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual("@localuser:test", channel.json_body["user_id"])

    @override_config(legacy_providers_config(LegacyPasswordOnlyAuthProvider))
    def test_local_user_fallback_ui_auth_legacy(self) -> None:
        self.local_user_fallback_ui_auth_test_body()

    def local_user_fallback_ui_auth_test_body(self) -> None:
        """rejected login should fall back to local db"""
        self.register_user("localuser", "localpass")

        # have the auth provider deny the request
        mock_password_provider.check_password = AsyncMock(return_value=False)

        # log in twice, to get two devices
        tok1 = self.login("localuser", "localpass")
        self.login("localuser", "localpass", device_id="dev2")
        mock_password_provider.check_password.reset_mock()

        # first delete should give a 401
        session = self._start_delete_device_session(tok1, "dev2")
        mock_password_provider.check_password.assert_not_called()

        # Wrong password
        channel = self._authed_delete_device(tok1, "dev2", session, "localuser", "xxx")
        self.assertEqual(channel.code, 401)  # XXX why not a 403?
        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
        mock_password_provider.check_password.assert_called_once_with(
            "@localuser:test", "xxx"
        )
        mock_password_provider.reset_mock()

        # Right password
        channel = self._authed_delete_device(
            tok1, "dev2", session, "localuser", "localpass"
        )
        self.assertEqual(channel.code, 200)
        mock_password_provider.check_password.assert_called_once_with(
            "@localuser:test", "localpass"
        )

    @override_config(
        {
            **legacy_providers_config(LegacyPasswordOnlyAuthProvider),
            "password_config": {"localdb_enabled": False},
        }
    )
    def test_no_local_user_fallback_login_legacy(self) -> None:
        self.no_local_user_fallback_login_test_body()

    def no_local_user_fallback_login_test_body(self) -> None:
        """localdb_enabled can block login with the local password"""
        self.register_user("localuser", "localpass")

        # check_password must return an awaitable
        mock_password_provider.check_password = AsyncMock(return_value=False)
        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, 403)
        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
        mock_password_provider.check_password.assert_called_once_with(
            "@localuser:test", "localpass"
        )

    @override_config(
        {
            **legacy_providers_config(LegacyPasswordOnlyAuthProvider),
            "password_config": {"localdb_enabled": False},
        }
    )
    def test_no_local_user_fallback_ui_auth_legacy(self) -> None:
        self.no_local_user_fallback_ui_auth_test_body()

    def no_local_user_fallback_ui_auth_test_body(self) -> None:
        """localdb_enabled can block ui auth with the local password"""
        self.register_user("localuser", "localpass")

        # allow login via the auth provider
        mock_password_provider.check_password = AsyncMock(return_value=True)

        # log in twice, to get two devices
        tok1 = self.login("localuser", "p")
        self.login("localuser", "p", device_id="dev2")
        mock_password_provider.check_password.reset_mock()

        # first delete should give a 401
        channel = self._delete_device(tok1, "dev2")
        self.assertEqual(channel.code, 401)
        # m.login.password UIA is permitted because the auth provider allows it,
        # even though the localdb does not.
        self.assertEqual(channel.json_body["flows"], [{"stages": ["m.login.password"]}])
        session = channel.json_body["session"]
        mock_password_provider.check_password.assert_not_called()

        # now try deleting with the local password
        mock_password_provider.check_password = AsyncMock(return_value=False)
        channel = self._authed_delete_device(
            tok1, "dev2", session, "localuser", "localpass"
        )
        self.assertEqual(channel.code, 401)  # XXX why not a 403?
        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
        mock_password_provider.check_password.assert_called_once_with(
            "@localuser:test", "localpass"
        )

    @override_config(
        {
            **legacy_providers_config(LegacyPasswordOnlyAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_password_auth_disabled_legacy(self) -> None:
        self.password_auth_disabled_test_body()

    def password_auth_disabled_test_body(self) -> None:
        """password auth doesn't work if it's disabled across the board"""
        # login flows should be empty
        flows = self._get_login_flows()
        self.assertEqual(flows, ADDITIONAL_LOGIN_FLOWS)

        # login shouldn't work and should be rejected with a 400 ("unknown login type")
        channel = self._send_password_login("u", "p")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        mock_password_provider.check_password.assert_not_called()

    @override_config(legacy_providers_config(LegacyCustomAuthProvider))
    def test_custom_auth_provider_login_legacy(self) -> None:
        self.custom_auth_provider_login_test_body()

    @override_config(providers_config(CustomAuthProvider))
    def test_custom_auth_provider_login(self) -> None:
        self.custom_auth_provider_login_test_body()

    def custom_auth_provider_login_test_body(self) -> None:
        # login flows should have the custom flow and m.login.password, since we
        # haven't disabled local password lookup.
        # (password must come first, because reasons)
        flows = self._get_login_flows()
        self.assertEqual(
            flows,
            [{"type": "m.login.password"}, {"type": "test.login_type"}]
            + ADDITIONAL_LOGIN_FLOWS,
        )

        # login with missing param should be rejected
        channel = self._send_login("test.login_type", "u")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        mock_password_provider.check_auth.assert_not_called()

        mock_password_provider.check_auth = AsyncMock(return_value=("@user:test", None))
        channel = self._send_login("test.login_type", "u", test_field="y")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual("@user:test", channel.json_body["user_id"])
        mock_password_provider.check_auth.assert_called_once_with(
            "u", "test.login_type", {"test_field": "y"}
        )
        mock_password_provider.reset_mock()

    @override_config(legacy_providers_config(LegacyCustomAuthProvider))
    def test_custom_auth_provider_ui_auth_legacy(self) -> None:
        self.custom_auth_provider_ui_auth_test_body()

    @override_config(providers_config(CustomAuthProvider))
    def test_custom_auth_provider_ui_auth(self) -> None:
        self.custom_auth_provider_ui_auth_test_body()

    def custom_auth_provider_ui_auth_test_body(self) -> None:
        # register the user and log in twice, to get two devices
        self.register_user("localuser", "localpass")
        tok1 = self.login("localuser", "localpass")
        self.login("localuser", "localpass", device_id="dev2")

        # make the initial request which returns a 401
        channel = self._delete_device(tok1, "dev2")
        self.assertEqual(channel.code, 401)
        # Ensure that flows are what is expected.
        self.assertIn({"stages": ["m.login.password"]}, channel.json_body["flows"])
        self.assertIn({"stages": ["test.login_type"]}, channel.json_body["flows"])
        session = channel.json_body["session"]

        # missing param
        body = {
            "auth": {
                "type": "test.login_type",
                "identifier": {"type": "m.id.user", "user": "localuser"},
                "session": session,
            },
        }

        channel = self._delete_device(tok1, "dev2", body)
        self.assertEqual(channel.code, 400)
        # there's a perfectly good M_MISSING_PARAM errcode, but heaven forfend we should
        # use it...
        self.assertIn("Missing parameters", channel.json_body["error"])
        mock_password_provider.check_auth.assert_not_called()
        mock_password_provider.reset_mock()

        # right params, but authing as the wrong user
        mock_password_provider.check_auth = AsyncMock(return_value=("@user:test", None))
        body["auth"]["test_field"] = "foo"
        channel = self._delete_device(tok1, "dev2", body)
        self.assertEqual(channel.code, 403)
        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
        mock_password_provider.check_auth.assert_called_once_with(
            "localuser", "test.login_type", {"test_field": "foo"}
        )
        mock_password_provider.reset_mock()

        # and finally, succeed
        mock_password_provider.check_auth = AsyncMock(
            return_value=("@localuser:test", None)
        )
        channel = self._delete_device(tok1, "dev2", body)
        self.assertEqual(channel.code, 200)
        mock_password_provider.check_auth.assert_called_once_with(
            "localuser", "test.login_type", {"test_field": "foo"}
        )

    @override_config(legacy_providers_config(LegacyCustomAuthProvider))
    def test_custom_auth_provider_callback_legacy(self) -> None:
        self.custom_auth_provider_callback_test_body()

    @override_config(providers_config(CustomAuthProvider))
    def test_custom_auth_provider_callback(self) -> None:
        self.custom_auth_provider_callback_test_body()

    def custom_auth_provider_callback_test_body(self) -> None:
        callback = AsyncMock(return_value=None)

        mock_password_provider.check_auth = AsyncMock(
            return_value=("@user:test", callback)
        )
        channel = self._send_login("test.login_type", "u", test_field="y")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual("@user:test", channel.json_body["user_id"])
        mock_password_provider.check_auth.assert_called_once_with(
            "u", "test.login_type", {"test_field": "y"}
        )

        # check the args to the callback
        callback.assert_called_once()
        call_args, call_kwargs = callback.call_args
        # should be one positional arg
        self.assertEqual(len(call_args), 1)
        self.assertEqual(call_args[0]["user_id"], "@user:test")
        for p in ["user_id", "access_token", "device_id", "home_server"]:
            self.assertIn(p, call_args[0])

    @override_config(
        {
            **legacy_providers_config(LegacyCustomAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_custom_auth_password_disabled_legacy(self) -> None:
        self.custom_auth_password_disabled_test_body()

    @override_config(
        {**providers_config(CustomAuthProvider), "password_config": {"enabled": False}}
    )
    def test_custom_auth_password_disabled(self) -> None:
        self.custom_auth_password_disabled_test_body()

    def custom_auth_password_disabled_test_body(self) -> None:
        """Test login with a custom auth provider where password login is disabled"""
        self.register_user("localuser", "localpass")

        flows = self._get_login_flows()
        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)

        # login shouldn't work and should be rejected with a 400 ("unknown login type")
        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        mock_password_provider.check_auth.assert_not_called()

    @override_config(
        {
            **legacy_providers_config(LegacyCustomAuthProvider),
            "password_config": {"enabled": False, "localdb_enabled": False},
        }
    )
    def test_custom_auth_password_disabled_localdb_enabled_legacy(self) -> None:
        self.custom_auth_password_disabled_localdb_enabled_test_body()

    @override_config(
        {
            **providers_config(CustomAuthProvider),
            "password_config": {"enabled": False, "localdb_enabled": False},
        }
    )
    def test_custom_auth_password_disabled_localdb_enabled(self) -> None:
        self.custom_auth_password_disabled_localdb_enabled_test_body()

    def custom_auth_password_disabled_localdb_enabled_test_body(self) -> None:
        """Check the localdb_enabled == enabled == False

        Regression test for https://github.com/matrix-org/synapse/issues/8914: check
        that setting *both* `localdb_enabled` *and* `password: enabled` to False doesn't
        cause an exception.
        """
        self.register_user("localuser", "localpass")

        flows = self._get_login_flows()
        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)

        # login shouldn't work and should be rejected with a 400 ("unknown login type")
        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        mock_password_provider.check_auth.assert_not_called()

    @override_config(
        {
            **legacy_providers_config(LegacyPasswordCustomAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_password_custom_auth_password_disabled_login_legacy(self) -> None:
        self.password_custom_auth_password_disabled_login_test_body()

    @override_config(
        {
            **providers_config(PasswordCustomAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_password_custom_auth_password_disabled_login(self) -> None:
        self.password_custom_auth_password_disabled_login_test_body()

    def password_custom_auth_password_disabled_login_test_body(self) -> None:
        """log in with a custom auth provider which implements password, but password
        login is disabled"""
        self.register_user("localuser", "localpass")

        flows = self._get_login_flows()
        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)

        # login shouldn't work and should be rejected with a 400 ("unknown login type")
        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        mock_password_provider.check_auth.assert_not_called()
        mock_password_provider.check_password.assert_not_called()

    @override_config(
        {
            **legacy_providers_config(LegacyPasswordCustomAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_password_custom_auth_password_disabled_ui_auth_legacy(self) -> None:
        self.password_custom_auth_password_disabled_ui_auth_test_body()

    @override_config(
        {
            **providers_config(PasswordCustomAuthProvider),
            "password_config": {"enabled": False},
        }
    )
    def test_password_custom_auth_password_disabled_ui_auth(self) -> None:
        self.password_custom_auth_password_disabled_ui_auth_test_body()

    def password_custom_auth_password_disabled_ui_auth_test_body(self) -> None:
        """UI Auth with a custom auth provider which implements password, but password
        login is disabled"""
        # register the user and log in twice via the test login type to get two devices,
        self.register_user("localuser", "localpass")
        mock_password_provider.check_auth = AsyncMock(
            return_value=("@localuser:test", None)
        )
        channel = self._send_login("test.login_type", "localuser", test_field="")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        tok1 = channel.json_body["access_token"]

        channel = self._send_login(
            "test.login_type", "localuser", test_field="", device_id="dev2"
        )
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)

        # make the initial request which returns a 401
        channel = self._delete_device(tok1, "dev2")
        self.assertEqual(channel.code, 401)
        # Ensure that flows are what is expected. In particular, "password" should *not*
        # be present.
        self.assertIn({"stages": ["test.login_type"]}, channel.json_body["flows"])
        session = channel.json_body["session"]

        mock_password_provider.reset_mock()

        # check that auth with password is rejected
        body = {
            "auth": {
                "type": "m.login.password",
                "identifier": {"type": "m.id.user", "user": "localuser"},
                "password": "localpass",
                "session": session,
            },
        }

        channel = self._delete_device(tok1, "dev2", body)
        self.assertEqual(channel.code, 400)
        self.assertEqual(
            "Password login has been disabled.", channel.json_body["error"]
        )
        mock_password_provider.check_auth.assert_not_called()
        mock_password_provider.check_password.assert_not_called()
        mock_password_provider.reset_mock()

        # successful auth
        body["auth"]["type"] = "test.login_type"
        body["auth"]["test_field"] = "x"
        channel = self._delete_device(tok1, "dev2", body)
        self.assertEqual(channel.code, 200)
        mock_password_provider.check_auth.assert_called_once_with(
            "localuser", "test.login_type", {"test_field": "x"}
        )
        mock_password_provider.check_password.assert_not_called()

    @override_config(
        {
            **legacy_providers_config(LegacyCustomAuthProvider),
            "password_config": {"localdb_enabled": False},
        }
    )
    def test_custom_auth_no_local_user_fallback_legacy(self) -> None:
        self.custom_auth_no_local_user_fallback_test_body()

    @override_config(
        {
            **providers_config(CustomAuthProvider),
            "password_config": {"localdb_enabled": False},
        }
    )
    def test_custom_auth_no_local_user_fallback(self) -> None:
        self.custom_auth_no_local_user_fallback_test_body()

    def custom_auth_no_local_user_fallback_test_body(self) -> None:
        """Test login with a custom auth provider where the local db is disabled"""
        self.register_user("localuser", "localpass")

        flows = self._get_login_flows()
        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)

        # password login shouldn't work and should be rejected with a 400
        # ("unknown login type")
        channel = self._send_password_login("localuser", "localpass")
        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)

    def test_on_logged_out(self) -> None:
        """Tests that the on_logged_out callback is called when the user logs out."""
        self.register_user("rin", "password")
        tok = self.login("rin", "password")

        self.called = False

        async def on_logged_out(
            user_id: str, device_id: str | None, access_token: str
        ) -> None:
            self.called = True

        on_logged_out = Mock(side_effect=on_logged_out)
        self.hs.get_password_auth_provider().on_logged_out_callbacks.append(
            on_logged_out
        )

        channel = self.make_request(
            "POST",
            "/_matrix/client/v3/logout",
            {},
            access_token=tok,
        )
        self.assertEqual(channel.code, 200)
        on_logged_out.assert_called_once()
        self.assertTrue(self.called)

    def test_username(self) -> None:
        """Tests that the get_username_for_registration callback can define the username
        of a user when registering.
        """
        self._setup_get_name_for_registration(
            callback_name=self.CALLBACK_USERNAME,
        )

        username = "rin"
        channel = self.make_request(
            "POST",
            "/register",
            {
                "username": username,
                "password": "bar",
                "auth": {"type": LoginType.DUMMY},
            },
        )
        self.assertEqual(channel.code, 200)

        # Our callback takes the username and appends "-foo" to it, check that's what we
        # have.
        mxid = channel.json_body["user_id"]
        self.assertEqual(UserID.from_string(mxid).localpart, username + "-foo")

    def test_username_uia(self) -> None:
        """Tests that the get_username_for_registration callback is only called at the
        end of the UIA flow.
        """
        m = self._setup_get_name_for_registration(
            callback_name=self.CALLBACK_USERNAME,
        )

        username = "rin"
        res = self._do_uia_assert_mock_not_called(username, m)

        mxid = res["user_id"]
        self.assertEqual(UserID.from_string(mxid).localpart, username + "-foo")

        # Check that the callback has been called.
        m.assert_called_once()

    # Set some email configuration so the test doesn't fail because of its absence.
    @override_config({"email": {"notif_from": "noreply@test"}})
    def test_3pid_allowed(self) -> None:
        """Tests that an is_3pid_allowed_callbacks forbidding a 3PID makes Synapse refuse
        to bind the new 3PID, and that one allowing a 3PID makes Synapse accept to bind
        the 3PID. Also checks that the module is passed a boolean indicating whether the
        user to bind this 3PID to is currently registering.
        """
        self._test_3pid_allowed("rin", False)
        self._test_3pid_allowed("kitay", True)

    def test_displayname(self) -> None:
        """Tests that the get_displayname_for_registration callback can define the
        display name of a user when registering.
        """
        self._setup_get_name_for_registration(
            callback_name=self.CALLBACK_DISPLAYNAME,
        )

        username = "rin"
        channel = self.make_request(
            "POST",
            "/register",
            {
                "username": username,
                "password": "bar",
                "auth": {"type": LoginType.DUMMY},
            },
        )
        self.assertEqual(channel.code, 200)

        # Our callback takes the username and appends "-foo" to it, check that's what we
        # have.
        user_id = UserID.from_string(channel.json_body["user_id"])
        display_name = self.get_success(
            self.hs.get_profile_handler().get_displayname(user_id)
        )

        self.assertEqual(display_name, username + "-foo")

    def test_displayname_uia(self) -> None:
        """Tests that the get_displayname_for_registration callback is only called at the
        end of the UIA flow.
        """
        m = self._setup_get_name_for_registration(
            callback_name=self.CALLBACK_DISPLAYNAME,
        )

        username = "rin"
        res = self._do_uia_assert_mock_not_called(username, m)

        user_id = UserID.from_string(res["user_id"])
        display_name = self.get_success(
            self.hs.get_profile_handler().get_displayname(user_id)
        )

        self.assertEqual(display_name, username + "-foo")

        # Check that the callback has been called.
        m.assert_called_once()

    def _test_3pid_allowed(self, username: str, registration: bool) -> None:
        """Tests that the "is_3pid_allowed" module callback is called correctly, using
        either /register or /account URLs depending on the arguments.

        Args:
            username: The username to use for the test.
            registration: Whether to test with registration URLs.
        """
        self.hs.get_identity_handler().send_threepid_validation = AsyncMock(  # type: ignore[method-assign]
            return_value=0
        )

        m = AsyncMock(return_value=False)
        self.hs.get_password_auth_provider().is_3pid_allowed_callbacks = [m]

        self.register_user(username, "password")
        tok = self.login(username, "password")

        if registration:
            url = "/register/email/requestToken"
        else:
            url = "/account/3pid/email/requestToken"

        channel = self.make_request(
            "POST",
            url,
            {
                "client_secret": "foo",
                "email": "foo@test.com",
                "send_attempt": 0,
            },
            access_token=tok,
        )
        self.assertEqual(channel.code, HTTPStatus.FORBIDDEN, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.THREEPID_DENIED,
            channel.json_body,
        )

        m.assert_called_once_with("email", "foo@test.com", registration)

        m = AsyncMock(return_value=True)
        self.hs.get_password_auth_provider().is_3pid_allowed_callbacks = [m]

        channel = self.make_request(
            "POST",
            url,
            {
                "client_secret": "foo",
                "email": "bar@test.com",
                "send_attempt": 0,
            },
            access_token=tok,
        )
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertIn("sid", channel.json_body)

        m.assert_called_once_with("email", "bar@test.com", registration)

    def _setup_get_name_for_registration(self, callback_name: str) -> Mock:
        """Registers either a get_username_for_registration callback or a
        get_displayname_for_registration callback that appends "-foo" to the username the
        client is trying to register.
        """

        async def callback(uia_results: JsonDict, params: JsonDict) -> str:
            self.assertIn(LoginType.DUMMY, uia_results)
            username = params["username"]
            return username + "-foo"

        m = Mock(side_effect=callback)

        password_auth_provider = self.hs.get_password_auth_provider()
        getattr(password_auth_provider, callback_name + "_callbacks").append(m)

        return m

    def _do_uia_assert_mock_not_called(self, username: str, m: Mock) -> JsonDict:
        # Initiate the UIA flow.
        channel = self.make_request(
            "POST",
            "register",
            {"username": username, "type": "m.login.password", "password": "bar"},
        )
        self.assertEqual(channel.code, 401)
        self.assertIn("session", channel.json_body)

        # Check that the callback hasn't been called yet.
        m.assert_not_called()

        # Finish the UIA flow.
        session = channel.json_body["session"]
        channel = self.make_request(
            "POST",
            "register",
            {"auth": {"session": session, "type": LoginType.DUMMY}},
        )
        self.assertEqual(channel.code, HTTPStatus.OK, channel.json_body)
        return channel.json_body

    def _get_login_flows(self) -> JsonDict:
        channel = self.make_request("GET", "/_matrix/client/r0/login")
        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        return channel.json_body["flows"]

    def _send_password_login(self, user: str, password: str) -> FakeChannel:
        return self._send_login(type="m.login.password", user=user, password=password)

    def _send_login(self, type: str, user: str, **extra_params: str) -> FakeChannel:
        params = {"identifier": {"type": "m.id.user", "user": user}, "type": type}
        params.update(extra_params)
        channel = self.make_request("POST", "/_matrix/client/r0/login", params)
        return channel

    def _start_delete_device_session(self, access_token: str, device_id: str) -> str:
        """Make an initial delete device request, and return the UI Auth session ID"""
        channel = self._delete_device(access_token, device_id)
        self.assertEqual(channel.code, 401)
        # Ensure that flows are what is expected.
        self.assertIn({"stages": ["m.login.password"]}, channel.json_body["flows"])
        return channel.json_body["session"]

    def _authed_delete_device(
        self,
        access_token: str,
        device_id: str,
        session: str,
        user_id: str,
        password: str,
    ) -> FakeChannel:
        """Make a delete device request, authenticating with the given uid/password"""
        return self._delete_device(
            access_token,
            device_id,
            {
                "auth": {
                    "type": "m.login.password",
                    "identifier": {"type": "m.id.user", "user": user_id},
                    "password": password,
                    "session": session,
                },
            },
        )

    def _delete_device(
        self,
        access_token: str,
        device: str,
        body: JsonDict | bytes = b"",
    ) -> FakeChannel:
        """Delete an individual device."""
        channel = self.make_request(
            "DELETE", "devices/" + device, body, access_token=access_token
        )
        return channel
