#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2015, 2016 OpenMarket Ltd
# 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 Optional
from unittest.mock import AsyncMock

import pymacaroons

from twisted.internet.testing import MemoryReactor

from synapse.api.errors import AuthError, ResourceLimitError
from synapse.rest import admin
from synapse.rest.client import login
from synapse.server import HomeServer
from synapse.util.clock import Clock

from tests import unittest


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

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.auth_handler = hs.get_auth_handler()
        self.macaroon_generator = hs.get_macaroon_generator()

        # MAU tests
        # AuthBlocking reads from the hs' config on initialization. We need to
        # modify its config instead of the hs'
        self.auth_blocking = hs.get_auth_blocking()
        self.auth_blocking._max_mau_value = 50

        self.small_number_of_users = 1
        self.large_number_of_users = 100

        self.user1 = self.register_user("a_user", "pass")

    def token_login(self, token: str) -> Optional[str]:
        body = {
            "type": "m.login.token",
            "token": token,
        }

        channel = self.make_request(
            "POST",
            "/_matrix/client/v3/login",
            body,
        )

        if channel.code == 200:
            return channel.json_body["user_id"]

        return None

    def test_macaroon_caveats(self) -> None:
        token = self.macaroon_generator.generate_guest_access_token("a_user")
        macaroon = pymacaroons.Macaroon.deserialize(token)

        def verify_gen(caveat: str) -> bool:
            return caveat == "gen = 1"

        def verify_user(caveat: str) -> bool:
            return caveat == "user_id = a_user"

        def verify_type(caveat: str) -> bool:
            return caveat == "type = access"

        def verify_nonce(caveat: str) -> bool:
            return caveat.startswith("nonce =")

        def verify_guest(caveat: str) -> bool:
            return caveat == "guest = true"

        v = pymacaroons.Verifier()
        v.satisfy_general(verify_gen)
        v.satisfy_general(verify_user)
        v.satisfy_general(verify_type)
        v.satisfy_general(verify_nonce)
        v.satisfy_general(verify_guest)
        v.verify(macaroon, self.hs.config.key.macaroon_secret_key)

    def test_login_token_gives_user_id(self) -> None:
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(
                self.user1,
                duration_ms=(5 * 1000),
            )
        )

        res = self.get_success(self.auth_handler.consume_login_token(token))
        self.assertEqual(self.user1, res.user_id)
        self.assertEqual(None, res.auth_provider_id)

    def test_login_token_reuse_fails(self) -> None:
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(
                self.user1,
                duration_ms=(5 * 1000),
            )
        )

        self.get_success(self.auth_handler.consume_login_token(token))

        self.get_failure(
            self.auth_handler.consume_login_token(token),
            AuthError,
        )

    def test_login_token_expires(self) -> None:
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(
                self.user1,
                duration_ms=(5 * 1000),
            )
        )

        # when we advance the clock, the token should be rejected
        self.reactor.advance(6)
        self.get_failure(
            self.auth_handler.consume_login_token(token),
            AuthError,
        )

    def test_login_token_gives_auth_provider(self) -> None:
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(
                self.user1,
                auth_provider_id="my_idp",
                auth_provider_session_id="11-22-33-44",
                duration_ms=(5 * 1000),
            )
        )
        res = self.get_success(self.auth_handler.consume_login_token(token))
        self.assertEqual(self.user1, res.user_id)
        self.assertEqual("my_idp", res.auth_provider_id)
        self.assertEqual("11-22-33-44", res.auth_provider_session_id)

    def test_mau_limits_disabled(self) -> None:
        self.auth_blocking._limit_usage_by_mau = False
        # Ensure does not throw exception
        self.get_success(
            self.auth_handler.create_access_token_for_user_id(
                self.user1, device_id=None, valid_until_ms=None
            )
        )

        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(self.user1)
        )

        self.assertIsNotNone(self.token_login(token))

    def test_mau_limits_exceeded_large(self) -> None:
        self.auth_blocking._limit_usage_by_mau = True
        self.hs.get_datastores().main.get_monthly_active_count = AsyncMock(
            return_value=self.large_number_of_users
        )

        self.get_failure(
            self.auth_handler.create_access_token_for_user_id(
                self.user1, device_id=None, valid_until_ms=None
            ),
            ResourceLimitError,
        )

        self.hs.get_datastores().main.get_monthly_active_count = AsyncMock(
            return_value=self.large_number_of_users
        )
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(self.user1)
        )
        self.assertIsNone(self.token_login(token))

    def test_mau_limits_parity(self) -> None:
        # Ensure we're not at the unix epoch.
        self.reactor.advance(1)
        self.auth_blocking._limit_usage_by_mau = True

        # Set the server to be at the edge of too many users.
        self.hs.get_datastores().main.get_monthly_active_count = AsyncMock(
            return_value=self.auth_blocking._max_mau_value
        )

        # If not in monthly active cohort
        self.get_failure(
            self.auth_handler.create_access_token_for_user_id(
                self.user1, device_id=None, valid_until_ms=None
            ),
            ResourceLimitError,
        )
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(self.user1)
        )
        self.assertIsNone(self.token_login(token))

        # If in monthly active cohort
        self.hs.get_datastores().main.user_last_seen_monthly_active = AsyncMock(
            return_value=self.clock.time_msec()
        )
        self.get_success(
            self.auth_handler.create_access_token_for_user_id(
                self.user1, device_id=None, valid_until_ms=None
            )
        )
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(self.user1)
        )
        self.assertIsNotNone(self.token_login(token))

    def test_mau_limits_not_exceeded(self) -> None:
        self.auth_blocking._limit_usage_by_mau = True

        self.hs.get_datastores().main.get_monthly_active_count = AsyncMock(
            return_value=self.small_number_of_users
        )
        # Ensure does not raise exception
        self.get_success(
            self.auth_handler.create_access_token_for_user_id(
                self.user1, device_id=None, valid_until_ms=None
            )
        )

        self.hs.get_datastores().main.get_monthly_active_count = AsyncMock(
            return_value=self.small_number_of_users
        )
        token = self.get_success(
            self.auth_handler.create_login_token_for_user_id(self.user1)
        )
        self.assertIsNotNone(self.token_login(token))
