# Copyright 2019 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.

from http import HTTPStatus

from twisted.test.proto_helpers import MemoryReactor

from synapse.api.constants import LoginType
from synapse.api.errors import Codes
from synapse.rest import admin
from synapse.rest.client import account, login, password_policy, register
from synapse.server import HomeServer
from synapse.util import Clock

from tests import unittest


class PasswordPolicyTestCase(unittest.HomeserverTestCase):
    """Tests the password policy feature and its compliance with MSC2000.

    When validating a password, Synapse does the necessary checks in this order:

        1. Password is long enough
        2. Password contains digit(s)
        3. Password contains symbol(s)
        4. Password contains uppercase letter(s)
        5. Password contains lowercase letter(s)

    For each test below that checks whether a password triggers the right error code,
    that test provides a password good enough to pass the previous tests, but not the
    one it is currently testing (nor any test that comes afterward).
    """

    servlets = [
        admin.register_servlets_for_client_rest_resource,
        login.register_servlets,
        register.register_servlets,
        password_policy.register_servlets,
        account.register_servlets,
    ]

    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
        self.register_url = "/_matrix/client/r0/register"
        self.policy = {
            "enabled": True,
            "minimum_length": 10,
            "require_digit": True,
            "require_symbol": True,
            "require_lowercase": True,
            "require_uppercase": True,
        }

        config = self.default_config()
        config["password_config"] = {
            "policy": self.policy,
        }

        hs = self.setup_test_homeserver(config=config)
        return hs

    def test_get_policy(self) -> None:
        """Tests if the /password_policy endpoint returns the configured policy."""

        channel = self.make_request("GET", "/_matrix/client/r0/password_policy")

        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
        self.assertEqual(
            channel.json_body,
            {
                "m.minimum_length": 10,
                "m.require_digit": True,
                "m.require_symbol": True,
                "m.require_lowercase": True,
                "m.require_uppercase": True,
            },
            channel.result,
        )

    def test_password_too_short(self) -> None:
        request_data = {"username": "kermit", "password": "shorty"}
        channel = self.make_request("POST", self.register_url, request_data)

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.PASSWORD_TOO_SHORT,
            channel.result,
        )

    def test_password_no_digit(self) -> None:
        request_data = {"username": "kermit", "password": "longerpassword"}
        channel = self.make_request("POST", self.register_url, request_data)

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.PASSWORD_NO_DIGIT,
            channel.result,
        )

    def test_password_no_symbol(self) -> None:
        request_data = {"username": "kermit", "password": "l0ngerpassword"}
        channel = self.make_request("POST", self.register_url, request_data)

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.PASSWORD_NO_SYMBOL,
            channel.result,
        )

    def test_password_no_uppercase(self) -> None:
        request_data = {"username": "kermit", "password": "l0ngerpassword!"}
        channel = self.make_request("POST", self.register_url, request_data)

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.PASSWORD_NO_UPPERCASE,
            channel.result,
        )

    def test_password_no_lowercase(self) -> None:
        request_data = {"username": "kermit", "password": "L0NGERPASSWORD!"}
        channel = self.make_request("POST", self.register_url, request_data)

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(
            channel.json_body["errcode"],
            Codes.PASSWORD_NO_LOWERCASE,
            channel.result,
        )

    def test_password_compliant(self) -> None:
        request_data = {"username": "kermit", "password": "L0ngerpassword!"}
        channel = self.make_request("POST", self.register_url, request_data)

        # Getting a 401 here means the password has passed validation and the server has
        # responded with a list of registration flows.
        self.assertEqual(channel.code, HTTPStatus.UNAUTHORIZED, channel.result)

    def test_password_change(self) -> None:
        """This doesn't test every possible use case, only that hitting /account/password
        triggers the password validation code.
        """
        compliant_password = "C0mpl!antpassword"
        not_compliant_password = "notcompliantpassword"

        user_id = self.register_user("kermit", compliant_password)
        tok = self.login("kermit", compliant_password)

        request_data = {
            "new_password": not_compliant_password,
            "auth": {
                "password": compliant_password,
                "type": LoginType.PASSWORD,
                "user": user_id,
            },
        }
        channel = self.make_request(
            "POST",
            "/_matrix/client/r0/account/password",
            request_data,
            access_token=tok,
        )

        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
        self.assertEqual(channel.json_body["errcode"], Codes.PASSWORD_NO_DIGIT)