# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
#
# 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 pymacaroons
from twisted.internet import defer

import synapse
import synapse.api.errors
from synapse.handlers.auth import AuthHandler
from tests import unittest
from tests.utils import setup_test_homeserver


class AuthHandlers(object):
    def __init__(self, hs):
        self.auth_handler = AuthHandler(hs)


class AuthTestCase(unittest.TestCase):
    @defer.inlineCallbacks
    def setUp(self):
        self.hs = yield setup_test_homeserver(handlers=None)
        self.hs.handlers = AuthHandlers(self.hs)
        self.auth_handler = self.hs.handlers.auth_handler
        self.macaroon_generator = self.hs.get_macaroon_generator()

    def test_token_is_a_macaroon(self):
        token = self.macaroon_generator.generate_access_token("some_user")
        # Check that we can parse the thing with pymacaroons
        macaroon = pymacaroons.Macaroon.deserialize(token)
        # The most basic of sanity checks
        if "some_user" not in macaroon.inspect():
            self.fail("some_user was not in %s" % macaroon.inspect())

    def test_macaroon_caveats(self):
        self.hs.clock.now = 5000

        token = self.macaroon_generator.generate_access_token("a_user")
        macaroon = pymacaroons.Macaroon.deserialize(token)

        def verify_gen(caveat):
            return caveat == "gen = 1"

        def verify_user(caveat):
            return caveat == "user_id = a_user"

        def verify_type(caveat):
            return caveat == "type = access"

        def verify_nonce(caveat):
            return caveat.startswith("nonce =")

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

    def test_short_term_login_token_gives_user_id(self):
        self.hs.clock.now = 1000

        token = self.macaroon_generator.generate_short_term_login_token(
            "a_user", 5000
        )

        self.assertEqual(
            "a_user",
            self.auth_handler.validate_short_term_login_token_and_get_user_id(
                token
            )
        )

        # when we advance the clock, the token should be rejected
        self.hs.clock.now = 6000
        with self.assertRaises(synapse.api.errors.AuthError):
            self.auth_handler.validate_short_term_login_token_and_get_user_id(
                token
            )

    def test_short_term_login_token_cannot_replace_user_id(self):
        token = self.macaroon_generator.generate_short_term_login_token(
            "a_user", 5000
        )
        macaroon = pymacaroons.Macaroon.deserialize(token)

        self.assertEqual(
            "a_user",
            self.auth_handler.validate_short_term_login_token_and_get_user_id(
                macaroon.serialize()
            )
        )

        # add another "user_id" caveat, which might allow us to override the
        # user_id.
        macaroon.add_first_party_caveat("user_id = b_user")

        with self.assertRaises(synapse.api.errors.AuthError):
            self.auth_handler.validate_short_term_login_token_and_get_user_id(
                macaroon.serialize()
            )