#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# 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 http import HTTPStatus
from typing import Any, Generator, Tuple, cast
from unittest.mock import AsyncMock, Mock, call

from twisted.internet import defer, reactor as _reactor

from synapse.logging.context import SENTINEL_CONTEXT, LoggingContext, current_context
from synapse.rest.client.transactions import CLEANUP_PERIOD_MS, HttpTransactionCache
from synapse.types import ISynapseReactor, JsonDict
from synapse.util import Clock

from tests import unittest
from tests.utils import MockClock

reactor = cast(ISynapseReactor, _reactor)


class HttpTransactionCacheTestCase(unittest.TestCase):
    def setUp(self) -> None:
        self.clock = MockClock()
        self.hs = Mock()
        self.hs.get_clock = Mock(return_value=self.clock)
        self.hs.get_auth = Mock()
        self.cache = HttpTransactionCache(self.hs)

        self.mock_http_response = (HTTPStatus.OK, {"result": "GOOD JOB!"})

        # Here we make sure that we're setting all the fields that HttpTransactionCache
        # uses to build the transaction key.
        self.mock_request = Mock()
        self.mock_request.path = b"/foo/bar"
        self.mock_requester = Mock()
        self.mock_requester.app_service = None
        self.mock_requester.is_guest = False
        self.mock_requester.access_token_id = 1234

    @defer.inlineCallbacks
    def test_executes_given_function(
        self,
    ) -> Generator["defer.Deferred[Any]", object, None]:
        cb = AsyncMock(return_value=self.mock_http_response)
        res = yield self.cache.fetch_or_execute_request(
            self.mock_request, self.mock_requester, cb, "some_arg", keyword="arg"
        )
        cb.assert_called_once_with("some_arg", keyword="arg")
        self.assertEqual(res, self.mock_http_response)

    @defer.inlineCallbacks
    def test_deduplicates_based_on_key(
        self,
    ) -> Generator["defer.Deferred[Any]", object, None]:
        cb = AsyncMock(return_value=self.mock_http_response)
        for i in range(3):  # invoke multiple times
            res = yield self.cache.fetch_or_execute_request(
                self.mock_request,
                self.mock_requester,
                cb,
                "some_arg",
                keyword="arg",
                changing_args=i,
            )
            self.assertEqual(res, self.mock_http_response)
        # expect only a single call to do the work
        cb.assert_called_once_with("some_arg", keyword="arg", changing_args=0)

    @defer.inlineCallbacks
    def test_logcontexts_with_async_result(
        self,
    ) -> Generator["defer.Deferred[Any]", object, None]:
        @defer.inlineCallbacks
        def cb() -> Generator["defer.Deferred[object]", object, Tuple[int, JsonDict]]:
            yield Clock(reactor).sleep(0)
            return 1, {}

        @defer.inlineCallbacks
        def test() -> Generator["defer.Deferred[Any]", object, None]:
            with LoggingContext("c") as c1:
                res = yield self.cache.fetch_or_execute_request(
                    self.mock_request, self.mock_requester, cb
                )
                self.assertIs(current_context(), c1)
                self.assertEqual(res, (1, {}))

        # run the test twice in parallel
        d = defer.gatherResults([test(), test()])
        self.assertIs(current_context(), SENTINEL_CONTEXT)
        yield d
        self.assertIs(current_context(), SENTINEL_CONTEXT)

    @defer.inlineCallbacks
    def test_does_not_cache_exceptions(
        self,
    ) -> Generator["defer.Deferred[Any]", object, None]:
        """Checks that, if the callback throws an exception, it is called again
        for the next request.
        """
        called = [False]

        def cb() -> "defer.Deferred[Tuple[int, JsonDict]]":
            if called[0]:
                # return a valid result the second time
                return defer.succeed(self.mock_http_response)

            called[0] = True
            raise Exception("boo")

        with LoggingContext("test") as test_context:
            try:
                yield self.cache.fetch_or_execute_request(
                    self.mock_request, self.mock_requester, cb
                )
            except Exception as e:
                self.assertEqual(e.args[0], "boo")
            self.assertIs(current_context(), test_context)

            res = yield self.cache.fetch_or_execute_request(
                self.mock_request, self.mock_requester, cb
            )
            self.assertEqual(res, self.mock_http_response)
            self.assertIs(current_context(), test_context)

    @defer.inlineCallbacks
    def test_does_not_cache_failures(
        self,
    ) -> Generator["defer.Deferred[Any]", object, None]:
        """Checks that, if the callback returns a failure, it is called again
        for the next request.
        """
        called = [False]

        def cb() -> "defer.Deferred[Tuple[int, JsonDict]]":
            if called[0]:
                # return a valid result the second time
                return defer.succeed(self.mock_http_response)

            called[0] = True
            return defer.fail(Exception("boo"))

        with LoggingContext("test") as test_context:
            try:
                yield self.cache.fetch_or_execute_request(
                    self.mock_request, self.mock_requester, cb
                )
            except Exception as e:
                self.assertEqual(e.args[0], "boo")
            self.assertIs(current_context(), test_context)

            res = yield self.cache.fetch_or_execute_request(
                self.mock_request, self.mock_requester, cb
            )
            self.assertEqual(res, self.mock_http_response)
            self.assertIs(current_context(), test_context)

    @defer.inlineCallbacks
    def test_cleans_up(self) -> Generator["defer.Deferred[Any]", object, None]:
        cb = AsyncMock(return_value=self.mock_http_response)
        yield self.cache.fetch_or_execute_request(
            self.mock_request, self.mock_requester, cb, "an arg"
        )
        # should NOT have cleaned up yet
        self.clock.advance_time_msec(CLEANUP_PERIOD_MS / 2)

        yield self.cache.fetch_or_execute_request(
            self.mock_request, self.mock_requester, cb, "an arg"
        )
        # still using cache
        cb.assert_called_once_with("an arg")

        self.clock.advance_time_msec(CLEANUP_PERIOD_MS)

        yield self.cache.fetch_or_execute_request(
            self.mock_request, self.mock_requester, cb, "an arg"
        )
        # no longer using cache
        self.assertEqual(cb.call_count, 2)
        self.assertEqual(cb.call_args_list, [call("an arg"), call("an arg")])
