from synapse.rest.client.transactions import HttpTransactionCache
from synapse.rest.client.transactions import CLEANUP_PERIOD_MS
from twisted.internet import defer, reactor
from mock import Mock, call

from synapse.util import Clock
from synapse.util.logcontext import LoggingContext
from tests import unittest
from tests.utils import MockClock


class HttpTransactionCacheTestCase(unittest.TestCase):

    def setUp(self):
        self.clock = MockClock()
        self.cache = HttpTransactionCache(self.clock)

        self.mock_http_response = (200, "GOOD JOB!")
        self.mock_key = "foo"

    @defer.inlineCallbacks
    def test_executes_given_function(self):
        cb = Mock(
            return_value=defer.succeed(self.mock_http_response)
        )
        res = yield self.cache.fetch_or_execute(
            self.mock_key, 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):
        cb = Mock(
            return_value=defer.succeed(self.mock_http_response)
        )
        for i in range(3):  # invoke multiple times
            res = yield self.cache.fetch_or_execute(
                self.mock_key, 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):
        @defer.inlineCallbacks
        def cb():
            yield Clock(reactor).sleep(0)
            defer.returnValue("yay")

        @defer.inlineCallbacks
        def test():
            with LoggingContext("c") as c1:
                res = yield self.cache.fetch_or_execute(self.mock_key, cb)
                self.assertIs(LoggingContext.current_context(), c1)
                self.assertEqual(res, "yay")

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

    @defer.inlineCallbacks
    def test_does_not_cache_exceptions(self):
        """Checks that, if the callback throws an exception, it is called again
        for the next request.
        """
        called = [False]

        def cb():
            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(self.mock_key, cb)
            except Exception as e:
                self.assertEqual(e.message, "boo")
            self.assertIs(LoggingContext.current_context(), test_context)

            res = yield self.cache.fetch_or_execute(self.mock_key, cb)
            self.assertEqual(res, self.mock_http_response)
            self.assertIs(LoggingContext.current_context(), test_context)

    @defer.inlineCallbacks
    def test_does_not_cache_failures(self):
        """Checks that, if the callback returns a failure, it is called again
        for the next request.
        """
        called = [False]

        def cb():
            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(self.mock_key, cb)
            except Exception as e:
                self.assertEqual(e.message, "boo")
            self.assertIs(LoggingContext.current_context(), test_context)

            res = yield self.cache.fetch_or_execute(self.mock_key, cb)
            self.assertEqual(res, self.mock_http_response)
            self.assertIs(LoggingContext.current_context(), test_context)

    @defer.inlineCallbacks
    def test_cleans_up(self):
        cb = Mock(
            return_value=defer.succeed(self.mock_http_response)
        )
        yield self.cache.fetch_or_execute(
            self.mock_key, cb, "an arg"
        )
        # should NOT have cleaned up yet
        self.clock.advance_time_msec(CLEANUP_PERIOD_MS / 2)

        yield self.cache.fetch_or_execute(
            self.mock_key, 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(
            self.mock_key, 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",)]
        )