# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for (new code in) L{twisted.application.internet}.
"""

from __future__ import absolute_import, division

import pickle

from zope.interface import implementer
from zope.interface.verify import verifyClass

from twisted.internet.protocol import Factory
from twisted.trial.unittest import TestCase
from twisted.application import internet
from twisted.application.internet import (
        StreamServerEndpointService, TimerService)
from twisted.internet.interfaces import IStreamServerEndpoint, IListeningPort
from twisted.internet.defer import Deferred, CancelledError
from twisted.internet import task
from twisted.python.failure import Failure


def fakeTargetFunction():
    """
    A fake target function for testing TimerService which does nothing.
    """
    pass



@implementer(IStreamServerEndpoint)
class FakeServer(object):
    """
    In-memory implementation of L{IStreamServerEndpoint}.

    @ivar result: The L{Deferred} resulting from the call to C{listen}, after
        C{listen} has been called.

    @ivar factory: The factory passed to C{listen}.

    @ivar cancelException: The exception to errback C{self.result} when it is
        cancelled.

    @ivar port: The L{IListeningPort} which C{listen}'s L{Deferred} will fire
        with.

    @ivar listenAttempts: The number of times C{listen} has been invoked.

    @ivar failImmediately: If set, the exception to fail the L{Deferred}
        returned from C{listen} before it is returned.
    """
    result = None
    factory = None
    failImmediately = None
    cancelException = CancelledError()
    listenAttempts = 0

    def __init__(self):
        self.port = FakePort()


    def listen(self, factory):
        """
        Return a Deferred and store it for future use.  (Implementation of
        L{IStreamServerEndpoint}).
        """
        self.listenAttempts += 1
        self.factory = factory
        self.result = Deferred(
            canceller=lambda d: d.errback(self.cancelException))
        if self.failImmediately is not None:
            self.result.errback(self.failImmediately)
        return self.result


    def startedListening(self):
        """
        Test code should invoke this method after causing C{listen} to be
        invoked in order to fire the L{Deferred} previously returned from
        C{listen}.
        """
        self.result.callback(self.port)


    def stoppedListening(self):
        """
        Test code should invoke this method after causing C{stopListening} to
        be invoked on the port fired from the L{Deferred} returned from
        C{listen} in order to cause the L{Deferred} returned from
        C{stopListening} to fire.
        """
        self.port.deferred.callback(None)

verifyClass(IStreamServerEndpoint, FakeServer)



@implementer(IListeningPort)
class FakePort(object):
    """
    Fake L{IListeningPort} implementation.

    @ivar deferred: The L{Deferred} returned by C{stopListening}.
    """
    deferred = None

    def stopListening(self):
        self.deferred = Deferred()
        return self.deferred

verifyClass(IStreamServerEndpoint, FakeServer)



class EndpointServiceTests(TestCase):
    """
    Tests for L{twisted.application.internet}.
    """

    def setUp(self):
        """
        Construct a stub server, a stub factory, and a
        L{StreamServerEndpointService} to test.
        """
        self.fakeServer = FakeServer()
        self.factory = Factory()
        self.svc = StreamServerEndpointService(self.fakeServer, self.factory)


    def test_privilegedStartService(self):
        """
        L{StreamServerEndpointService.privilegedStartService} calls its
        endpoint's C{listen} method with its factory.
        """
        self.svc.privilegedStartService()
        self.assertIdentical(self.factory, self.fakeServer.factory)


    def test_synchronousRaiseRaisesSynchronously(self, thunk=None):
        """
        L{StreamServerEndpointService.startService} should raise synchronously
        if the L{Deferred} returned by its wrapped
        L{IStreamServerEndpoint.listen} has already fired with an errback and
        the L{StreamServerEndpointService}'s C{_raiseSynchronously} flag has
        been set.  This feature is necessary to preserve compatibility with old
        behavior of L{twisted.internet.strports.service}, which is to return a
        service which synchronously raises an exception from C{startService}
        (so that, among other things, twistd will not start running).  However,
        since L{IStreamServerEndpoint.listen} may fail asynchronously, it is
        a bad idea to rely on this behavior.
        """
        self.fakeServer.failImmediately = ZeroDivisionError()
        self.svc._raiseSynchronously = True
        self.assertRaises(ZeroDivisionError, thunk or self.svc.startService)


    def test_synchronousRaisePrivileged(self):
        """
        L{StreamServerEndpointService.privilegedStartService} should behave the
        same as C{startService} with respect to
        L{EndpointServiceTests.test_synchronousRaiseRaisesSynchronously}.
        """
        self.test_synchronousRaiseRaisesSynchronously(
            self.svc.privilegedStartService)


    def test_failReportsError(self):
        """
        L{StreamServerEndpointService.startService} and
        L{StreamServerEndpointService.privilegedStartService} should both log
        an exception when the L{Deferred} returned from their wrapped
        L{IStreamServerEndpoint.listen} fails.
        """
        self.svc.startService()
        self.fakeServer.result.errback(ZeroDivisionError())
        logged = self.flushLoggedErrors(ZeroDivisionError)
        self.assertEqual(len(logged), 1)


    def test_synchronousFailReportsError(self):
        """
        Without the C{_raiseSynchronously} compatibility flag, failing
        immediately has the same behavior as failing later; it logs the error.
        """
        self.fakeServer.failImmediately = ZeroDivisionError()
        self.svc.startService()
        logged = self.flushLoggedErrors(ZeroDivisionError)
        self.assertEqual(len(logged), 1)


    def test_startServiceUnstarted(self):
        """
        L{StreamServerEndpointService.startService} sets the C{running} flag,
        and calls its endpoint's C{listen} method with its factory, if it
        has not yet been started.
        """
        self.svc.startService()
        self.assertIdentical(self.factory, self.fakeServer.factory)
        self.assertEqual(self.svc.running, True)


    def test_startServiceStarted(self):
        """
        L{StreamServerEndpointService.startService} sets the C{running} flag,
        but nothing else, if the service has already been started.
        """
        self.test_privilegedStartService()
        self.svc.startService()
        self.assertEqual(self.fakeServer.listenAttempts, 1)
        self.assertEqual(self.svc.running, True)


    def test_stopService(self):
        """
        L{StreamServerEndpointService.stopService} calls C{stopListening} on
        the L{IListeningPort} returned from its endpoint, returns the
        C{Deferred} from stopService, and sets C{running} to C{False}.
        """
        self.svc.privilegedStartService()
        self.fakeServer.startedListening()
        # Ensure running gets set to true
        self.svc.startService()
        result = self.svc.stopService()
        l = []
        result.addCallback(l.append)
        self.assertEqual(len(l), 0)
        self.fakeServer.stoppedListening()
        self.assertEqual(len(l), 1)
        self.assertFalse(self.svc.running)


    def test_stopServiceBeforeStartFinished(self):
        """
        L{StreamServerEndpointService.stopService} cancels the L{Deferred}
        returned by C{listen} if it has not yet fired.  No error will be logged
        about the cancellation of the listen attempt.
        """
        self.svc.privilegedStartService()
        result = self.svc.stopService()
        l = []
        result.addBoth(l.append)
        self.assertEqual(l, [None])
        self.assertEqual(self.flushLoggedErrors(CancelledError), [])


    def test_stopServiceCancelStartError(self):
        """
        L{StreamServerEndpointService.stopService} cancels the L{Deferred}
        returned by C{listen} if it has not fired yet.  An error will be logged
        if the resulting exception is not L{CancelledError}.
        """
        self.fakeServer.cancelException = ZeroDivisionError()
        self.svc.privilegedStartService()
        result = self.svc.stopService()
        l = []
        result.addCallback(l.append)
        self.assertEqual(l, [None])
        stoppingErrors = self.flushLoggedErrors(ZeroDivisionError)
        self.assertEqual(len(stoppingErrors), 1)



class TimerServiceTests(TestCase):
    """
    Tests for L{twisted.application.internet.TimerService}.

    @type timer: L{TimerService}
    @ivar timer: service to test

    @type clock: L{task.Clock}
    @ivar clock: source of time

    @type deferred: L{Deferred}
    @ivar deferred: deferred returned by L{TimerServiceTests.call}.
    """

    def setUp(self):
        self.timer = TimerService(2, self.call)
        self.clock = self.timer.clock = task.Clock()
        self.deferred = Deferred()


    def call(self):
        """
        Function called by L{TimerService} being tested.

        @returns: C{self.deferred}
        @rtype: L{Deferred}
        """
        return self.deferred


    def test_startService(self):
        """
        When L{TimerService.startService} is called, it marks itself
        as running, creates a L{task.LoopingCall} and starts it.
        """
        self.timer.startService()
        self.assertTrue(self.timer.running, "Service is started")
        self.assertIsInstance(self.timer._loop, task.LoopingCall)
        self.assertIdentical(self.clock, self.timer._loop.clock)
        self.assertTrue(self.timer._loop.running, "LoopingCall is started")


    def test_startServiceRunsCallImmediately(self):
        """
        When L{TimerService.startService} is called, it calls the function
        immediately.
        """
        result = []
        self.timer.call = (result.append, (None,), {})
        self.timer.startService()
        self.assertEqual([None], result)


    def test_startServiceUsesGlobalReactor(self):
        """
        L{TimerService.startService} uses L{internet._maybeGlobalReactor} to
        choose the reactor to pass to L{task.LoopingCall}
        uses the global reactor.
        """
        otherClock = task.Clock()
        def getOtherClock(maybeReactor):
            return otherClock
        self.patch(internet, "_maybeGlobalReactor", getOtherClock)
        self.timer.startService()
        self.assertIdentical(otherClock, self.timer._loop.clock)


    def test_stopServiceWaits(self):
        """
        When L{TimerService.stopService} is called while a call is in progress.
        the L{Deferred} returned doesn't fire until after the call finishes.
        """
        self.timer.startService()
        d = self.timer.stopService()
        self.assertNoResult(d)
        self.assertEqual(True, self.timer.running)
        self.deferred.callback(object())
        self.assertIdentical(self.successResultOf(d), None)


    def test_stopServiceImmediately(self):
        """
        When L{TimerService.stopService} is called while a call isn't in progress.
        the L{Deferred} returned has already been fired.
        """
        self.timer.startService()
        self.deferred.callback(object())
        d = self.timer.stopService()
        self.assertIdentical(self.successResultOf(d), None)


    def test_failedCallLogsError(self):
        """
        When function passed to L{TimerService} returns a deferred that errbacks,
        the exception is logged, and L{TimerService.stopService} doesn't raise an error.
        """
        self.timer.startService()
        self.deferred.errback(Failure(ZeroDivisionError()))
        errors = self.flushLoggedErrors(ZeroDivisionError)
        self.assertEqual(1, len(errors))
        d = self.timer.stopService()
        self.assertIdentical(self.successResultOf(d), None)


    def test_pickleTimerServiceNotPickleLoop(self):
        """
        When pickling L{internet.TimerService}, it won't pickle
        L{internet.TimerService._loop}.
        """
        # We need a pickleable callable to test pickling TimerService. So we
        # can't use self.timer
        timer = TimerService(1, fakeTargetFunction)
        timer.startService()
        dumpedTimer = pickle.dumps(timer)
        timer.stopService()
        loadedTimer = pickle.loads(dumpedTimer)
        nothing = object()
        value = getattr(loadedTimer, "_loop", nothing)
        self.assertIdentical(nothing, value)


    def test_pickleTimerServiceNotPickleLoopFinished(self):
        """
        When pickling L{internet.TimerService}, it won't pickle
        L{internet.TimerService._loopFinished}.
        """
        # We need a pickleable callable to test pickling TimerService. So we
        # can't use self.timer
        timer = TimerService(1, fakeTargetFunction)
        timer.startService()
        dumpedTimer = pickle.dumps(timer)
        timer.stopService()
        loadedTimer = pickle.loads(dumpedTimer)
        nothing = object()
        value = getattr(loadedTimer, "_loopFinished", nothing)
        self.assertIdentical(nothing, value)