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

"""
Tests for L{twisted.internet.base}.
"""

import socket
try:
    from Queue import Queue
except ImportError:
    from queue import Queue

from zope.interface import implementer

from twisted.python.threadpool import ThreadPool
from twisted.python._utilpy3 import setIDFunction
from twisted.internet.interfaces import IReactorTime, IReactorThreads
from twisted.internet.error import DNSLookupError
from twisted.internet.base import ThreadedResolver, DelayedCall
from twisted.internet.task import Clock
from twisted.trial.unittest import TestCase


@implementer(IReactorTime, IReactorThreads)
class FakeReactor(object):
    """
    A fake reactor implementation which just supports enough reactor APIs for
    L{ThreadedResolver}.
    """

    def __init__(self):
        self._clock = Clock()
        self.callLater = self._clock.callLater

        self._threadpool = ThreadPool()
        self._threadpool.start()
        self.getThreadPool = lambda: self._threadpool

        self._threadCalls = Queue()


    def callFromThread(self, f, *args, **kwargs):
        self._threadCalls.put((f, args, kwargs))


    def _runThreadCalls(self):
        f, args, kwargs = self._threadCalls.get()
        f(*args, **kwargs)


    def _stop(self):
        self._threadpool.stop()



class ThreadedResolverTests(TestCase):
    """
    Tests for L{ThreadedResolver}.
    """
    def test_success(self):
        """
        L{ThreadedResolver.getHostByName} returns a L{Deferred} which fires
        with the value returned by the call to L{socket.gethostbyname} in the
        threadpool of the reactor passed to L{ThreadedResolver.__init__}.
        """
        ip = "10.0.0.17"
        name = "foo.bar.example.com"
        timeout = 30

        reactor = FakeReactor()
        self.addCleanup(reactor._stop)

        lookedUp = []
        resolvedTo = []
        def fakeGetHostByName(name):
            lookedUp.append(name)
            return ip

        self.patch(socket, 'gethostbyname', fakeGetHostByName)

        resolver = ThreadedResolver(reactor)
        d = resolver.getHostByName(name, (timeout,))
        d.addCallback(resolvedTo.append)

        reactor._runThreadCalls()

        self.assertEqual(lookedUp, [name])
        self.assertEqual(resolvedTo, [ip])

        # Make sure that any timeout-related stuff gets cleaned up.
        reactor._clock.advance(timeout + 1)
        self.assertEqual(reactor._clock.calls, [])


    def test_failure(self):
        """
        L{ThreadedResolver.getHostByName} returns a L{Deferred} which fires a
        L{Failure} if the call to L{socket.gethostbyname} raises an exception.
        """
        timeout = 30

        reactor = FakeReactor()
        self.addCleanup(reactor._stop)

        def fakeGetHostByName(name):
            raise IOError("ENOBUFS (this is a funny joke)")

        self.patch(socket, 'gethostbyname', fakeGetHostByName)

        failedWith = []
        resolver = ThreadedResolver(reactor)
        d = resolver.getHostByName("some.name", (timeout,))
        self.assertFailure(d, DNSLookupError)
        d.addCallback(failedWith.append)

        reactor._runThreadCalls()

        self.assertEqual(len(failedWith), 1)

        # Make sure that any timeout-related stuff gets cleaned up.
        reactor._clock.advance(timeout + 1)
        self.assertEqual(reactor._clock.calls, [])


    def test_timeout(self):
        """
        If L{socket.gethostbyname} does not complete before the specified
        timeout elapsed, the L{Deferred} returned by
        L{ThreadedResolver.getHostByBame} fails with L{DNSLookupError}.
        """
        timeout = 10

        reactor = FakeReactor()
        self.addCleanup(reactor._stop)

        result = Queue()
        def fakeGetHostByName(name):
            raise result.get()

        self.patch(socket, 'gethostbyname', fakeGetHostByName)

        failedWith = []
        resolver = ThreadedResolver(reactor)
        d = resolver.getHostByName("some.name", (timeout,))
        self.assertFailure(d, DNSLookupError)
        d.addCallback(failedWith.append)

        reactor._clock.advance(timeout - 1)
        self.assertEqual(failedWith, [])
        reactor._clock.advance(1)
        self.assertEqual(len(failedWith), 1)

        # Eventually the socket.gethostbyname does finish - in this case, with
        # an exception.  Nobody cares, though.
        result.put(IOError("The I/O was errorful"))



def nothing():
    """
    Function used by L{DelayedCallTests.test_str}.
    """


class DelayedCallTests(TestCase):
    """
    Tests for L{DelayedCall}.
    """
    def _getDelayedCallAt(self, time):
        """
        Get a L{DelayedCall} instance at a given C{time}.

        @param time: The absolute time at which the returned L{DelayedCall}
            will be scheduled.
        """
        def noop(call):
            pass
        return DelayedCall(time, lambda: None, (), {}, noop, noop, None)


    def setUp(self):
        """
        Create two L{DelayedCall} instanced scheduled to run at different
        times.
        """
        self.zero = self._getDelayedCallAt(0)
        self.one = self._getDelayedCallAt(1)


    def test_str(self):
        """
        The string representation of a L{DelayedCall} instance, as returned by
        C{str}, includes the unsigned id of the instance, as well as its state,
        the function to be called, and the function arguments.
        """
        dc = DelayedCall(12, nothing, (3, ), {"A": 5}, None, None, lambda: 1.5)
        ids = {dc: 200}
        def fakeID(obj):
            try:
                return ids[obj]
            except (TypeError, KeyError):
                return id(obj)
        self.addCleanup(setIDFunction, setIDFunction(fakeID))
        self.assertEqual(
            str(dc),
            "<DelayedCall 0xc8 [10.5s] called=0 cancelled=0 nothing(3, A=5)>")


    def test_lt(self):
        """
        For two instances of L{DelayedCall} C{a} and C{b}, C{a < b} is true
        if and only if C{a} is scheduled to run before C{b}.
        """
        zero, one = self.zero, self.one
        self.assertTrue(zero < one)
        self.assertFalse(one < zero)
        self.assertFalse(zero < zero)
        self.assertFalse(one < one)


    def test_le(self):
        """
        For two instances of L{DelayedCall} C{a} and C{b}, C{a <= b} is true
        if and only if C{a} is scheduled to run before C{b} or at the same
        time as C{b}.
        """
        zero, one = self.zero, self.one
        self.assertTrue(zero <= one)
        self.assertFalse(one <= zero)
        self.assertTrue(zero <= zero)
        self.assertTrue(one <= one)


    def test_gt(self):
        """
        For two instances of L{DelayedCall} C{a} and C{b}, C{a > b} is true
        if and only if C{a} is scheduled to run after C{b}.
        """
        zero, one = self.zero, self.one
        self.assertTrue(one > zero)
        self.assertFalse(zero > one)
        self.assertFalse(zero > zero)
        self.assertFalse(one > one)


    def test_ge(self):
        """
        For two instances of L{DelayedCall} C{a} and C{b}, C{a > b} is true
        if and only if C{a} is scheduled to run after C{b} or at the same
        time as C{b}.
        """
        zero, one = self.zero, self.one
        self.assertTrue(one >= zero)
        self.assertFalse(zero >= one)
        self.assertTrue(zero >= zero)
        self.assertTrue(one >= one)


    def test_eq(self):
        """
        A L{DelayedCall} instance is only equal to itself.
        """
        # Explicitly use == here, instead of assertEqual, to be more
        # confident __eq__ is being tested.
        self.assertFalse(self.zero == self.one)
        self.assertTrue(self.zero == self.zero)
        self.assertTrue(self.one == self.one)


    def test_ne(self):
        """
        A L{DelayedCall} instance is not equal to any other object.
        """
        # Explicitly use != here, instead of assertEqual, to be more
        # confident __ne__ is being tested.
        self.assertTrue(self.zero != self.one)
        self.assertFalse(self.zero != self.zero)
        self.assertFalse(self.one != self.one)
