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

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

import errno
from array import array
from struct import pack
from socket import AF_INET6, AF_INET, SOCK_STREAM, SOL_SOCKET, error, socket

from zope.interface.verify import verifyClass

from twisted.trial import unittest
from twisted.python.log import msg
from twisted.internet.interfaces import IPushProducer

try:
    from twisted.internet.iocpreactor import iocpsupport as _iocp, tcp, udp
    from twisted.internet.iocpreactor.reactor import IOCPReactor, EVENTS_PER_LOOP, KEY_NORMAL
    from twisted.internet.iocpreactor.interfaces import IReadWriteHandle
    from twisted.internet.iocpreactor.const import SO_UPDATE_ACCEPT_CONTEXT
    from twisted.internet.iocpreactor.abstract import FileHandle
except ImportError:
    skip = 'This test only applies to IOCPReactor'

try:
    socket(AF_INET6, SOCK_STREAM).close()
except error as e:
    ipv6Skip = str(e)
else:
    ipv6Skip = None

class SupportTests(unittest.TestCase):
    """
    Tests for L{twisted.internet.iocpreactor.iocpsupport}, low-level reactor
    implementation helpers.
    """
    def _acceptAddressTest(self, family, localhost):
        """
        Create a C{SOCK_STREAM} connection to localhost using a socket with an
        address family of C{family} and assert that the result of
        L{iocpsupport.get_accept_addrs} is consistent with the result of
        C{socket.getsockname} and C{socket.getpeername}.
        """
        msg("family = %r" % (family,))
        port = socket(family, SOCK_STREAM)
        self.addCleanup(port.close)
        port.bind(('', 0))
        port.listen(1)
        client = socket(family, SOCK_STREAM)
        self.addCleanup(client.close)
        client.setblocking(False)
        try:
            client.connect((localhost, port.getsockname()[1]))
        except error as e:
            self.assertIn(e.errno, (errno.EINPROGRESS, errno.EWOULDBLOCK))

        server = socket(family, SOCK_STREAM)
        self.addCleanup(server.close)
        buff = array('B', b'\0' * 256)
        self.assertEqual(
            0, _iocp.accept(port.fileno(), server.fileno(), buff, None))
        server.setsockopt(
            SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT, pack('P', port.fileno()))
        self.assertEqual(
            (family, client.getpeername()[:2], client.getsockname()[:2]),
            _iocp.get_accept_addrs(server.fileno(), buff))


    def test_ipv4AcceptAddress(self):
        """
        L{iocpsupport.get_accept_addrs} returns a three-tuple of address
        information about the socket associated with the file descriptor passed
        to it.  For a connection using IPv4:

          - the first element is C{AF_INET}
          - the second element is a two-tuple of a dotted decimal notation IPv4
            address and a port number giving the peer address of the connection
          - the third element is the same type giving the host address of the
            connection
        """
        self._acceptAddressTest(AF_INET, '127.0.0.1')


    def test_ipv6AcceptAddress(self):
        """
        Like L{test_ipv4AcceptAddress}, but for IPv6 connections.  In this case:

          - the first element is C{AF_INET6}
          - the second element is a two-tuple of a hexadecimal IPv6 address
            literal and a port number giving the peer address of the connection
          - the third element is the same type giving the host address of the
            connection
        """
        self._acceptAddressTest(AF_INET6, '::1')
    if ipv6Skip is not None:
        test_ipv6AcceptAddress.skip = ipv6Skip



class IOCPReactorTests(unittest.TestCase):
    def test_noPendingTimerEvents(self):
        """
        Test reactor behavior (doIteration) when there are no pending time
        events.
        """
        ir = IOCPReactor()
        ir.wakeUp()
        self.assertFalse(ir.doIteration(None))


    def test_reactorInterfaces(self):
        """
        Verify that IOCP socket-representing classes implement IReadWriteHandle
        """
        self.assertTrue(verifyClass(IReadWriteHandle, tcp.Connection))
        self.assertTrue(verifyClass(IReadWriteHandle, udp.Port))


    def test_fileHandleInterfaces(self):
        """
        Verify that L{Filehandle} implements L{IPushProducer}.
        """
        self.assertTrue(verifyClass(IPushProducer, FileHandle))


    def test_maxEventsPerIteration(self):
        """
        Verify that we don't lose an event when more than EVENTS_PER_LOOP
        events occur in the same reactor iteration
        """
        class FakeFD:
            counter = 0
            def logPrefix(self):
                return 'FakeFD'
            def cb(self, rc, bytes, evt):
                self.counter += 1

        ir = IOCPReactor()
        fd = FakeFD()
        event = _iocp.Event(fd.cb, fd)
        for _ in range(EVENTS_PER_LOOP + 1):
            ir.port.postEvent(0, KEY_NORMAL, event)
        ir.doIteration(None)
        self.assertEqual(fd.counter, EVENTS_PER_LOOP)
        ir.doIteration(0)
        self.assertEqual(fd.counter, EVENTS_PER_LOOP + 1)