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

"""
Tests for the I{hosts(5)}-based resolver, L{twisted.names.hosts}.
"""

from __future__ import division, absolute_import

from twisted.trial.unittest import TestCase
from twisted.python.filepath import FilePath
from twisted.internet.defer import gatherResults

from twisted.names.dns import (
    A, AAAA, IN, DomainError, RRHeader, Query, Record_A, Record_AAAA)
from twisted.names.hosts import Resolver, searchFileFor, searchFileForAll


class GoodTempPathMixin(object):
    def path(self):
        return FilePath(self.mktemp().encode('utf-8'))



class SearchHostsFileTests(TestCase, GoodTempPathMixin):
    """
    Tests for L{searchFileFor}, a helper which finds the first address for a
    particular hostname in a I{hosts(5)}-style file.
    """
    def test_findAddress(self):
        """
        If there is an IPv4 address for the hostname passed to L{searchFileFor},
        it is returned.
        """
        hosts = self.path()
        hosts.setContent(
            b"10.2.3.4 foo.example.com\n")
        self.assertEqual(
            "10.2.3.4", searchFileFor(hosts.path, b"foo.example.com"))


    def test_notFoundAddress(self):
        """
        If there is no address information for the hostname passed to
        L{searchFileFor}, C{None} is returned.
        """
        hosts = self.path()
        hosts.setContent(
            b"10.2.3.4 foo.example.com\n")
        self.assertIs(None, searchFileFor(hosts.path, b"bar.example.com"))


    def test_firstAddress(self):
        """
        The first address associated with the given hostname is returned.
        """
        hosts = self.path()
        hosts.setContent(
            b"::1 foo.example.com\n"
            b"10.1.2.3 foo.example.com\n"
            b"fe80::21b:fcff:feee:5a1d foo.example.com\n")
        self.assertEqual("::1", searchFileFor(hosts.path, b"foo.example.com"))


    def test_searchFileForAliases(self):
        """
        For a host with a canonical name and one or more aliases,
        L{searchFileFor} can find an address given any of the names.
        """
        hosts = self.path()
        hosts.setContent(
            b"127.0.1.1\thelmut.example.org\thelmut\n"
            b"# a comment\n"
            b"::1 localhost ip6-localhost ip6-loopback\n")
        self.assertEqual(searchFileFor(hosts.path, b'helmut'), '127.0.1.1')
        self.assertEqual(
            searchFileFor(hosts.path, b'helmut.example.org'), '127.0.1.1')
        self.assertEqual(searchFileFor(hosts.path, b'ip6-localhost'), '::1')
        self.assertEqual(searchFileFor(hosts.path, b'ip6-loopback'), '::1')
        self.assertEqual(searchFileFor(hosts.path, b'localhost'), '::1')



class SearchHostsFileForAllTests(TestCase, GoodTempPathMixin):
    """
    Tests for L{searchFileForAll}, a helper which finds all addresses for a
    particular hostname in a I{hosts(5)}-style file.
    """
    def test_allAddresses(self):
        """
        L{searchFileForAll} returns a list of all addresses associated with the
        name passed to it.
        """
        hosts = self.path()
        hosts.setContent(
            b"127.0.0.1     foobar.example.com\n"
            b"127.0.0.2     foobar.example.com\n"
            b"::1           foobar.example.com\n")
        self.assertEqual(
            ["127.0.0.1", "127.0.0.2", "::1"],
            searchFileForAll(hosts, b"foobar.example.com"))


    def test_caseInsensitively(self):
        """
        L{searchFileForAll} searches for names case-insensitively.
        """
        hosts = self.path()
        hosts.setContent(b"127.0.0.1     foobar.EXAMPLE.com\n")
        self.assertEqual(
            ["127.0.0.1"], searchFileForAll(hosts, b"FOOBAR.example.com"))


    def test_readError(self):
        """
        If there is an error reading the contents of the hosts file,
        L{searchFileForAll} returns an empty list.
        """
        self.assertEqual(
            [], searchFileForAll(self.path(), b"example.com"))



class HostsTestCase(TestCase, GoodTempPathMixin):
    """
    Tests for the I{hosts(5)}-based L{twisted.names.hosts.Resolver}.
    """
    def setUp(self):
        f = self.path()
        f.setContent(b'''
1.1.1.1    EXAMPLE EXAMPLE.EXAMPLETHING
::2        mixed
1.1.1.2    MIXED
::1        ip6thingy
1.1.1.3    multiple
1.1.1.4    multiple
::3        ip6-multiple
::4        ip6-multiple
''')
        self.ttl = 4200
        self.resolver = Resolver(f.path, self.ttl)


    def test_defaultPath(self):
        """
        The default hosts file used by L{Resolver} is I{/etc/hosts} if no value
        is given for the C{file} initializer parameter.
        """
        resolver = Resolver()
        self.assertEqual(b"/etc/hosts", resolver.file)


    def test_getHostByName(self):
        """
        L{hosts.Resolver.getHostByName} returns a L{Deferred} which fires with a
        string giving the address of the queried name as found in the resolver's
        hosts file.
        """
        data = [(b'EXAMPLE', '1.1.1.1'),
                (b'EXAMPLE.EXAMPLETHING', '1.1.1.1'),
                (b'MIXED', '1.1.1.2'),
                ]
        ds = [self.resolver.getHostByName(n).addCallback(self.assertEqual, ip)
              for n, ip in data]
        return gatherResults(ds)


    def test_lookupAddress(self):
        """
        L{hosts.Resolver.lookupAddress} returns a L{Deferred} which fires with A
        records from the hosts file.
        """
        d = self.resolver.lookupAddress(b'multiple')
        def resolved(results):
            answers, authority, additional = results
            self.assertEqual(
                (RRHeader(b"multiple", A, IN, self.ttl,
                          Record_A("1.1.1.3", self.ttl)),
                 RRHeader(b"multiple", A, IN, self.ttl,
                          Record_A("1.1.1.4", self.ttl))),
                answers)
        d.addCallback(resolved)
        return d


    def test_lookupIPV6Address(self):
        """
        L{hosts.Resolver.lookupIPV6Address} returns a L{Deferred} which fires
        with AAAA records from the hosts file.
        """
        d = self.resolver.lookupIPV6Address(b'ip6-multiple')
        def resolved(results):
            answers, authority, additional = results
            self.assertEqual(
                (RRHeader(b"ip6-multiple", AAAA, IN, self.ttl,
                          Record_AAAA("::3", self.ttl)),
                 RRHeader(b"ip6-multiple", AAAA, IN, self.ttl,
                          Record_AAAA("::4", self.ttl))),
                answers)
        d.addCallback(resolved)
        return d


    def test_lookupAllRecords(self):
        """
        L{hosts.Resolver.lookupAllRecords} returns a L{Deferred} which fires
        with A records from the hosts file.
        """
        d = self.resolver.lookupAllRecords(b'mixed')
        def resolved(results):
            answers, authority, additional = results
            self.assertEqual(
                (RRHeader(b"mixed", A, IN, self.ttl,
                          Record_A("1.1.1.2", self.ttl)),),
                answers)
        d.addCallback(resolved)
        return d


    def testNotImplemented(self):
        return self.assertFailure(self.resolver.lookupMailExchange(b'EXAMPLE'),
                                  NotImplementedError)


    def testQuery(self):
        d = self.resolver.query(Query(b'EXAMPLE'))
        d.addCallback(lambda x: self.assertEqual(x[0][0].payload.dottedQuad(),
                                                 '1.1.1.1'))
        return d


    def test_lookupAddressNotFound(self):
        """
        L{hosts.Resolver.lookupAddress} returns a L{Deferred} which fires with
        L{dns.DomainError} if the name passed in has no addresses in the hosts
        file.
        """
        return self.assertFailure(self.resolver.lookupAddress(b'foueoa'),
                                  DomainError)


    def test_lookupIPV6AddressNotFound(self):
        """
        Like L{test_lookupAddressNotFound}, but for
        L{hosts.Resolver.lookupIPV6Address}.
        """
        return self.assertFailure(self.resolver.lookupIPV6Address(b'foueoa'),
                                  DomainError)


    def test_lookupAllRecordsNotFound(self):
        """
        Like L{test_lookupAddressNotFound}, but for
        L{hosts.Resolver.lookupAllRecords}.
        """
        return self.assertFailure(self.resolver.lookupAllRecords(b'foueoa'),
                                  DomainError)
