#!/usr/bin/env python

###
# Copyright (c) 2002, Jeremiah Fincher
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
#   * Redistributions in binary form must reproduce the above copyright notice,
#     this list of conditions, and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
###

__revision__ = "$Id$"

import fix

import os
import sets
import time
import string
from itertools import imap, ilen, ifilter

import log
import conf
import utils
import world
import ircutils
import unpreserve

def fromChannelCapability(capability):
    """Returns a (channel, capability) tuple from a channel capability."""
    assert isChannelCapability(capability)
    return capability.split(',', 1)

def isChannelCapability(capability):
    """Returns True if capability is a channel capability; False otherwise."""
    if ',' in capability:
        (channel, capability) = capability.split(',', 1)
        return ircutils.isChannel(channel)
    else:
        return False

def makeChannelCapability(channel, capability):
    """Makes a channel capability given a channel and a capability."""
    return '%s,%s' % (channel, capability)

def isAntiCapability(capability):
    """Returns True if capability is an anticapability; False otherwise."""
    if isChannelCapability(capability):
        (_, capability) = fromChannelCapability(capability)
    return capability and capability[0] == '-'

def makeAntiCapability(capability):
    """Returns the anticapability of a given capability."""
    assert not isAntiCapability(capability), 'makeAntiCapability does not ' \
           'work on anticapabilities; you probably want invertCapability.'
    if isChannelCapability(capability):
        (channel, capability) = fromChannelCapability(capability)
        return makeChannelCapability(channel, '-' + capability)
    else:
        return '-' + capability

def unAntiCapability(capability):
    """Takes an anticapability and returns the non-anti form."""
    if not isAntiCapability(capability):
        raise ValueError, '%s is not an anti capability' % capability
    if isChannelCapability(capability):
        (channel, capability) = fromChannelCapability(capability)
        return ','.join((channel, capability[1:]))
    else:
        return capability[1:]

def invertCapability(capability):
    """Make a capability into an anticapability and vice versa."""
    if isAntiCapability(capability):
        return unAntiCapability(capability)
    else:
        return makeAntiCapability(capability)

_normal = string.maketrans('\r\n', '  ')
def _normalize(s):
    return s.translate(_normal)


_invert = invertCapability
class CapabilitySet(sets.Set):
    """A subclass of set handling basic capability stuff."""
    def __init__(self, capabilities=()):
        self.__parent = super(CapabilitySet, self)
        self.__parent.__init__()
        for capability in capabilities:
            self.add(capability)

    def add(self, capability):
        """Adds a capability to the set."""
        capability = ircutils.toLower(capability)
        inverted = _invert(capability)
        if self.__parent.__contains__(inverted):
            self.__parent.remove(inverted)
        self.__parent.add(capability)

    def remove(self, capability):
        """Removes a capability from the set."""
        capability = ircutils.toLower(capability)
        self.__parent.remove(capability)

    def __contains__(self, capability):
        capability = ircutils.toLower(capability)
        if self.__parent.__contains__(capability):
            return True
        if self.__parent.__contains__(_invert(capability)):
            return True
        else:
            return False

    def check(self, capability):
        """Returns the appropriate boolean for whether a given capability is
        'allowed' given its (or its anticapability's) presence in the set.
        """
        capability = ircutils.toLower(capability)
        if self.__parent.__contains__(capability):
            return True
        elif self.__parent.__contains__(_invert(capability)):
            return False
        else:
            raise KeyError, capability

    def __repr__(self):
        return '%s([%s])' % (self.__class__.__name__,
                             ', '.join(imap(repr, self)))

antiOwner = makeAntiCapability('owner')
class UserCapabilitySet(CapabilitySet):
    """A subclass of CapabilitySet to handle the owner capability correctly."""
    def __init__(self, *args, **kwargs):
        self.__parent = super(UserCapabilitySet, self)
        self.__parent.__init__(*args, **kwargs)
        
    def __contains__(self, capability):
        capability = ircutils.toLower(capability)
        if capability == 'owner' or capability == antiOwner:
            return True
        elif self.__parent.__contains__('owner'):
            return True
        else:
            return self.__parent.__contains__(capability)

    def check(self, capability):
        """Returns the appropriate boolean for whether a given capability is
        'allowed' given its (or its anticapability's) presence in the set.
        Differs from CapabilitySet in that it handles the 'owner' capability
        appropriately.
        """
        capability = ircutils.toLower(capability)
        if capability == 'owner' or capability == antiOwner:
            if self.__parent.__contains__('owner'):
                return not isAntiCapability(capability)
            else:
                return isAntiCapability(capability)
        elif self.__parent.__contains__('owner'):
            if isAntiCapability(capability):
                return False
            else:
                return True
        else:
            return self.__parent.check(capability)

    def add(self, capability):
        """Adds a capability to the set.  Just make sure it's not -owner."""
        capability = ircutils.toLower(capability)
        assert capability != '-owner', '"-owner" disallowed.'
        self.__parent.add(capability)

class IrcUser(object):
    """This class holds the capabilities and authentications for a user."""
    def __init__(self, ignore=False, password='', name='',
                 capabilities=(), hostmasks=None, secure=False, hashed=False):
        self.auth = None # The (time, hostmask) a user authenticated under
        self.name = name # The name of the user.
        self.ignore = ignore # A boolean deciding if the person is ignored.
        self.secure = secure # A boolean describing if hostmasks *must* match.
        self.hashed = hashed # True if the password is hashed on disk.
        self.password = password # password (plaintext? hashed?)
        self.capabilities = UserCapabilitySet()
        for capability in capabilities:
            self.capabilities.add(capability)
        if hostmasks is None:
            self.hostmasks = [] # A list of hostmasks used for recognition
        else:
            self.hostmasks = hostmasks

    def __repr__(self):
        return '%s(ignore=%s, password=%r, name=%r, hashed=%r, ' \
               'capabilities=%r, hostmasks=%r, secure=%r)\n' % \
               (self.__class__.__name__,
                self.ignore, self.password, self.name, self.hashed,
                self.capabilities, self.hostmasks, self.secure)

    def addCapability(self, capability):
        """Gives the user the given capability."""
        self.capabilities.add(capability)

    def removeCapability(self, capability):
        """Takes from the user the given capability."""
        self.capabilities.remove(capability)

    def checkCapability(self, capability):
        """Checks the user for a given capability."""
        if self.ignore:
            if isAntiCapability(capability):
                return True
            else:
                return False
        else:
            return self.capabilities.check(capability)

    def setPassword(self, password, hashed=False):
        """Sets the user's password."""
        if hashed or self.hashed:
            self.hashed = True
            self.password = utils.saltHash(password)
        else:
            self.password = password

    def checkPassword(self, password):
        """Checks the user's password."""
        if self.hashed:
            (salt, _) = self.password.split('|')
            return (self.password == utils.saltHash(password, salt=salt))
        else:
            return (self.password == password)

    def checkHostmask(self, hostmask, useAuth=True):
        """Checks a given hostmask against the user's hostmasks or current
        authentication.  If useAuth is False, only checks against the user's
        hostmasks.
        """
        if useAuth and self.auth and (hostmask == self.auth[1]):
            return True
        for pat in self.hostmasks:
            if ircutils.hostmaskPatternEqual(pat, hostmask):
                return True
        return False

    def addHostmask(self, hostmask):
        """Adds a hostmask to the user's hostmasks."""
        self.hostmasks.append(hostmask)

    def removeHostmask(self, hostmask):
        """Removes a hostmask from the user's hostmasks."""
        self.hostmasks = [s for s in self.hostmasks if s != hostmask]

    def setAuth(self, hostmask):
        """Sets a user's authenticated hostmask.  This times out in 1 hour."""
        if self.checkHostmask(hostmask, useAuth=False) or not self.secure:
            self.auth = (time.time(), hostmask)
        else:
            raise ValueError, 'secure flag set, unmatched hostmask'

    def unsetAuth(self):
        """Unsets a use's authenticated hostmask."""
        self.auth = None

    def preserve(self, fd, indent=''):
        def write(s):
            fd.write(indent)
            fd.write(s)
            fd.write(os.linesep)
        write('name %s' % self.name)
        write('ignore %s' % self.ignore)
        write('secure %s' % self.secure)
        write('hashed %s' % self.hashed)
        write('password %s' % self.password)
        for capability in self.capabilities:
            write('capability %s' % capability)
        for hostmask in self.hostmasks:
            write('hostmask %s' % hostmask)
        fd.write(os.linesep)


class IrcChannel(object):
    """This class holds the capabilities, bans, and ignores of a channel.
    """
    defaultOff = ('op', 'halfop', 'voice', 'protected')
    def __init__(self, bans=None, ignores=None, capabilities=None,
                 lobotomized=False, defaultAllow=True):
        self.defaultAllow = defaultAllow
        if bans is None:
            self.bans = []
        else:
            self.bans = bans
        if ignores is None:
            self.ignores = []
        else:
            self.ignores = ignores
        if capabilities is None:
            self.capabilities = CapabilitySet()
        else:
            self.capabilities = capabilities
        for capability in self.defaultOff:
            if capability not in self.capabilities:
                self.capabilities.add(makeAntiCapability(capability))
        self.lobotomized = lobotomized

    def __repr__(self):
        return '%s(bans=%r, ignores=%r, capabilities=%r, ' \
               'lobotomized=%r, defaultAllow=%s)\n' % \
               (self.__class__.__name__, self.bans, self.ignores,
                self.capabilities, self.lobotomized,
                self.defaultAllow)

    def addBan(self, hostmask):
        """Adds a ban to the channel banlist."""
        self.bans.append(hostmask)

    def removeBan(self, hostmask):
        """Removes a ban from the channel banlist."""
        self.bans = [s for s in self.bans if s != hostmask]

    def checkBan(self, hostmask):
        """Checks whether a given hostmask is banned by the channel banlist."""
        for pat in self.bans:
            if ircutils.hostmaskPatternEqual(pat, hostmask):
                return True
        return False

    def addIgnore(self, hostmask):
        """Adds an ignore to the channel ignore list."""
        self.ignores.append(hostmask)

    def removeIgnore(self, hostmask):
        """Removes an ignore from the channel ignore list."""
        self.ignores = [s for s in self.ignores if s != hostmask]

    def addCapability(self, capability):
        """Adds a capability to the channel's default capabilities."""
        self.capabilities.add(capability)

    def removeCapability(self, capability):
        """Removes a capability from the channel's default capabilities."""
        self.capabilities.remove(capability)

    def setDefaultCapability(self, b):
        """Sets the default capability in the channel."""
        self.defaultAllow = b

    def checkCapability(self, capability):
        """Checks whether a certain capability is allowed by the channel."""
        if capability in self.capabilities:
            return self.capabilities.check(capability)
        else:
            if isAntiCapability(capability):
                return not self.defaultAllow
            else:
                return self.defaultAllow

    def checkIgnored(self, hostmask):
        """Checks whether a given hostmask is to be ignored by the channel."""
        if self.lobotomized:
            return True
        for mask in self.bans:
            if ircutils.hostmaskPatternEqual(mask, hostmask):
                return True
        for mask in self.ignores:
            if ircutils.hostmaskPatternEqual(mask, hostmask):
                return True
        return False

    def preserve(self, fd, indent=''):
        def write(s):
            fd.write(indent)
            fd.write(s)
            fd.write(os.linesep)
        write('lobotomized %s' % self.lobotomized)
        write('defaultAllow %s' % self.defaultAllow)
        for ban in self.bans:
            write('ban %s' % ban)
        for ignore in self.ignores:
            write('ignore %s' % ignore)
        for capability in self.capabilities:
            write('capability %s' % capability)
        fd.write(os.linesep)
        

class Creator(object):
    def badCommand(self, command, rest, lineno):
        raise ValueError, 'Invalid command on line %s: %s' % (lineno, command)
    
class IrcUserCreator(Creator):
    id = None
    def __init__(self):
        self.u = IrcUser()

    def user(self, rest, lineno):
        if self.id is not None:
            raise ValueError, 'Unexpected user command on line %s.' % lineno
        IrcUserCreator.id = int(rest)

    def name(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.name = rest

    def ignore(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.ignore = bool(eval(rest))

    def secure(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.secure = bool(eval(rest))

    def hashed(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.hashed = bool(eval(rest))

    def password(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.password = rest

    def hostmask(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.hostmasks.append(rest)

    def capability(self, rest, lineno):
        if self.id is None:
            raise ValueError, 'Unexpected user description without id.'
        self.u.capabilities.add(rest)

    def finish(self):
        if self.u.name:
            users.setUser(self.id, self.u)
            IrcUserCreator.id = None

class IrcChannelCreator(Creator):
    name = None
    def __init__(self):
        self.c = IrcChannel()
        self.hadChannel = bool(self.name)

    def channel(self, rest, lineno):
        if self.name is not None:
            raise ValueError, 'Unexpected channel command on line %s' % lineno
        IrcChannelCreator.name = rest

    def lobotomized(self, rest, lineno):
        if self.name is None:
            raise ValueError, 'Unexpected channel description without channel.'
        self.c.lobotomized = bool(eval(rest))
    
    def defaultallow(self, rest, lineno):
        if self.name is None:
            raise ValueError, 'Unexpected channel description without channel.'
        self.c.defaultAllow = bool(eval(rest))

    def capability(self, rest, lineno):
        if self.name is None:
            raise ValueError, 'Unexpected channel description without channel.'
        self.c.capabilities.add(rest)

    def ban(self, rest, lineno):
        if self.name is None:
            raise ValueError, 'Unexpected channel description without channel.'
        self.c.bans.append(rest)

    def ignore(self, rest, lineno):
        if self.name is None:
            raise ValueError, 'Unexpected channel description without channel.'
        self.c.ignores.append(rest)

    def finish(self):
        if self.hadChannel:
            channels.setChannel(self.name, self.c)
            IrcChannelCreator.name = None
    

class UsersDictionary(utils.IterableMap):
    """A simple serialized-to-file User Database."""
    def __init__(self):
        self.filename = None
        self.users = {}
        self.nextId = 1
        self._nameCache = {}
        self._hostmaskCache = {}

    # This is separate because the Creator has to access our instance.
    def open(self, filename):
        self.filename = filename
        reader = unpreserve.Reader(IrcUserCreator)
        reader.readFile(filename)

    def reload(self):
        """Reloads the database from its file."""
        if self.filename is not None:
            self.nextId = 1
            self.users.clear()
            try:
                self.open(self.filename)
            except EnvironmentError, e:
                log.warning('UsersDictionary.reload failed: %s', e)
        else:
            log.warning('UsersDictionary.reload called with no filename.')

    def flush(self):
        """Flushes the database to its file."""
        if self.filename is not None:
            L = self.users.items()
            L.sort()
            fd = file(self.filename, 'w')
            for (id, u) in L:
                fd.write('user %s' % id)
                fd.write(os.linesep)
                u.preserve(fd, indent='  ')
            fd.close()
        else:
            log.warning('UsersDictionary.flush called with no filename.')

    def iteritems(self):
        return self.users.iteritems()

    def getUserId(self, s):
        """Returns the user ID of a given name or hostmask."""
        if ircutils.isUserHostmask(s):
            try:
                return self._hostmaskCache[s]
            except KeyError:
                ids = []
                for (id, user) in self.users.iteritems():
                    if user.checkHostmask(s):
                        ids.append(id)
                if len(ids) == 1:
                    id = ids[0]
                    self._hostmaskCache[s] = id
                    try:
                        self._hostmaskCache[id].add(s)
                    except KeyError:
                        self._hostmaskCache[id] = sets.Set([s])
                    return id
                elif len(ids) == 0:
                    raise KeyError, s
                else:
                    raise ValueError, 'Ids %r matched.' % ids
        else: # Not a hostmask, must be a name.
            s = s.lower()
            try:
                return self._nameCache[s]
            except KeyError:
                for (id, user) in self.users.items():
                    if s == user.name.lower():
                        self._nameCache[s] = id
                        self._nameCache[id] = s
                        return id
                else:
                    raise KeyError, s

    def getUser(self, id):
        """Returns a user given its id, name, or hostmask."""
        if not isinstance(id, int):
            # Must be a string.  Get the UserId first.
            id = self.getUserId(id)
        return self.users[id]

    def hasUser(self, id):
        """Returns the database has a user given its id, name, or hostmask."""
        try:
            self.getUser(id)
            return True
        except KeyError:
            return False

    def numUsers(self):
        return len(self.users)

    def setUser(self, id, user):
        """Sets a user (given its id) to the IrcUser given it."""
        assert isinstance(id, int), 'setUser takes an integer userId.'
        self.nextId = max(self.nextId, id)
        try:
            if self.getUserId(user.name) != id:
                s = '%s is already registered to someone else.' % user.name
                raise ValueError, s
        except KeyError:
            pass
        for hostmask in user.hostmasks:
            try:
                if self.getUserId(hostmask) != id:
                    s = '%s is already registered to someone else.'% hostmask
                    raise ValueError, s
            except KeyError:
                continue
        if id in self._nameCache:
            del self._nameCache[self._nameCache[id]]
            del self._nameCache[id]
        if id in self._hostmaskCache:
            for hostmask in self._hostmaskCache[id]:
                del self._hostmaskCache[hostmask]
            del self._hostmaskCache[id]
        self.users[id] = user
        self.flush()

    def delUser(self, id):
        """Removes a user from the database."""
        del self.users[id]
        if id in self._nameCache:
            del self._nameCache[self._nameCache[id]]
            del self._nameCache[id]
        if id in self._hostmaskCache:
            for hostmask in self._hostmaskCache[id]:
                del self._hostmaskCache[hostmask]
            del self._hostmaskCache[id]
        self.flush()

    def newUser(self):
        """Allocates a new user in the database and returns it and its id."""
        user = IrcUser()
        id = self.nextId
        self.nextId += 1
        self.users[id] = user
        self.flush()
        return (id, user)
    


class ChannelsDictionary(utils.IterableMap):
    def __init__(self):
        self.filename = None
        self.channels = ircutils.IrcDict()

    def open(self, filename):
        self.filename = filename
        reader = unpreserve.Reader(IrcChannelCreator)
        reader.readFile(filename)

    def flush(self):
        """Flushes the channel database to its file."""
        if self.filename is not None:
            fd = file(self.filename, 'w')
            for (channel, c) in self.channels.iteritems():
                fd.write('channel %s' % channel)
                fd.write(os.linesep)
                c.preserve(fd, indent='  ')
            fd.close()
        else:
            log.warning('ChannelsDictionary.flush without self.filename.')

    def reload(self):
        """Reloads the channel database from its file."""
        if self.filename is not None:
            self.channels.clear()
            try:
                self.open(self.filename)
            except EnvironmentError, e:
                log.warning('ChannelsDictionary.reload failed: %s', e)
        else:
            log.warning('ChannelsDictionary.reload without self.filename.')

    def getChannel(self, channel):
        """Returns an IrcChannel object for the given channel."""
        channel = channel.lower()
        if channel in self.channels:
            return self.channels[channel]
        else:
            c = IrcChannel()
            self.channels[channel] = c
            return c

    def setChannel(self, channel, ircChannel):
        """Sets a given channel to the IrcChannel object given."""
        channel = channel.lower()
        self.channels[channel] = ircChannel
        self.flush()

    def iteritems(self):
        return self.channels.iteritems()


class IgnoresDB(object):
    def __init__(self):
        self.filename = None
        self.hostmasks = sets.Set()

    def open(self, filename):
        self.filename = filename
        fd = file(self.filename)
        for line in utils.nonCommentNonEmptyLines(fd):
            self.hostmasks.add(line.rstrip('\r\n'))
        fd.close()

    def flush(self):
        if self.filename is not None:
            fd = file(self.filename, 'w')
            for hostmask in self.hostmasks:
                fd.write(hostmask)
                fd.write(os.linesep)
            fd.close()
        else:
            log.warning('IgnoresDB.flush called without self.filename.')

    def reload(self):
        if self.filename is not None:
            self.hostmasks.clear()
            try:
                self.open(self.filename)
            except EnvironmentError, e:
                log.warning('IgnoresDB.reload failed: %s', e)
        else:
            log.warning('IgnoresDB.reload called without self.filename.')
        
    def checkIgnored(self, prefix):
        for hostmask in self.hostmasks:
            if ircutils.hostmaskPatternEqual(hostmask, prefix):
                return True
        return False

    def addHostmask(self, hostmask):
        self.hostmasks.add(hostmask)

    def removeHostmask(self, hostmask):
        self.hostmasks.remove(hostmask)


confDir = conf.supybot.directories.conf()
try:
    userFile = os.path.join(confDir, conf.supybot.databases.users.filename())
    users = UsersDictionary()
    users.open(userFile)
except EnvironmentError, e:
    log.warning('Couldn\'t open user database: %s', e)

try:
    channelFile = os.path.join(confDir,
                               conf.supybot.databases.channels.filename())
    channels = ChannelsDictionary()
    channels.open(channelFile)
except EnvironmentError, e:
    log.warning('Couldn\'t open channel database: %s', e)

try:
    ignoreFile = os.path.join(confDir,
                              conf.supybot.databases.ignores.filename())
    ignores = IgnoresDB()
    ignores.open(ignoreFile)
except EnvironmentError, e:
    log.warning('Couldn\'t open ignore database: %s', e)


world.flushers.append(users.flush)
world.flushers.append(ignores.flush)
world.flushers.append(channels.flush)
    

###
# Useful functions for checking credentials.
###
def checkIgnored(hostmask, recipient='', users=users, channels=channels):
    """checkIgnored(hostmask, recipient='') -> True/False

    Checks if the user is ignored by the recipient of the message.
    """
    if ignores.checkIgnored(hostmask):
        log.debug('Ignoring %s due to ignore database.', hostmask)
        return True
    try:
        id = users.getUserId(hostmask)
        user = users.getUser(id)
    except KeyError:
        # If there's no user...
        if ircutils.isChannel(recipient):
            channel = channels.getChannel(recipient)
            if channel.checkIgnored(hostmask):
                log.debug('Ignoring %s due to the channel ignores.', hostmask)
                return True
            else:
                return False
        else:
            if conf.supybot.defaultIgnore():
                log.debug('Ignoring %s due to conf.supybot.defaultIgnore',
                         hostmask)
                return True
            else:
                return False
    if user.checkCapability('owner'):
        # Owners shouldn't ever be ignored.
        return False
    elif user.ignore:
        log.debug('Ignoring %s due to his IrcUser ignore flag.', hostmask)
        return True
    elif recipient:
        if ircutils.isChannel(recipient):
            channel = channels.getChannel(recipient)
            if channel.checkIgnored(hostmask):
                log.debug('Ignoring %s due to the channel ignores.', hostmask)
                return True
            else:
                return False
        else:
            return False
    else:
        return False

def _x(capability, ret):
    if isAntiCapability(capability):
        return not ret
    else:
        return ret

def _checkCapabilityForUnknownUser(capability, users=users, channels=channels):
    if isChannelCapability(capability):
        (channel, capability) = fromChannelCapability(capability)
        try:
            c = channels.getChannel(channel)
            if capability in c.capabilities:
                return c.checkCapability(capability)
            else:
                return _x(capability, c.defaultAllow)
        except KeyError:
            pass
    if capability in conf.supybot.defaultCapabilities():
        return True
    elif invertCapability(capability) in conf.supybot.defaultCapabilities():
        return False
    else:
        return _x(capability, conf.supybot.defaultAllow())

def checkCapability(hostmask, capability, users=users, channels=channels):
    """Checks that the user specified by name/hostmask has the capabilty given.
    """
    if world.testing:
        return _x(capability, True)
    try:
        u = users.getUser(hostmask)
        if u.secure and not u.checkHostmask(hostmask, useAuth=False):
            raise KeyError
    except KeyError:
        # Raised when no hostmasks match.
        return _checkCapabilityForUnknownUser(capability, users=users,
                                              channels=channels)
    except ValueError, e:
        # Raised when multiple hostmasks match.
        log.warning('%s: %s', hostmask, e)
        return _checkCapabilityForUnknownUser(capability, users=users,
                                              channels=channels)
    if capability in u.capabilities:
        return u.checkCapability(capability)
    else:
        if isChannelCapability(capability):
            (channel, capability) = fromChannelCapability(capability)
            try:
                chanop = makeChannelCapability(channel, 'op')
                if u.checkCapability(chanop):
                    return _x(capability, True)
            except KeyError:
                pass
            c = channels.getChannel(channel)
            if capability in c.capabilities:
                return c.checkCapability(capability)
            else:
                return _x(capability, c.defaultAllow)
        defaultCapabilities = conf.supybot.defaultCapabilities()
        if capability in defaultCapabilities:
            return True
        elif invertCapability(capability) in defaultCapabilities:
            return False
        else:
            return _x(capability, conf.supybot.defaultAllow())


def checkCapabilities(hostmask, capabilities, requireAll=False):
    """Checks that a user has capabilities in a list.

    requireAll is the True if *all* capabilities in the list must be had, False
    if *any* of the capabilities in the list must be had.
    """
    for capability in capabilities:
        if requireAll:
            if not checkCapability(hostmask, capability):
                return False
        else:
            if checkCapability(hostmask, capability):
                return True
    if requireAll:
        return True
    else:
        return False


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