# Authors:
#   Nathaniel McCallum <npmccallum@redhat.com>
#
# Copyright (C) 2013  Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from ipalib.plugins.baseldap import DN, LDAPObject, LDAPAddMember, LDAPRemoveMember
from ipalib.plugins.baseldap import LDAPCreate, LDAPDelete, LDAPUpdate, LDAPSearch, LDAPRetrieve
from ipalib import api, Int, Str, Bool, DateTime, Flag, Bytes, IntEnum, StrEnum, Password, _, ngettext
from ipalib.plugable import Registry
from ipalib.errors import PasswordMismatch, ConversionError, LastMemberError, NotFound, ValidationError
from ipalib.request import context
from ipalib.frontend import Local

from backports.ssl_match_hostname import match_hostname
import base64
import uuid
import urllib
import urllib2
import httplib
import urlparse
import qrcode
import os
import ssl

__doc__ = _("""
OTP Tokens
""") + _("""
Manage OTP tokens.
""") + _("""
IPA supports the use of OTP tokens for multi-factor authentication. This
code enables the management of OTP tokens.
""") + _("""
EXAMPLES:
""") + _("""
 Add a new token:
   ipa otptoken-add --type=totp --owner=jdoe --desc="My soft token"
""") + _("""
 Examine the token:
   ipa otptoken-show a93db710-a31a-4639-8647-f15b2c70b78a
""") + _("""
 Change the vendor:
   ipa otptoken-mod a93db710-a31a-4639-8647-f15b2c70b78a --vendor="Red Hat"
""") + _("""
 Delete a token:
   ipa otptoken-del a93db710-a31a-4639-8647-f15b2c70b78a
""")

register = Registry()

TOKEN_TYPES = {
    u'totp': ['ipatokentotpclockoffset', 'ipatokentotptimestep'],
    u'hotp': ['ipatokenhotpcounter']
}

# NOTE: For maximum compatibility, KEY_LENGTH % 5 == 0
KEY_LENGTH = 20

class OTPTokenKey(Bytes):
    """A binary password type specified in base32."""

    password = True

    kwargs = Bytes.kwargs + (
        ('confirm', bool, True),
    )

    def _convert_scalar(self, value, index=None):
        if isinstance(value, (tuple, list)) and len(value) == 2:
            (p1, p2) = value
            if p1 != p2:
                raise PasswordMismatch(name=self.name, index=index)
            value = p1

        if isinstance(value, unicode):
            try:
                value = base64.b32decode(value, True)
            except TypeError, e:
                raise ConversionError(name=self.name, index=index, error=str(e))

        return super(OTPTokenKey, self)._convert_scalar(value, index)

def _convert_owner(userobj, entry_attrs, options):
    if 'ipatokenowner' in entry_attrs and not options.get('raw', False):
        entry_attrs['ipatokenowner'] = map(userobj.get_primary_key_from_dn,
                                           entry_attrs['ipatokenowner'])

def _normalize_owner(userobj, entry_attrs):
    owner = entry_attrs.get('ipatokenowner', None)
    if owner is not None:
        entry_attrs['ipatokenowner'] = userobj.get_dn(owner)

def _check_interval(not_before, not_after):
    if not_before and not_after:
        return not_before <= not_after
    return True


@register()
class otptoken(LDAPObject):
    """
    OTP Token object.
    """
    container_dn = api.env.container_otp
    object_name = _('OTP token')
    object_name_plural = _('OTP tokens')
    object_class = ['ipatoken']
    possible_objectclasses = ['ipatokentotp', 'ipatokenhotp']
    default_attributes = [
        'ipatokenuniqueid', 'description', 'ipatokenowner',
        'ipatokendisabled', 'ipatokennotbefore', 'ipatokennotafter',
        'ipatokenvendor', 'ipatokenmodel', 'ipatokenserial', 'managedby'
    ]
    attribute_members = {
        'managedby': ['user'],
    }
    relationships = {
        'managedby': ('Managed by', 'man_by_', 'not_man_by_'),
    }
    rdn_is_primary_key = True

    label = _('OTP Tokens')
    label_singular = _('OTP Token')

    takes_params = (
        Str('ipatokenuniqueid',
            cli_name='id',
            label=_('Unique ID'),
            primary_key=True,
            flags=('optional_create'),
        ),
        StrEnum('type?',
            label=_('Type'),
            default=u'totp',
            autofill=True,
            values=tuple(TOKEN_TYPES.keys()),
            flags=('virtual_attribute', 'no_update'),
        ),
        Str('description?',
            cli_name='desc',
            label=_('Description'),
        ),
        Str('ipatokenowner?',
            cli_name='owner',
            label=_('Owner'),
        ),
        Str('managedby_user?',
            label=_('Manager'),
            flags=['no_create', 'no_update', 'no_search'],
        ),
        Bool('ipatokendisabled?',
            cli_name='disabled',
            label=_('Disabled state')
        ),
        DateTime('ipatokennotbefore?',
            cli_name='not_before',
            label=_('Validity start'),
        ),
        DateTime('ipatokennotafter?',
            cli_name='not_after',
            label=_('Validity end'),
        ),
        Str('ipatokenvendor?',
            cli_name='vendor',
            label=_('Vendor'),
            default=u'FreeIPA',
            autofill=True,
        ),
        Str('ipatokenmodel?',
            cli_name='model',
            label=_('Model'),
            default_from=lambda type: type,
            autofill=True,
        ),
        Str('ipatokenserial?',
            cli_name='serial',
            label=_('Serial'),
            default_from=lambda id: id,
            autofill=True,
        ),
        OTPTokenKey('ipatokenotpkey?',
            cli_name='key',
            label=_('Key'),
            default_from=lambda: os.urandom(KEY_LENGTH),
            autofill=True,
            flags=('no_display', 'no_update', 'no_search'),
        ),
        StrEnum('ipatokenotpalgorithm?',
            cli_name='algo',
            label=_('Algorithm'),
            default=u'sha1',
            autofill=True,
            flags=('no_update'),
            values=(u'sha1', u'sha256', u'sha384', u'sha512'),
        ),
        IntEnum('ipatokenotpdigits?',
            cli_name='digits',
            label=_('Digits'),
            values=(6, 8),
            default=6,
            autofill=True,
            flags=('no_update'),
        ),
        Int('ipatokentotpclockoffset?',
            cli_name='offset',
            label=_('Clock offset'),
            default=0,
            autofill=True,
            flags=('no_update'),
        ),
        Int('ipatokentotptimestep?',
            cli_name='interval',
            label=_('Clock interval'),
            default=30,
            autofill=True,
            minvalue=5,
            flags=('no_update'),
        ),
        Int('ipatokenhotpcounter?',
            cli_name='counter',
            label=_('Counter'),
            default=0,
            autofill=True,
            minvalue=0,
            flags=('no_update'),
        ),
    )


@register()
class otptoken_add(LDAPCreate):
    __doc__ = _('Add a new OTP token.')
    msg_summary = _('Added OTP token "%(value)s"')

    takes_options = LDAPCreate.takes_options + (
        Flag('qrcode?', label=_('Display QR code (requires wide terminal)')),
    )

    has_output_params = LDAPCreate.has_output_params + (
        Str('uri?', label=_('URI')),
    )

    def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
        # Fill in a default UUID when not specified.
        if entry_attrs.get('ipatokenuniqueid', None) is None:
            entry_attrs['ipatokenuniqueid'] = str(uuid.uuid4())
            dn = DN("ipatokenuniqueid=%s" % entry_attrs['ipatokenuniqueid'], dn)

        if not _check_interval(options.get('ipatokennotbefore', None),
                               options.get('ipatokennotafter', None)):
            raise ValidationError(name='not_after',
                                  error='is before the validity start')

        # Set the object class and defaults for specific token types
        entry_attrs['objectclass'] = otptoken.object_class + ['ipatoken' + options['type']]
        for ttype, tattrs in TOKEN_TYPES.items():
            if ttype != options['type']:
                for tattr in tattrs:
                    if tattr in entry_attrs:
                        del entry_attrs[tattr]

        # If owner was not specified, default to the person adding this token.
        # If managedby was not specified, attempt a sensible default.
        if 'ipatokenowner' not in entry_attrs or 'managedby' not in entry_attrs:
            result = self.api.Command.user_find(whoami=True)['result']
            if result:
                cur_uid = result[0]['uid'][0]
                prev_uid = entry_attrs.setdefault('ipatokenowner', cur_uid)
                if cur_uid == prev_uid:
                    entry_attrs.setdefault('managedby', result[0]['dn'])

        # Resolve the owner's dn
        _normalize_owner(self.api.Object.user, entry_attrs)

        # Get the issuer for the URI
        owner = entry_attrs.get('ipatokenowner', None)
        issuer = api.env.realm
        if owner is not None:
            try:
                issuer = ldap.get_entry(owner, ['krbprincipalname'])['krbprincipalname'][0]
            except (NotFound, IndexError):
                pass

        # Build the URI parameters
        args = {}
        args['issuer'] = issuer
        args['secret'] = base64.b32encode(entry_attrs['ipatokenotpkey'])
        args['digits'] = entry_attrs['ipatokenotpdigits']
        args['algorithm'] = entry_attrs['ipatokenotpalgorithm']
        if options['type'] == 'totp':
            args['period'] = entry_attrs['ipatokentotptimestep']
        elif options['type'] == 'hotp':
            args['counter'] = entry_attrs['ipatokenhotpcounter']

        # Build the URI
        label = urllib.quote(entry_attrs['ipatokenuniqueid'])
        parameters = urllib.urlencode(args)
        uri = u'otpauth://%s/%s:%s?%s' % (options['type'], issuer, label, parameters)
        setattr(context, 'uri', uri)

        return dn

    def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
        entry_attrs['uri'] = getattr(context, 'uri')
        _convert_owner(self.api.Object.user, entry_attrs, options)
        return super(otptoken_add, self).post_callback(ldap, dn, entry_attrs, *keys, **options)

    def output_for_cli(self, textui, output, *args, **options):
        uri = output['result'].get('uri', None)
        rv = super(otptoken_add, self).output_for_cli(textui, output, *args, **options)

        # Print QR code to terminal if specified
        if uri and options.get('qrcode', False):
            print "\n"
            qr = qrcode.QRCode()
            qr.add_data(uri)
            qr.make()
            qr.print_tty()
            print "\n"

        return rv


@register()
class otptoken_del(LDAPDelete):
    __doc__ = _('Delete an OTP token.')
    msg_summary = _('Deleted OTP token "%(value)s"')


@register()
class otptoken_mod(LDAPUpdate):
    __doc__ = _('Modify a OTP token.')
    msg_summary = _('Modified OTP token "%(value)s"')

    def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
        notafter_set = True
        notbefore = options.get('ipatokennotbefore', None)
        notafter = options.get('ipatokennotafter', None)
        # notbefore xor notafter, exactly one of them is not None
        if bool(notbefore) ^ bool(notafter):
            result = self.api.Command.otptoken_show(keys[-1])['result']
            if notbefore is None:
                notbefore = result.get('ipatokennotbefore', [None])[0]
            if notafter is None:
                notafter_set = False
                notafter = result.get('ipatokennotafter', [None])[0]

        if not _check_interval(notbefore, notafter):
            if notafter_set:
                raise ValidationError(name='not_after',
                                      error='is before the validity start')
            else:
                raise ValidationError(name='not_before',
                                      error='is after the validity end')
        _normalize_owner(self.api.Object.user, entry_attrs)
        return dn

    def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
        _convert_owner(self.api.Object.user, entry_attrs, options)
        return super(otptoken_mod, self).post_callback(ldap, dn, entry_attrs, *keys, **options)


@register()
class otptoken_find(LDAPSearch):
    __doc__ = _('Search for OTP token.')
    msg_summary = ngettext('%(count)d OTP token matched', '%(count)d OTP tokens matched', 0)

    def pre_callback(self, ldap, filters, *args, **kwargs):
        # This is a hack, but there is no other way to
        # replace the objectClass when searching
        type = kwargs.get('type', '')
        if type not in TOKEN_TYPES:
            type = ''
        filters = filters.replace("(objectclass=ipatoken)",
                                  "(objectclass=ipatoken%s)" % type)

        return super(otptoken_find, self).pre_callback(ldap, filters, *args, **kwargs)

    def args_options_2_entry(self, *args, **options):
        entry = super(otptoken_find, self).args_options_2_entry(*args, **options)
        _normalize_owner(self.api.Object.user, entry)
        return entry

    def post_callback(self, ldap, entries, truncated, *args, **options):
        for entry in entries:
            _convert_owner(self.api.Object.user, entry, options)
        return super(otptoken_find, self).post_callback(ldap, entries, truncated, *args, **options)


@register()
class otptoken_show(LDAPRetrieve):
    __doc__ = _('Display information about an OTP token.')

    def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
        _convert_owner(self.api.Object.user, entry_attrs, options)
        return super(otptoken_show, self).post_callback(ldap, dn, entry_attrs, *keys, **options)

@register()
class otptoken_add_managedby(LDAPAddMember):
    __doc__ = _('Add users that can manage this token.')

    member_attributes = ['managedby']

@register()
class otptoken_remove_managedby(LDAPRemoveMember):
    __doc__ = _('Remove hosts that can manage this host.')

    member_attributes = ['managedby']

class HTTPSConnection(httplib.HTTPConnection):
    "Generates an SSL HTTP connection that performs hostname validation."

    ssl_kwargs = ssl.wrap_socket.func_code.co_varnames[1:ssl.wrap_socket.func_code.co_argcount] #pylint: disable=E1101
    default_port = httplib.HTTPS_PORT

    def __init__(self, host, **kwargs):
        # Strip out arguments we want to pass to ssl.wrap_socket()
        self.__kwargs = {k: v for k, v in kwargs.items() if k in self.ssl_kwargs}
        for k in self.__kwargs:
            del kwargs[k]

        # Can't use super() because the parent is an old-style class.
        httplib.HTTPConnection.__init__(self, host, **kwargs)

    def connect(self):
        # Create the raw socket and wrap it in ssl.
        httplib.HTTPConnection.connect(self)
        self.sock = ssl.wrap_socket(self.sock, **self.__kwargs)

        # Verify the remote hostname.
        match_hostname(self.sock.getpeercert(), self.host.split(':', 1)[0])

class HTTPSHandler(urllib2.HTTPSHandler):
    "Opens SSL HTTPS connections that perform hostname validation."

    def __init__(self, **kwargs):
        self.__kwargs = kwargs

        # Can't use super() because the parent is an old-style class.
        urllib2.HTTPSHandler.__init__(self)

    def __inner(self, host, **kwargs):
        tmp = self.__kwargs.copy()
        tmp.update(kwargs)
        return HTTPSConnection(host, **tmp)

    def https_open(self, req):
        return self.do_open(self.__inner, req)

@register()
class otptoken_sync(Local):
    __doc__ = _('Synchronize an OTP token.')

    header = 'X-IPA-TokenSync-Result'

    takes_options = (
        Str('user', label=_('User ID')),
        Password('password', label=_('Password'), confirm=False),
        Password('first_code', label=_('First Code'), confirm=False),
        Password('second_code', label=_('Second Code'), confirm=False),
    )

    takes_args = (
        Str('token?', label=_('Token ID')),
    )

    def forward(self, *args, **kwargs):
        status = {'result': {self.header: 'unknown'}}

        # Get the sync URI.
        segments = list(urlparse.urlparse(self.api.env.xmlrpc_uri))
        assert segments[0] == 'https' # Ensure encryption.
        segments[2] = segments[2].replace('/xml', '/session/sync_token')
        sync_uri = urlparse.urlunparse(segments)

        # Prepare the query.
        query = {k: v for k, v in kwargs.items()
                    if k in {x.name for x in self.takes_options}}
        if args and args[0] is not None:
            obj = self.api.Object.otptoken
            query['token'] = DN((obj.primary_key.name, args[0]),
                                obj.container_dn, self.api.env.basedn)
        query = urllib.urlencode(query)

        # Sync the token.
        handler = HTTPSHandler(ca_certs=os.path.join(self.api.env.confdir, 'ca.crt'),
                               cert_reqs=ssl.CERT_REQUIRED,
                               ssl_version=ssl.PROTOCOL_TLSv1)
        rsp = urllib2.build_opener(handler).open(sync_uri, query)
        if rsp.getcode() == 200:
            status['result'][self.header] = rsp.info().get(self.header, 'unknown')
        rsp.close()

        return status

    def output_for_cli(self, textui, result, *keys, **options):
        textui.print_plain({
            'ok': 'Token synchronized.',
            'error': 'Error contacting server!',
            'invalid-credentials': 'Invalid Credentials!',
        }.get(result['result'][self.header], 'Unknown Error!'))