# Authors:
#   Jason Gerard DeRose <jderose@redhat.com>
#   Rob Crittenden <rcritten@redhat.com>
#   Pavel Zuna <pzuna@redhat.com>
#
# Copyright (C) 2008  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; version 2 only
#
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""
Services (Identity)
"""
import base64

from OpenSSL import crypto

from ipalib import api, crud, errors
from ipalib import Object
from ipalib import Str, Flag, Bytes
from ipalib import uuid

_container_dn = api.env.container_service
_default_attributes = ['krbprincipalname', 'usercertificate']


def split_principal(principal):
    service = hostname = realm = None

    # Break down the principal into its component parts, which may or
    # may not include the realm.
    sp = principal.split('/')
    if len(sp) != 2:
        raise errors.MalformedServicePrincipal(reason='missing service')

    service = sp[0]
    sr = sp[1].split('@')
    if len(sr) > 2:
        raise errors.MalformedServicePrincipal(
            reason='unable to determine realm'
        )

    hostname = sr[0].lower()
    if len(sr) == 2:
        realm = sr[1].upper()
        # At some point we'll support multiple realms
        if realm != api.env.realm:
            raise errors.RealmMismatch()
    else:
        realm = api.env.realm

    # Note that realm may be None.
    return (service, hostname, realm)

def validate_principal(ugettext, principal):
    (service, hostname, principal) = split_principal(principal)
    return None

def normalize_principal(principal):
    # The principal is already validated when it gets here
    (service, hostname, realm) = split_principal(principal)
    # Put the principal back together again
    principal = '%s/%s@%s' % (service, hostname, realm)
    return unicode(principal)

def validate_certificate(ugettext, cert):
    """
    For now just verify that it is properly base64-encoded.
    """
    try:
        base64.b64decode(cert)
    except Exception, e:
        raise errors.Base64DecodeError(reason=str(e))


class service(Object):
    """
    Service object.
    """
    takes_params = (
        Str('krbprincipalname', validate_principal,
            cli_name='principal',
            doc='Service principal',
            primary_key=True,
            normalizer=lambda value: normalize_principal(value),
        ),
        Bytes('usercertificate?', validate_certificate,
            cli_name='certificate',
            doc='Base-64 encoded server certificate',
        ),
    )

api.register(service)


class service_add(crud.Create):
    """
    Add new service.
    """
    takes_options = (
        Flag('force',
            doc='Force principal name even if not in DNS',
        ),
    )
    def execute(self, principal, **kw):
        """
        Execute the service-add operation.

        The dn should not be passed as a keyword argument as it is constructed
        by this method.

        Returns the entry as it will be created in LDAP.

        :param principal: The service to be added in the form: service/hostname
        :param kw: Keyword arguments for the other LDAP attributes.
        """
        assert 'krbprincipalname' not in kw
        ldap = self.api.Backend.ldap2
        # FIXME: should be in a normalizer. Need to fix normalizers to work
        # on non-unicode data
        if kw.get('usercertificate'):
            kw['usercertificate'] = base64.b64decode(kw['usercertificate'])

        (service, hostname, realm) = split_principal(principal)

        if service.lower() == 'host' and not kw['force']:
            raise errors.HostService()

        # FIXME: once DNS client is done
        # if not kw['force']:
        #     fqdn = hostname + '.'
        #     rs = dnsclient.query(fqdn, dnsclient.DNS_C_IN, dnsclient.DNS_T_A)
        #     if len(rs) == 0:
        #         self.log.debug(
        #             'IPA: DNS A record lookup failed for '%s'" % hostname
        #         )
        #         raise ipaerror.gen_exception(ipaerror.INPUT_NOT_DNS_A_RECORD)
        #     else:
        #         self.log.debug(
        #             'IPA: found %d records for '%s'" % (len(rs), hostname)
        #         )

        entry_attrs = self.args_options_2_entry(principal, **kw)
        entry_attrs['objectclass'] = [
            'krbprincipal', 'krbprincipalaux', 'krbticketpolicyaux',
            'ipaobject', 'ipaservice', 'pkiuser'
        ]
        entry_attrs['ipauniqueid'] = str(uuid.uuid1())
        dn = ldap.make_dn(entry_attrs, 'krbprincipalname', _container_dn)

        ldap.add_entry(dn, entry_attrs)

        return ldap.get_entry(dn, entry_attrs.keys())

    def output_for_cli(self, textui, result, principal, **options):
        (dn, entry_attrs) = result

        textui.print_name(self.name)
        textui.print_attribute('dn', dn)
        textui.print_entry(entry_attrs)
        textui.print_dashed('Created service "%s".' % principal)

api.register(service_add)


class service_del(crud.Delete):
    """
    Delete an existing service.
    """
    def execute(self, principal, **kw):
        """
        Delete a service principal.

        principal is the krbprincipalname of the entry to delete.

        This should be called with much care.

        :param principal: The service to be added in the form: service/hostname
        :param kw: not used
        """
        ldap = self.api.Backend.ldap2

        (dn, entry_attrs) = ldap.find_entry_by_attr(
            'krbprincipalname', principal, 'ipaservice'
        )

        if 'usercerfificate' in entry_attrs:
            cert = entry_attrs['usercertificate']
            x509 = crypto.load_certificate(crypto.FILETYPE_ASN1, cert)
            serial = str(x509.get_serial_number())
            api.Command['cert_revoke'](unicode(serial), revocation_reason=5)

        ldap.delete_entry(dn)

        return True

    def output_for_cli(self, textui, result, principal, **options):
        textui.print_name(self.name)
        textui.print_dashed('Deleted service "%s".' % principal)

api.register(service_del)


class service_mod(crud.Update):
    """
    Modify service.
    """
    def execute(self, principal, **kw):
        ldap = self.api.Backend.ldap
        # FIXME, should be in a normalizer. Need to fix normalizers to work
        # on non-unicode data.
        if kw.get('usercertificate'):
            kw['usercertificate'] = base64.b64decode(kw['usercertificate'])

        dn = ldap.make_dn(entry_attrs, 'krbprincipalname', _container_dn)

        (dn, old_entry_attrs) = ldap.get_entry(dn)
        if 'usercertificate' in old_entry_attrs and 'usercerficate' in kw:
            # FIXME, what to do here? Do we revoke the old cert?
            raise errors.GenericError(format='entry already has a certificate')

        entry_attrs = self.args_options_to_entry(principal, **kw)

        try:
            ldap.update_entry(dn, entry_attrs)
        except errors.EmptyModlist:
            pass

        return ldap.get_entry(dn, entry_attrs.keys())

    def output_to_cli(self, textui, result, principal, **options):
        (dn, entry_attrs) = result

        textui.print_name(self.name)
        textui.print_attribute('dn', dn)
        textui.print_entry(entry_attrs)
        textui.print_dashed('Modified service "%s".' % principal)

api.register(service_mod)


class service_find(crud.Search):
    """
    Search for services.
    """
    takes_options = (
        Flag('all',
            doc='Retrieve all attributes'
        ),
    )

    def execute(self, term, **kw):
        ldap = self.api.Backend.ldap2

        # lisp style!
        custom_filter = '(&(objectclass=ipaService)' \
                          '(!(objectClass=posixAccount))' \
                          '(!(|(krbprincipalname=kadmin/*)' \
                              '(krbprincipalname=K/M@*)' \
                              '(krbprincipalname=krbtgt/*))' \
                          ')' \
                        ')'

        search_kw = self.args_options_2_entry(**kw)
        search_kw['objectclass'] = 'krbprincipal'
        filter = ldap.make_filter(search_kw, rules=ldap.MATCH_ALL)

        search_kw = {}
        for a in _default_attributes:
            search_kw[a] = term
        term_filter = ldap.make_filter(search_kw, exact=False)

        filter = ldap.combine_filters(
            (custom_filter, filter, term_filter), rules=ldap.MATCH_ALL
        )

        if kw['all']:
            attrs_list = ['*']
        else:
            attrs_list = _default_attributes

        try:
            (entries, truncated) = ldap.find_entries(
                filter, attrs_list, _container_dn
            )
        except errors.NotFound:
            (entries, truncated) = (tuple(), False)

        return (entries, truncated)

    def output_for_cli(self, textui, result, principal, **options):
        (entries, truncated) = result

        textui.print_name(self.name)
        for (dn, entry_attrs) in entries:
            textui.print_attribute('dn', dn)
            textui.print_entry(entry_attrs)
            textui.print_plain('')
        textui.print_count(
            len(entries), '%i service matched.', '%i services matched.'
        )
        if truncated:
            textui.print_dashed('These results are truncated.', below=False)
            textui.print_dashed(
                'Please refine your search and try again.', above=False
            )

api.register(service_find)


class service_show(crud.Retrieve):
    """
    Display service.
    """
    takes_options = (
        Flag('all',
            doc='Retrieve all attributes'
        ),
    )

    def execute(self, principal, **kw):
        """
        Execute the service-show operation.

        The dn should not be passed as a keyword argument as it is constructed
        by this method.

        Returns the entry

        :param principal: The service principal to retrieve
        :param kw: Not used.
        """
        ldap = self.api.Backend.ldap2

        dn = ldap.make_dn_from_attr(
            'krbprincipalname', principal, _container_dn
        )

        if kw['all']:
            attrs_list = ['*']
        else:
            attrs_list = _default_attributes

        return ldap.get_entry(dn, attrs_list)

    def output_for_cli(self, textui, result, principal, **options):
        (dn, entry_attrs) = result

        textui.print_name(self.name)
        textui.print_attribute('dn', dn)
        textui.print_entry(entry_attrs)

api.register(service_show)