# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import abc
import logging

from oslo.config import cfg
import six
import six.moves.urllib.parse as urlparse

from keystoneclient.auth.identity import base
from keystoneclient import discover
from keystoneclient import exceptions
from keystoneclient.i18n import _, _LW


LOG = logging.getLogger(__name__)


def get_options():
    return [
        cfg.StrOpt('domain-id', help='Domain ID to scope to'),
        cfg.StrOpt('domain-name', help='Domain name to scope to'),
        cfg.StrOpt('tenant-id', help='Tenant ID to scope to'),
        cfg.StrOpt('tenant-name', help='Tenant name to scope to'),
        cfg.StrOpt('project-id', help='Project ID to scope to'),
        cfg.StrOpt('project-name', help='Project name to scope to'),
        cfg.StrOpt('project-domain-id',
                   help='Domain ID containing project'),
        cfg.StrOpt('project-domain-name',
                   help='Domain name containing project'),
        cfg.StrOpt('trust-id', help='Trust ID'),
    ]


@six.add_metaclass(abc.ABCMeta)
class BaseGenericPlugin(base.BaseIdentityPlugin):
    """An identity plugin that is not version dependant.

    Internally we will construct a version dependant plugin with the resolved
    URL and then proxy all calls from the base plugin to the versioned one.
    """

    def __init__(self, auth_url,
                 tenant_id=None,
                 tenant_name=None,
                 project_id=None,
                 project_name=None,
                 project_domain_id=None,
                 project_domain_name=None,
                 domain_id=None,
                 domain_name=None,
                 trust_id=None):
        super(BaseGenericPlugin, self).__init__(auth_url=auth_url)

        self._project_id = project_id or tenant_id
        self._project_name = project_name or tenant_name
        self._project_domain_id = project_domain_id
        self._project_domain_name = project_domain_name
        self._domain_id = domain_id
        self._domain_name = domain_name
        self._trust_id = trust_id

        self._plugin = None

    @abc.abstractmethod
    def create_plugin(self, session, version, url, raw_status=None):
        """Create a plugin from the given paramters.

        This function will be called multiple times with the version and url
        of a potential endpoint. If a plugin can be constructed that fits the
        params then it should return it. If not return None and then another
        call will be made with other available URLs.

        :param Session session: A session object.
        :param tuple version: A tuple of the API version at the URL.
        :param string url: The base URL for this version.
        :param string raw_status: The status that was in the discovery field.

        :returns: A plugin that can match the parameters or None if nothing.
        """
        return None

    @property
    def _has_domain_scope(self):
        """Are there domain parameters.

        Domain parameters are v3 only so returns if any are set.

        :returns: True if a domain parameter is set, false otherwise.
        """
        return any([self._domain_id, self._domain_name,
                    self._project_domain_id, self._project_domain_name])

    @property
    def _v2_params(self):
        """Parameters that are common to v2 plugins."""
        return {'trust_id': self._trust_id,
                'tenant_id': self._project_id,
                'tenant_name': self._project_name}

    @property
    def _v3_params(self):
        """Parameters that are common to v3 plugins."""
        return {'trust_id': self._trust_id,
                'project_id': self._project_id,
                'project_name': self._project_name,
                'project_domain_id': self._project_domain_id,
                'project_domain_name': self._project_domain_name,
                'domain_id': self._domain_id,
                'domain_name': self._domain_name}

    def _do_create_plugin(self, session):
        plugin = None

        try:
            disc = self.get_discovery(session,
                                      self.auth_url,
                                      authenticated=False)
        except (exceptions.DiscoveryFailure,
                exceptions.HTTPError,
                exceptions.ConnectionError):
            LOG.warn(_LW('Discovering versions from the identity service '
                         'failed when creating the password plugin. '
                         'Attempting to determine version from URL.'))

            url_parts = urlparse.urlparse(self.auth_url)
            path = url_parts.path.lower()

            if path.startswith('/v2.0') and not self._has_domain_scope:
                plugin = self.create_plugin(session, (2, 0), self.auth_url)
            elif path.startswith('/v3'):
                plugin = self.create_plugin(session, (3, 0), self.auth_url)

        else:
            disc_data = disc.version_data()

            for data in disc_data:
                version = data['version']

                if (discover.version_match((2,), version) and
                        self._has_domain_scope):
                    # NOTE(jamielennox): if there are domain parameters there
                    # is no point even trying against v2 APIs.
                    continue

                plugin = self.create_plugin(session,
                                            version,
                                            data['url'],
                                            raw_status=data['raw_status'])

                if plugin:
                    break

        if plugin:
            return plugin

        # so there were no URLs that i could use for auth of any version.
        msg = _('Could not determine a suitable URL for the plugin')
        raise exceptions.DiscoveryFailure(msg)

    def get_auth_ref(self, session, **kwargs):
        if not self._plugin:
            self._plugin = self._do_create_plugin(session)

        return self._plugin.get_auth_ref(session, **kwargs)

    @classmethod
    def get_options(cls):
        options = super(BaseGenericPlugin, cls).get_options()
        options.extend(get_options())
        return options