# Copyright 2013 OpenStack Foundation
#
# 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.

"""Extensions supporting OAuth1."""

from __future__ import absolute_import

import abc
import string
import uuid

import oauthlib.common
from oauthlib import oauth1
import six

from keystone.common import dependency
from keystone.common import extension
from keystone.common import manager
from keystone import config
from keystone import exception
from keystone import notifications


RequestValidator = oauth1.RequestValidator
Client = oauth1.Client
AccessTokenEndpoint = oauth1.AccessTokenEndpoint
ResourceEndpoint = oauth1.ResourceEndpoint
AuthorizationEndpoint = oauth1.AuthorizationEndpoint
SIG_HMAC = oauth1.SIGNATURE_HMAC
RequestTokenEndpoint = oauth1.RequestTokenEndpoint
oRequest = oauthlib.common.Request
# The characters used to generate verifiers are limited to alphanumerical
# values for ease of manual entry. Commonly confused characters are omitted.
VERIFIER_CHARS = string.ascii_letters + string.digits
CONFUSED_CHARS = 'jiIl1oO0'
VERIFIER_CHARS = ''.join(c for c in VERIFIER_CHARS if c not in CONFUSED_CHARS)


class Token(object):
    def __init__(self, key, secret):
        self.key = key
        self.secret = secret
        self.verifier = None

    def set_verifier(self, verifier):
        self.verifier = verifier


CONF = config.CONF


def token_generator(*args, **kwargs):
    return uuid.uuid4().hex


EXTENSION_DATA = {
    'name': 'OpenStack OAUTH1 API',
    'namespace': 'http://docs.openstack.org/identity/api/ext/'
                 'OS-OAUTH1/v1.0',
    'alias': 'OS-OAUTH1',
    'updated': '2013-07-07T12:00:0-00:00',
    'description': 'OpenStack OAuth 1.0a Delegated Auth Mechanism.',
    'links': [
        {
            'rel': 'describedby',
            # TODO(dolph): link needs to be revised after
            #              bug 928059 merges
            'type': 'text/html',
            'href': 'https://github.com/openstack/identity-api',
        }
    ]}
extension.register_admin_extension(EXTENSION_DATA['alias'], EXTENSION_DATA)
extension.register_public_extension(EXTENSION_DATA['alias'], EXTENSION_DATA)


def filter_consumer(consumer_ref):
    """Filter out private items in a consumer dict.

    'secret' is never returned.

    :returns: consumer_ref

    """
    if consumer_ref:
        consumer_ref = consumer_ref.copy()
        consumer_ref.pop('secret', None)
    return consumer_ref


def filter_token(access_token_ref):
    """Filter out private items in an access token dict.

    'access_secret' is never returned.

    :returns: access_token_ref

    """
    if access_token_ref:
        access_token_ref = access_token_ref.copy()
        access_token_ref.pop('access_secret', None)
    return access_token_ref


def get_oauth_headers(headers):
    parameters = {}

    # The incoming headers variable is your usual heading from context
    # In an OAuth signed req, where the oauth variables are in the header,
    # they with the key 'Authorization'.

    if headers and 'Authorization' in headers:
        # A typical value for Authorization is seen below
        # 'OAuth realm="", oauth_body_hash="2jm%3D", oauth_nonce="14475435"
        # along with other oauth variables, the 'OAuth ' part is trimmed
        # to split the rest of the headers.

        auth_header = headers['Authorization']
        params = oauth1.rfc5849.utils.parse_authorization_header(auth_header)
        parameters.update(dict(params))
        return parameters


def extract_non_oauth_params(query_string):
    params = oauthlib.common.extract_params(query_string)
    return dict([(k, v) for k, v in params if not k.startswith('oauth_')])


@dependency.provider('oauth_api')
class Manager(manager.Manager):
    """Default pivot point for the OAuth1 backend.

    See :mod:`keystone.common.manager.Manager` for more details on how this
    dynamically calls the backend.

    """
    _ACCESS_TOKEN = "OS-OAUTH1:access_token"
    _REQUEST_TOKEN = "OS-OAUTH1:request_token"
    _CONSUMER = "OS-OAUTH1:consumer"

    def __init__(self):
        super(Manager, self).__init__(CONF.oauth1.driver)

    @notifications.created(_CONSUMER)
    def create_consumer(self, consumer_ref):
        return self.driver.create_consumer(consumer_ref)

    @notifications.updated(_CONSUMER)
    def update_consumer(self, consumer_id, consumer_ref):
        return self.driver.update_consumer(consumer_id, consumer_ref)

    @notifications.deleted(_CONSUMER)
    def delete_consumer(self, consumer_id):
        return self.driver.delete_consumer(consumer_id)

    @notifications.created(_ACCESS_TOKEN)
    def create_access_token(self, request_id, access_token_duration):
        return self.driver.create_access_token(request_id,
                                               access_token_duration)

    @notifications.deleted(_ACCESS_TOKEN, resource_id_arg_index=2)
    def delete_access_token(self, user_id, access_token_id):
        return self.driver.delete_access_token(user_id, access_token_id)

    @notifications.created(_REQUEST_TOKEN, resource_id_arg_index=2)
    def create_request_token(self, consumer_id, requested_project,
                             request_token_duration):
        return self.driver.create_request_token(
            consumer_id, requested_project, request_token_duration)


@six.add_metaclass(abc.ABCMeta)
class Driver(object):
    """Interface description for an OAuth1 driver."""

    @abc.abstractmethod
    def create_consumer(self, consumer_ref):
        """Create consumer.

        :param consumer_ref: consumer ref with consumer name
        :type consumer_ref: dict
        :returns: consumer_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def update_consumer(self, consumer_id, consumer_ref):
        """Update consumer.

        :param consumer_id: id of consumer to update
        :type consumer_id: string
        :param consumer_ref: new consumer ref with consumer name
        :type consumer_ref: dict
        :returns: consumer_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def list_consumers(self):
        """List consumers.

        :returns: list of consumers

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def get_consumer(self, consumer_id):
        """Get consumer, returns the consumer id (key)
        and description.

        :param consumer_id: id of consumer to get
        :type consumer_id: string
        :returns: consumer_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def get_consumer_with_secret(self, consumer_id):
        """Like get_consumer() but returned consumer_ref includes
        the consumer secret.

        Secrets should only be shared upon consumer creation; the
        consumer secret is required to verify incoming OAuth requests.

        :param consumer_id: id of consumer to get
        :type consumer_id: string
        :returns: consumer_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def delete_consumer(self, consumer_id):
        """Delete consumer.

        :param consumer_id: id of consumer to get
        :type consumer_id: string
        :returns: None.

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def list_access_tokens(self, user_id):
        """List access tokens.

        :param user_id: search for access tokens authorized by given user id
        :type user_id: string
        :returns: list of access tokens the user has authorized

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def delete_access_token(self, user_id, access_token_id):
        """Delete access token.

        :param user_id: authorizing user id
        :type user_id: string
        :param access_token_id: access token to delete
        :type access_token_id: string
        :returns: None

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def create_request_token(self, consumer_id, requested_project,
                             request_token_duration):
        """Create request token.

        :param consumer_id: the id of the consumer
        :type consumer_id: string
        :param requested_project_id: requested project id
        :type requested_project_id: string
        :param request_token_duration: duration of request token
        :type request_token_duration: string
        :returns: request_token_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def get_request_token(self, request_token_id):
        """Get request token.

        :param request_token_id: the id of the request token
        :type request_token_id: string
        :returns: request_token_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def get_access_token(self, access_token_id):
        """Get access token.

        :param access_token_id: the id of the access token
        :type access_token_id: string
        :returns: access_token_ref

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def authorize_request_token(self, request_id, user_id, role_ids):
        """Authorize request token.

        :param request_id: the id of the request token, to be authorized
        :type request_id: string
        :param user_id: the id of the authorizing user
        :type user_id: string
        :param role_ids: list of role ids to authorize
        :type role_ids: list
        :returns: verifier

        """
        raise exception.NotImplemented()  # pragma: no cover

    @abc.abstractmethod
    def create_access_token(self, request_id, access_token_duration):
        """Create access token.

        :param request_id: the id of the request token, to be deleted
        :type request_id: string
        :param access_token_duration: duration of an access token
        :type access_token_duration: string
        :returns: access_token_ref

        """
        raise exception.NotImplemented()  # pragma: no cover
