# Copyright (c) 2013 Rackspace, Inc.
#
# 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 json
import logging
import os

from keystoneclient import adapter
from keystoneclient.auth.base import BaseAuthPlugin
from keystoneclient import session as ks_session

from barbicanclient import cas
from barbicanclient import containers
from barbicanclient import exceptions
from barbicanclient._i18n import _
from barbicanclient import orders
from barbicanclient import secrets


LOG = logging.getLogger(__name__)
_DEFAULT_SERVICE_TYPE = 'key-manager'
_DEFAULT_SERVICE_INTERFACE = 'public'
_DEFAULT_API_VERSION = 'v1'


class _HTTPClient(adapter.Adapter):

    def __init__(self, session, project_id=None, **kwargs):
        kwargs.setdefault('interface', _DEFAULT_SERVICE_INTERFACE)
        kwargs.setdefault('service_type', _DEFAULT_SERVICE_TYPE)
        kwargs.setdefault('version', _DEFAULT_API_VERSION)
        endpoint = kwargs.pop('endpoint', None)

        super(_HTTPClient, self).__init__(session, **kwargs)

        if endpoint:
            self.endpoint_override = '{0}/{1}'.format(endpoint, self.version)

        if project_id is None:
            self._default_headers = dict()
        else:
            # If provided we'll include the project ID in all requests.
            self._default_headers = {'X-Project-Id': project_id}

    def request(self, *args, **kwargs):
        headers = kwargs.setdefault('headers', {})
        headers.update(self._default_headers)

        # Set raise_exc=False by default so that we handle request exceptions
        kwargs.setdefault('raise_exc', False)

        resp = super(_HTTPClient, self).request(*args, **kwargs)
        self._check_status_code(resp)
        return resp

    def get(self, *args, **kwargs):
        headers = kwargs.setdefault('headers', {})
        headers.setdefault('Accept', 'application/json')

        return super(_HTTPClient, self).get(*args, **kwargs).json()

    def post(self, path, *args, **kwargs):
        if not path[-1] == '/':
            path += '/'

        return super(_HTTPClient, self).post(path, *args, **kwargs).json()

    def _get_raw(self, path, *args, **kwargs):
        return self.request(path, 'GET', *args, **kwargs).content

    def _check_status_code(self, resp):
        status = resp.status_code
        LOG.debug('Response status {0}'.format(status))
        if status == 401:
            LOG.error('Auth error: {0}'.format(self._get_error_message(resp)))
            raise exceptions.HTTPAuthError(
                '{0}'.format(self._get_error_message(resp))
            )
        if not status or status >= 500:
            LOG.error('5xx Server error: {0}'.format(
                self._get_error_message(resp)
            ))
            raise exceptions.HTTPServerError(
                '{0}'.format(self._get_error_message(resp)),
                status
            )
        if status >= 400:
            LOG.error('4xx Client error: {0}'.format(
                self._get_error_message(resp)
            ))
            raise exceptions.HTTPClientError(
                '{0}'.format(self._get_error_message(resp)),
                status
            )

    def _get_error_message(self, resp):
        try:
            response_data = resp.json()
            message = response_data['title']
        except ValueError:
            message = resp.content
        return message


class Client(object):

    def __init__(self, session=None, *args, **kwargs):
        """
        Barbican client object used to interact with barbican service.

        :param session: An instance of keystoneclient.session.Session that
            can be either authenticated, or not authenticated.  When using
            a non-authenticated Session, you must provide some additional
            parameters.  When no session is provided it will default to a
            non-authenticated Session.
        :param endpoint: Barbican endpoint url. Required when a session is not
            given, or when using a non-authenticated session.
            When using an authenticated session, the client will attempt
            to get an endpoint from the session.
        :param project_id: The project ID used for context in Barbican.
            Required when a session is not given, or when using a
            non-authenticated session.
            When using an authenticated session, the project ID will be
            provided by the authentication mechanism.
        :param verify: When a session is not given, the client will create
            a non-authenticated session.  This parameter is passed to the
            session that is created.  If set to False, it allows
            barbicanclient to perform "insecure" TLS (https) requests.
            The server's certificate will not be verified against any
            certificate authorities.
            WARNING: This option should be used with caution.
        :param service_type: Used as an endpoint filter when using an
            authenticated keystone session. Defaults to 'key-management'.
        :param service_name: Used as an endpoint filter when using an
            authenticated keystone session.
        :param interface: Used as an endpoint filter when using an
            authenticated keystone session. Defaults to 'public'.
        :param region_name: Used as an endpoint filter when using an
            authenticated keystone session.
        """
        LOG.debug("Creating Client object")

        if not session:
            session = ks_session.Session(verify=kwargs.pop('verify', True))

        if session.auth is None and kwargs.get('auth') is None:
            if not kwargs.get('endpoint'):
                raise ValueError('Barbican endpoint url must be provided when '
                                 'not using auth in the Keystone Session.')

            if kwargs.get('project_id') is None:
                raise ValueError('Project ID must be provided when not using '
                                 'auth in the Keystone Session')

        httpclient = _HTTPClient(session=session, *args, **kwargs)

        self.secrets = secrets.SecretManager(httpclient)
        self.orders = orders.OrderManager(httpclient)
        self.containers = containers.ContainerManager(httpclient)
        self.cas = cas.CAManager(httpclient)


def env(*vars, **kwargs):
    """Search for the first defined of possibly many env vars

    Returns the first environment variable defined in vars, or
    returns the default defined in kwargs.

    Source: Keystone's shell.py
    """
    for v in vars:
        value = os.environ.get(v, None)
        if value:
            return value
    return kwargs.get('default', '')
