# Copyright 2012 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.

from oslo_log import log
from oslo_serialization import jsonutils

from keystone.common import authorization
from keystone.common import wsgi
from keystone import exception


LOG = log.getLogger(__name__)


class TokenAuthMiddleware(wsgi.Middleware):
    def process_request(self, request):
        context = request.environ.setdefault(wsgi.CONTEXT_ENV, {})

        token = request.headers.get(authorization.AUTH_TOKEN_HEADER)
        context['token_id'] = token

        subject_token = request.headers.get(authorization.SUBJECT_TOKEN_HEADER)
        if subject_token:
            context['subject_token_id'] = subject_token


class JsonBodyMiddleware(wsgi.Middleware):
    """Middleware to allow method arguments to be passed as serialized JSON.

    Accepting arguments as JSON is useful for accepting data that may be more
    complex than simple primitives.

    Filters out the parameters `self`, `context` and anything beginning with
    an underscore.

    """

    def process_request(self, request):
        # Abort early if we don't have any work to do
        params_json = request.body
        if not params_json:
            return

        # Reject unrecognized content types. Empty string indicates
        # the client did not explicitly set the header
        if request.content_type not in ('application/json', ''):
            e = exception.ValidationError(attribute='application/json',
                                          target='Content-Type header')
            return wsgi.render_exception(e, request=request)

        params_parsed = {}
        try:
            params_parsed = jsonutils.loads(params_json)
        except ValueError:
            e = exception.ValidationError(attribute='valid JSON',
                                          target='request body')
            return wsgi.render_exception(e, request=request)
        finally:
            if not params_parsed:
                params_parsed = {}

        if not isinstance(params_parsed, dict):
            e = exception.ValidationError(attribute='valid JSON object',
                                          target='request body')
            return wsgi.render_exception(e, request=request)

        params = {}
        for k, v in params_parsed.items():
            if k in ('self', 'context'):
                continue
            if k.startswith('_'):
                continue
            params[k] = v

        request.environ[wsgi.PARAMS_ENV] = params


class NormalizingFilter(wsgi.Middleware):
    """Middleware filter to handle URL normalization."""

    def process_request(self, request):
        """Normalize URLs."""
        # Removes a trailing slash from the given path, if any.
        if (len(request.environ['PATH_INFO']) > 1 and
                request.environ['PATH_INFO'][-1] == '/'):
            request.environ['PATH_INFO'] = request.environ['PATH_INFO'][:-1]
        # Rewrites path to root if no path is given.
        elif not request.environ['PATH_INFO']:
            request.environ['PATH_INFO'] = '/'
