# Copyright 2018 TrilioData Inc.
# All Rights Reserved.

"""
Common Auth Middleware.

"""

from oslo_log import log as logging
from oslo_log import versionutils
from oslo_serialization import jsonutils
import webob.dec
import webob.exc

import dmapi.conf
from dmapi import context
from dmapi.i18n import _
from dmapi import wsgi


CONF = dmapi.conf.CONF
LOG = logging.getLogger(__name__)


def _load_pipeline(loader, pipeline):
    filters = [loader.get_filter(n) for n in pipeline[:-1]]
    app = loader.get_app(pipeline[-1])
    filters.reverse()
    for filter in filters:
        app = filter(app)
    return app


def pipeline_factory_v2(loader, global_conf, **local_conf):
    """A paste pipeline replica that keys off of auth_strategy."""
    return _load_pipeline(loader, local_conf[CONF.api.auth_strategy].split())


class InjectContext(wsgi.Middleware):
    """Add a 'dmapi.context' to WSGI environ."""

    def __init__(self, context, *args, **kwargs):
        self.context = context
        super(InjectContext, self).__init__(*args, **kwargs)

    @webob.dec.wsgify(RequestClass=wsgi.Request)
    def __call__(self, req):
        req.environ['dmapi.context'] = self.context
        return self.application


class DmapiKeystoneContext(wsgi.Middleware):
    """Make a request context from keystone headers."""

    @webob.dec.wsgify(RequestClass=wsgi.Request)
    def __call__(self, req):
        # Build a context, including the auth_token...
        remote_address = req.remote_addr
        if CONF.api.use_forwarded_for:
            remote_address = req.headers.get('X-Forwarded-For', remote_address)

        service_catalog = None
        if req.headers.get('X_SERVICE_CATALOG') is not None:
            try:
                catalog_header = req.headers.get('X_SERVICE_CATALOG')
                service_catalog = jsonutils.loads(catalog_header)
            except ValueError:
                raise webob.exc.HTTPInternalServerError(
                          _('Invalid service catalog json.'))

        # NOTE(jamielennox): This is a full auth plugin set by auth_token
        # middleware in newer versions.
        user_auth_plugin = req.environ.get('keystone.token_auth')

        ctx = context.RequestContext.from_environ(
            req.environ,
            user_auth_plugin=user_auth_plugin,
            remote_address=remote_address,
            service_catalog=service_catalog)

        if ctx.user_id is None:
            LOG.debug("Neither X_USER_ID nor X_USER found in request")
            return webob.exc.HTTPUnauthorized()

        req.environ['dmapi.context'] = ctx
        return self.application