# Copyright 2017 The Armada Authors.
#
# 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 re
from uuid import UUID

from oslo_config import cfg
from oslo_log import log as logging

from armada.api import HEALTH_PATH, METRICS_PATH

CONF = cfg.CONF


class AuthMiddleware(object):
    def __init__(self):
        self.logger = logging.getLogger(__name__)

    # Authentication
    def process_request(self, req, resp):
        ctx = req.context

        auth_status = req.get_header('X-SERVICE-IDENTITY-STATUS')
        service = True

        if auth_status is None:
            auth_status = req.get_header('X-IDENTITY-STATUS')
            service = False

        if auth_status == 'Confirmed':
            # Process account and roles
            ctx.authenticated = True
            ctx.user = req.get_header(
                'X-SERVICE-USER-NAME') if service else req.get_header(
                    'X-USER-NAME')
            ctx.user_id = req.get_header(
                'X-SERVICE-USER-ID') if service else req.get_header(
                    'X-USER-ID')
            ctx.user_domain_id = req.get_header(
                'X-SERVICE-USER-DOMAIN-ID') if service else req.get_header(
                    'X-USER-DOMAIN-ID')
            ctx.project_id = req.get_header(
                'X-SERVICE-PROJECT-ID') if service else req.get_header(
                    'X-PROJECT-ID')
            ctx.project_domain_id = req.get_header(
                'X-SERVICE-PROJECT-DOMAIN-ID') if service else req.get_header(
                    'X-PROJECT-DOMAIN-NAME')
            if service:
                ctx.add_roles(req.get_header('X-SERVICE-ROLES').split(','))
            else:
                ctx.add_roles(req.get_header('X-ROLES').split(','))

            if req.get_header('X-IS-ADMIN-PROJECT') == 'True':
                ctx.is_admin_project = True
            else:
                ctx.is_admin_project = False

            self.logger.debug(
                'Request from authenticated user %s with roles %s' %
                (ctx.user, ','.join(ctx.roles)))
        else:
            ctx.authenticated = False


class ContextMiddleware(object):
    def process_request(self, req, resp):
        ctx = req.context

        ext_marker = req.get_header('X-Context-Marker')
        end_user = req.get_header('X-End-User')

        if ext_marker is not None and self.is_valid_uuid(ext_marker):
            ctx.set_external_marker(ext_marker)

        # Set end user from req header in context obj if available
        # else set the user as end user.
        if end_user is not None:
            ctx.set_end_user(end_user)
        else:
            ctx.set_end_user(ctx.user)

    def is_valid_uuid(self, id, version=4):
        try:
            uuid_obj = UUID(id, version=version)
        except (TypeError, ValueError):
            return False

        return str(uuid_obj) == id


class LoggingMiddleware(object):
    def __init__(self):
        self.logger = logging.getLogger(__name__)

    # don't log any headers beginning with X-*
    hdr_exclude = re.compile('x-.*', re.IGNORECASE)

    # don't log anything for health checks
    path_exclude = re.compile('.*/({}|{})$'.format(HEALTH_PATH, METRICS_PATH))

    def exclude_path(self, req):
        return LoggingMiddleware.path_exclude.match(req.path)

    def process_request(self, req, resp):
        """ Set up values to be logged across the request
        """
        if self.exclude_path(req):
            return

        ctx = req.context

        # Get audit logging attributes from context
        user = getattr(ctx, 'user', None)
        req_id = getattr(ctx, 'request_id', None)
        external_ctx = getattr(ctx, 'external_marker', None)
        end_user = getattr(ctx, 'end_user', None)

        # Log request with audit params
        self.logger.info(
            "user=%s request_id=%s ext_ctx=%s end_user=%s Request: %s %s %s",
            user or '-', req_id or '-', external_ctx or '-', end_user or '-',
            req.method, req.uri, req.query_string)

        self._log_headers(req.headers)

    def process_response(self, req, resp, resource, req_succeeded):
        """ Log the response information
        """
        if self.exclude_path(req):
            return

        ctx = req.context

        # Get audit logging attributes from context
        user = getattr(ctx, 'user', None)
        req_id = getattr(ctx, 'request_id', None)
        external_ctx = getattr(ctx, 'external_marker', None)
        end_user = getattr(ctx, 'end_user', None)

        resp.append_header('X-Armada-Req', ctx.request_id)

        # Log response with audit params
        self.logger.info(
            "user=%s request_id=%s ext_ctx=%s end_user=%s Response: %s %s %s",
            user or '-', req_id or '-', external_ctx or '-', end_user or '-',
            req.method, req.uri, resp.status)

        self.logger.debug("Response text:%s", resp.text)

    def _log_headers(self, headers):
        """ Log request headers, while scrubbing sensitive values
        """
        for header, header_value in headers.items():
            if not LoggingMiddleware.hdr_exclude.match(header):
                self.logger.debug("Header %s: %s", header, header_value)
