# Copyright 2011 OpenStack Foundation.
# All Rights Reserved.
#
#    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_config import cfg
from oslo_utils import importutils
import webob

from neutron.api import extensions
from neutron.api.v2 import attributes
from neutron.api.v2 import base
from neutron.api.v2 import resource
from neutron.common import constants as const
from neutron.common import exceptions as n_exc
from neutron import manager
from neutron import quota
from neutron import wsgi


RESOURCE_NAME = 'quota'
RESOURCE_COLLECTION = RESOURCE_NAME + "s"
QUOTAS = quota.QUOTAS
DB_QUOTA_DRIVER = 'neutron.db.quota.driver.DbQuotaDriver'
EXTENDED_ATTRIBUTES_2_0 = {
    RESOURCE_COLLECTION: {}
}


class QuotaSetsController(wsgi.Controller):

    def __init__(self, plugin):
        self._resource_name = RESOURCE_NAME
        self._plugin = plugin
        self._driver = importutils.import_class(
            cfg.CONF.QUOTAS.quota_driver
        )
        self._update_extended_attributes = True

    def _update_attributes(self):
        for quota_resource in QUOTAS.resources.keys():
            attr_dict = EXTENDED_ATTRIBUTES_2_0[RESOURCE_COLLECTION]
            attr_dict[quota_resource] = {
                'allow_post': False,
                'allow_put': True,
                'convert_to': attributes.convert_to_int,
                'validate': {'type:range': [-1, const.DB_INTEGER_MAX_VALUE]},
                'is_visible': True}
        self._update_extended_attributes = False

    def _get_quotas(self, request, tenant_id):
        return self._driver.get_tenant_quotas(
            request.context, QUOTAS.resources, tenant_id)

    def create(self, request, body=None):
        msg = _('POST requests are not supported on this resource.')
        raise webob.exc.HTTPNotImplemented(msg)

    def index(self, request):
        context = request.context
        self._check_admin(context)
        return {self._resource_name + "s":
                self._driver.get_all_quotas(context, QUOTAS.resources)}

    def tenant(self, request):
        """Retrieve the tenant info in context."""
        context = request.context
        if not context.tenant_id:
            raise n_exc.QuotaMissingTenant()
        return {'tenant': {'tenant_id': context.tenant_id}}

    def show(self, request, id):
        if id != request.context.tenant_id:
            self._check_admin(request.context,
                              reason=_("Only admin is authorized "
                                       "to access quotas for another tenant"))
        return {self._resource_name: self._get_quotas(request, id)}

    def _check_admin(self, context,
                     reason=_("Only admin can view or configure quota")):
        if not context.is_admin:
            raise n_exc.AdminRequired(reason=reason)

    def delete(self, request, id):
        self._check_admin(request.context)
        self._driver.delete_tenant_quota(request.context, id)

    def update(self, request, id, body=None):
        self._check_admin(request.context)
        if self._update_extended_attributes:
            self._update_attributes()
        body = base.Controller.prepare_request_body(
            request.context, body, False, self._resource_name,
            EXTENDED_ATTRIBUTES_2_0[RESOURCE_COLLECTION])
        for key, value in body[self._resource_name].items():
            self._driver.update_quota_limit(request.context, id, key, value)
        return {self._resource_name: self._get_quotas(request, id)}


class Quotasv2(extensions.ExtensionDescriptor):
    """Quotas management support."""

    @classmethod
    def get_name(cls):
        return "Quota management support"

    @classmethod
    def get_alias(cls):
        return RESOURCE_COLLECTION

    @classmethod
    def get_description(cls):
        description = 'Expose functions for quotas management'
        if cfg.CONF.QUOTAS.quota_driver == DB_QUOTA_DRIVER:
            description += ' per tenant'
        return description

    @classmethod
    def get_updated(cls):
        return "2012-07-29T10:00:00-00:00"

    @classmethod
    def get_resources(cls):
        """Returns Ext Resources."""
        controller = resource.Resource(
            QuotaSetsController(manager.NeutronManager.get_plugin()),
            faults=base.FAULT_MAP)
        return [extensions.ResourceExtension(
            Quotasv2.get_alias(),
            controller,
            collection_actions={'tenant': 'GET'})]

    def get_extended_resources(self, version):
        if version == "2.0":
            return EXTENDED_ATTRIBUTES_2_0
        else:
            return {}