# Copyright 2011 Grid Dynamics
# 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.

import netaddr
from webob import exc

from nova.api.openstack.api_version_request \
    import MAX_PROXY_API_SUPPORT_VERSION
from nova.api.openstack import common
from nova.api.openstack.compute.schemas import networks as schema
from nova.api.openstack import extensions
from nova.api.openstack import wsgi
from nova.api import validation
from nova import exception
from nova.i18n import _
from nova import network
from nova.objects import base as base_obj
from nova.objects import fields as obj_fields
from nova.policies import networks as net_policies

ALIAS = 'os-networks'


def network_dict(context, network):
    fields = ('id', 'cidr', 'netmask', 'gateway', 'broadcast', 'dns1', 'dns2',
              'cidr_v6', 'gateway_v6', 'label', 'netmask_v6')
    admin_fields = ('created_at', 'updated_at', 'deleted_at', 'deleted',
                    'injected', 'bridge', 'vlan', 'vpn_public_address',
                    'vpn_public_port', 'vpn_private_address', 'dhcp_start',
                    'project_id', 'host', 'bridge_interface', 'multi_host',
                    'priority', 'rxtx_base', 'mtu', 'dhcp_server',
                    'enable_dhcp', 'share_address')
    if network:
        # NOTE(mnaser): We display a limited set of fields so users can know
        #               what networks are available, extra system-only fields
        #               are only visible if they are an admin.
        if context.is_admin:
            fields += admin_fields
        # TODO(mriedem): Remove the NovaObject type check once the
        # network.create API is returning objects.
        is_obj = isinstance(network, base_obj.NovaObject)
        result = {}
        for field in fields:
            # NOTE(mriedem): If network is an object, IPAddress fields need to
            # be cast to a string so they look the same in the response as
            # before the objects conversion.
            if is_obj and isinstance(network.fields[field].AUTO_TYPE,
                                     obj_fields.IPAddress):
                # NOTE(danms): Here, network should be an object, which could
                # have come from neutron and thus be missing most of the
                # attributes. Providing a default to get() avoids trying to
                # lazy-load missing attributes.
                val = network.get(field, None)
                if val is not None:
                    result[field] = str(val)
                else:
                    result[field] = val
            else:
                # It's either not an object or it's not an IPAddress field.
                result[field] = network.get(field, None)
        uuid = network.get('uuid')
        if uuid:
            result['id'] = uuid
        return result
    else:
        return {}


class NetworkController(wsgi.Controller):

    def __init__(self, network_api=None):
        self.network_api = network_api or network.API()

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @extensions.expected_errors(())
    def index(self, req):
        context = req.environ['nova.context']
        context.can(net_policies.POLICY_ROOT % 'view')
        networks = self.network_api.get_all(context)
        result = [network_dict(context, net_ref) for net_ref in networks]
        return {'networks': result}

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @wsgi.response(202)
    @extensions.expected_errors((404, 501))
    @wsgi.action("disassociate")
    def _disassociate_host_and_project(self, req, id, body):
        context = req.environ['nova.context']
        context.can(net_policies.BASE_POLICY_NAME)

        try:
            self.network_api.associate(context, id, host=None, project=None)
        except exception.NetworkNotFound:
            msg = _("Network not found")
            raise exc.HTTPNotFound(explanation=msg)
        except NotImplementedError:
            common.raise_feature_not_supported()

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @extensions.expected_errors(404)
    def show(self, req, id):
        context = req.environ['nova.context']
        context.can(net_policies.POLICY_ROOT % 'view')

        try:
            network = self.network_api.get(context, id)
        except exception.NetworkNotFound:
            msg = _("Network not found")
            raise exc.HTTPNotFound(explanation=msg)
        return {'network': network_dict(context, network)}

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @wsgi.response(202)
    @extensions.expected_errors((404, 409))
    def delete(self, req, id):
        context = req.environ['nova.context']
        context.can(net_policies.BASE_POLICY_NAME)

        try:
            self.network_api.delete(context, id)
        except exception.NetworkInUse as e:
            raise exc.HTTPConflict(explanation=e.format_message())
        except exception.NetworkNotFound:
            msg = _("Network not found")
            raise exc.HTTPNotFound(explanation=msg)

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @extensions.expected_errors((400, 409, 501))
    @validation.schema(schema.create)
    def create(self, req, body):
        context = req.environ['nova.context']
        context.can(net_policies.BASE_POLICY_NAME)

        params = body["network"]

        cidr = params.get("cidr") or params.get("cidr_v6")

        params["num_networks"] = 1
        params["network_size"] = netaddr.IPNetwork(cidr).size

        try:
            network = self.network_api.create(context, **params)[0]
        except (exception.InvalidCidr,
                exception.InvalidIntValue,
                exception.InvalidAddress,
                exception.NetworkNotCreated) as ex:
            raise exc.HTTPBadRequest(explanation=ex.format_message)
        except (exception.CidrConflict,
                exception.DuplicateVlan) as ex:
            raise exc.HTTPConflict(explanation=ex.format_message())
        return {"network": network_dict(context, network)}

    @wsgi.Controller.api_version("2.1", MAX_PROXY_API_SUPPORT_VERSION)
    @wsgi.response(202)
    @extensions.expected_errors((400, 501))
    @validation.schema(schema.add_network_to_project)
    def add(self, req, body):
        context = req.environ['nova.context']
        context.can(net_policies.BASE_POLICY_NAME)

        network_id = body['id']
        project_id = context.project_id

        try:
            self.network_api.add_network_to_project(
                context, project_id, network_id)
        except NotImplementedError:
            common.raise_feature_not_supported()
        except (exception.NoMoreNetworks,
                exception.NetworkNotFoundForUUID) as e:
            raise exc.HTTPBadRequest(explanation=e.format_message())


class Networks(extensions.V21APIExtensionBase):
    """Admin-only Network Management Extension."""

    name = "Networks"
    alias = ALIAS
    version = 1

    def get_resources(self):
        member_actions = {'action': 'POST'}
        collection_actions = {'add': 'POST'}
        res = extensions.ResourceExtension(
            ALIAS, NetworkController(),
            member_actions=member_actions,
            collection_actions=collection_actions)
        return [res]

    def get_controller_extensions(self):
        return []