# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2012 IBM
# 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
import webob.exc

from nova.api.openstack import extensions
from nova.api.openstack import wsgi
from nova.api.openstack import xmlutil
from nova import availability_zones
from nova import db
from nova import exception
from nova.openstack.common import log as logging
from nova.openstack.common import timeutils
from nova import utils

LOG = logging.getLogger(__name__)
authorize = extensions.extension_authorizer('compute', 'services')
CONF = cfg.CONF
CONF.import_opt('service_down_time', 'nova.service')


class ServicesIndexTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('services')
        elem = xmlutil.SubTemplateElement(root, 'service', selector='services')
        elem.set('binary')
        elem.set('host')
        elem.set('zone')
        elem.set('status')
        elem.set('state')
        elem.set('update_at')

        return xmlutil.MasterTemplate(root, 1)


class ServicesUpdateTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('host')
        root.set('host')
        root.set('service')
        root.set('disabled')

        return xmlutil.MasterTemplate(root, 1)


class ServiceController(object):
    @wsgi.serializers(xml=ServicesIndexTemplate)
    def index(self, req):
        """
        Return a list of all running services. Filter by host & service name.
        """
        context = req.environ['nova.context']
        authorize(context)
        now = timeutils.utcnow()
        services = db.service_get_all(context)
        services = availability_zones.set_availability_zones(context, services)

        host = ''
        if 'host' in req.GET:
            host = req.GET['host']
        service = ''
        if 'service' in req.GET:
            service = req.GET['service']
        if host:
            services = [s for s in services if s['host'] == host]
        if service:
            services = [s for s in services if s['binary'] == service]

        svcs = []
        for svc in services:
            delta = now - (svc['updated_at'] or svc['created_at'])
            alive = abs(utils.total_seconds(delta)) <= CONF.service_down_time
            art = (alive and "up") or "down"
            active = 'enabled'
            if svc['disabled']:
                active = 'disabled'
            svcs.append({"binary": svc['binary'], 'host': svc['host'],
                         'zone': svc['availability_zone'],
                         'status': active, 'state': art,
                         'updated_at': svc['updated_at']})
        return {'services': svcs}

    @wsgi.serializers(xml=ServicesUpdateTemplate)
    def update(self, req, id, body):
        """Enable/Disable scheduling for a service."""
        context = req.environ['nova.context']
        authorize(context)

        if id == "enable":
            disabled = False
        elif id == "disable":
            disabled = True
        else:
            raise webob.exc.HTTPNotFound("Unknown action")

        try:
            host = body['host']
            service = body['service']
        except (TypeError, KeyError):
            raise webob.exc.HTTPUnprocessableEntity()

        try:
            svc = db.service_get_by_args(context, host, service)
            if not svc:
                raise webob.exc.HTTPNotFound('Unknown service')

            db.service_update(context, svc['id'], {'disabled': disabled})
        except exception.ServiceNotFound:
            raise webob.exc.HTTPNotFound("service not found")

        return {'host': host, 'service': service, 'disabled': disabled}


class Services(extensions.ExtensionDescriptor):
    """Services support."""

    name = "Services"
    alias = "os-services"
    namespace = "http://docs.openstack.org/compute/ext/services/api/v2"
    updated = "2012-10-28T00:00:00-00:00"

    def get_resources(self):
        resources = []
        resource = extensions.ResourceExtension('os-services',
                                                ServiceController())
        resources.append(resource)
        return resources