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

# 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 urlparse
import webob

from nova.api.openstack import extensions
from nova.api.openstack import wsgi
from nova.api.openstack import xmlutil
import nova.context
from nova import db
from nova import exception
from nova.openstack.common.gettextutils import _
from nova.openstack.common import log as logging
from nova.openstack.common import strutils
from nova import quota


ALIAS = "os-quota-sets"
QUOTAS = quota.QUOTAS
LOG = logging.getLogger(__name__)
authorize_update = extensions.extension_authorizer('compute',
                                                   'v3:%s:update' % ALIAS)
authorize_show = extensions.extension_authorizer('compute',
                                                 'v3:%s:show' % ALIAS)
authorize_delete = extensions.extension_authorizer('compute',
                                                   'v3:%s:delete' % ALIAS)
authorize_detail = extensions.extension_authorizer('compute',
                                                   'v3:%s:detail' % ALIAS)


class QuotaTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('quota_set', selector='quota_set')
        root.set('id')

        for resource in QUOTAS.resources:
            elem = xmlutil.SubTemplateElement(root, resource)
            elem.text = resource

        return xmlutil.MasterTemplate(root, 1)


class QuotaDetailTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('quota_set', selector='quota_set')
        root.set('id')

        for resource in QUOTAS.resources:
            elem = xmlutil.SubTemplateElement(root, resource,
                                              selector=resource)
            elem.set('in_use')
            elem.set('reserved')
            elem.set('limit')

        return xmlutil.MasterTemplate(root, 1)


class QuotaSetsController(object):

    def _format_quota_set(self, project_id, quota_set):
        """Convert the quota object to a result dict."""
        quota_set.update(id=project_id)
        return dict(quota_set=quota_set)

    def _validate_quota_limit(self, limit, minimum, maximum):
        # NOTE: -1 is a flag value for unlimited
        if limit < -1:
            msg = _("Quota limit must be -1 or greater.")
            raise webob.exc.HTTPBadRequest(explanation=msg)
        if ((limit < minimum) and
           (maximum != -1 or (maximum == -1 and limit != -1))):
            msg = _("Quota limit must greater than %s.") % minimum
            raise webob.exc.HTTPBadRequest(explanation=msg)
        if maximum != -1 and limit > maximum:
            msg = _("Quota limit must less than %s.") % maximum
            raise webob.exc.HTTPBadRequest(explanation=msg)

    def _get_quotas(self, context, id, user_id=None, usages=False):
        if user_id:
            values = QUOTAS.get_user_quotas(context, id, user_id,
                                            usages=usages)
        else:
            values = QUOTAS.get_project_quotas(context, id, usages=usages)

        if usages:
            return values
        else:
            return dict((k, v['limit']) for k, v in values.items())

    @extensions.expected_errors(403)
    @wsgi.serializers(xml=QuotaTemplate)
    def show(self, req, id):
        context = req.environ['nova.context']
        authorize_show(context)
        params = urlparse.parse_qs(req.environ.get('QUERY_STRING', ''))
        user_id = params.get('user_id', [None])[0]
        try:
            nova.context.authorize_project_context(context, id)
            return self._format_quota_set(id,
                    self._get_quotas(context, id, user_id=user_id))
        except exception.NotAuthorized:
            raise webob.exc.HTTPForbidden()

    @extensions.expected_errors(403)
    @wsgi.serializers(xml=QuotaDetailTemplate)
    def detail(self, req, id):
        context = req.environ['nova.context']
        authorize_detail(context)
        user_id = req.GET.get('user_id', None)
        try:
            nova.context.authorize_project_context(context, id)
            return self._format_quota_set(id, self._get_quotas(context, id,
                                                               user_id=user_id,
                                                               usages=True))
        except exception.NotAuthorized:
            raise webob.exc.HTTPForbidden()

    @extensions.expected_errors((400, 403))
    @wsgi.serializers(xml=QuotaTemplate)
    def update(self, req, id, body):
        context = req.environ['nova.context']
        authorize_update(context)
        project_id = id
        params = urlparse.parse_qs(req.environ.get('QUERY_STRING', ''))
        user_id = params.get('user_id', [None])[0]

        bad_keys = []
        force_update = False

        for key, value in body['quota_set'].items():
            if key not in QUOTAS and key != 'force':
                bad_keys.append(key)
                continue
            if key == 'force':
                force_update = strutils.bool_from_string(value)
            elif key != 'force' and value:
                try:
                    value = int(value)
                except (ValueError, TypeError):
                    msg = _("Quota '%(value)s' for %(key)s should be "
                            "integer.") % {'value': value, 'key': key}
                    LOG.warn(msg)
                    raise webob.exc.HTTPBadRequest(explanation=msg)

        if len(bad_keys) > 0:
            msg = _("Bad key(s) %s in quota_set") % ",".join(bad_keys)
            raise webob.exc.HTTPBadRequest(explanation=msg)

        try:
            settable_quotas = QUOTAS.get_settable_quotas(context, project_id,
                                                         user_id=user_id)
        except exception.NotAuthorized:
            raise webob.exc.HTTPForbidden()

        try:
            quotas = self._get_quotas(context, id, user_id=user_id,
                                      usages=True)
        except exception.NotAuthorized:
            raise webob.exc.HTTPForbidden()

        LOG.debug(_("Force update quotas: %s"), force_update)

        for key, value in body['quota_set'].iteritems():
            if key == 'force' or (not value and value != 0):
                continue
            # validate whether already used and reserved exceeds the new
            # quota, this check will be ignored if admin want to force
            # update
            value = int(value)
            if force_update is not True and value >= 0:
                quota_value = quotas.get(key)
                if quota_value and quota_value['limit'] >= 0:
                    quota_used = (quota_value['in_use'] +
                                  quota_value['reserved'])
                    LOG.debug(_("Quota %(key)s used: %(quota_used)s, "
                                "value: %(value)s."),
                              {'key': key, 'quota_used': quota_used,
                               'value': value})
                    if quota_used > value:
                        msg = (_("Quota value %(value)s for %(key)s are "
                                "greater than already used and reserved "
                                "%(quota_used)s") %
                                {'value': value, 'key': key,
                                 'quota_used': quota_used})
                        raise webob.exc.HTTPBadRequest(explanation=msg)

            minimum = settable_quotas[key]['minimum']
            maximum = settable_quotas[key]['maximum']
            self._validate_quota_limit(value, minimum, maximum)
            try:
                db.quota_create(context, project_id, key, value,
                                user_id=user_id)
            except exception.QuotaExists:
                db.quota_update(context, project_id, key, value,
                                user_id=user_id)
            except exception.AdminRequired:
                raise webob.exc.HTTPForbidden()
        return self._format_quota_set(id, self._get_quotas(context, id,
                                                           user_id=user_id))

    @extensions.expected_errors(())
    @wsgi.serializers(xml=QuotaTemplate)
    def defaults(self, req, id):
        context = req.environ['nova.context']
        authorize_show(context)
        return self._format_quota_set(id, QUOTAS.get_defaults(context))

    @extensions.expected_errors(403)
    @wsgi.response(204)
    def delete(self, req, id):
        context = req.environ['nova.context']
        authorize_delete(context)
        params = urlparse.parse_qs(req.environ.get('QUERY_STRING', ''))
        user_id = params.get('user_id', [None])[0]
        try:
            nova.context.authorize_project_context(context, id)
            if user_id:
                QUOTAS.destroy_all_by_project_and_user(context,
                                                       id, user_id)
            else:
                QUOTAS.destroy_all_by_project(context, id)
        except exception.NotAuthorized:
            raise webob.exc.HTTPForbidden()


class QuotaSets(extensions.V3APIExtensionBase):
    """Quotas management support."""

    name = "Quotas"
    alias = ALIAS
    namespace = "http://docs.openstack.org/compute/ext/os-quotas-sets/api/v3"
    version = 1

    def get_resources(self):
        resources = []

        res = extensions.ResourceExtension(ALIAS,
                                            QuotaSetsController(),
                                            member_actions={'defaults': 'GET',
                                                            'detail': 'GET'})
        resources.append(res)

        return resources

    def get_controller_extensions(self):
        return []
