#    Copyright 2013 Red Hat, Inc
#
#    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 nova import db
from nova import exception
from nova import objects
from nova.objects import base
from nova.objects import fields


OPTIONAL_FIELDS = ['extra_specs', 'projects']


class Flavor(base.NovaPersistentObject, base.NovaObject):
    # Version 1.0: Initial version
    # Version 1.1: Added save_projects(), save_extra_specs(), removed
    #              remoteable from save()
    VERSION = '1.1'

    fields = {
        'id': fields.IntegerField(),
        'name': fields.StringField(nullable=True),
        'memory_mb': fields.IntegerField(),
        'vcpus': fields.IntegerField(),
        'root_gb': fields.IntegerField(),
        'ephemeral_gb': fields.IntegerField(),
        'flavorid': fields.StringField(),
        'swap': fields.IntegerField(),
        'rxtx_factor': fields.FloatField(nullable=True, default=1.0),
        'vcpu_weight': fields.IntegerField(nullable=True),
        'disabled': fields.BooleanField(),
        'is_public': fields.BooleanField(),
        'extra_specs': fields.DictOfStringsField(),
        'projects': fields.ListOfStringsField(),
        }

    def __init__(self, *args, **kwargs):
        super(Flavor, self).__init__(*args, **kwargs)
        self._orig_extra_specs = {}
        self._orig_projects = []

    @staticmethod
    def _from_db_object(context, flavor, db_flavor, expected_attrs=None):
        if expected_attrs is None:
            expected_attrs = []
        for name, field in flavor.fields.items():
            if name in OPTIONAL_FIELDS:
                continue
            value = db_flavor[name]
            if isinstance(field, fields.IntegerField):
                value = value if value is not None else 0
            flavor[name] = value

        if 'extra_specs' in expected_attrs:
            flavor.extra_specs = db_flavor['extra_specs']

        if 'projects' in expected_attrs:
            flavor._load_projects(context)

        flavor._context = context
        flavor.obj_reset_changes()
        return flavor

    @base.remotable
    def _load_projects(self, context):
        self.projects = [x['project_id'] for x in
                         db.flavor_access_get_by_flavor_id(context,
                                                           self.flavorid)]
        self.obj_reset_changes(['projects'])

    def obj_load_attr(self, attrname):
        # NOTE(danms): Only projects could be lazy-loaded right now
        if attrname != 'projects':
            raise exception.ObjectActionError(
                action='obj_load_attr', reason='unable to load %s' % attrname)

        self._load_projects()

    def obj_reset_changes(self, fields=None):
        super(Flavor, self).obj_reset_changes(fields=fields)
        if fields is None or 'extra_specs' in fields:
            self._orig_extra_specs = (dict(self.extra_specs)
                                      if self.obj_attr_is_set('extra_specs')
                                      else {})
        if fields is None or 'projects' in fields:
            self._orig_projects = (list(self.projects)
                                   if self.obj_attr_is_set('projects')
                                   else [])

    def obj_what_changed(self):
        changes = super(Flavor, self).obj_what_changed()
        if ('extra_specs' in self and
            self.extra_specs != self._orig_extra_specs):
            changes.add('extra_specs')
        if 'projects' in self and self.projects != self._orig_projects:
            changes.add('projects')
        return changes

    @classmethod
    def _obj_from_primitive(cls, context, objver, primitive):
        self = super(Flavor, cls)._obj_from_primitive(context, objver,
                                                      primitive)
        changes = self.obj_what_changed()
        if 'extra_specs' not in changes:
            # This call left extra_specs "clean" so update our tracker
            self._orig_extra_specs = (dict(self.extra_specs)
                                      if self.obj_attr_is_set('extra_specs')
                                      else {})
        if 'projects' not in changes:
            # This call left projects "clean" so update our tracker
            self._orig_projects = (list(self.projects)
                                   if self.obj_attr_is_set('projects')
                                   else [])
        return self

    @base.remotable_classmethod
    def get_by_id(cls, context, id):
        db_flavor = db.flavor_get(context, id)
        return cls._from_db_object(context, cls(context), db_flavor,
                                   expected_attrs=['extra_specs'])

    @base.remotable_classmethod
    def get_by_name(cls, context, name):
        db_flavor = db.flavor_get_by_name(context, name)
        return cls._from_db_object(context, cls(context), db_flavor,
                                   expected_attrs=['extra_specs'])

    @base.remotable_classmethod
    def get_by_flavor_id(cls, context, flavor_id, read_deleted=None):
        db_flavor = db.flavor_get_by_flavor_id(context, flavor_id,
                                               read_deleted)
        return cls._from_db_object(context, cls(context), db_flavor,
                                   expected_attrs=['extra_specs'])

    @base.remotable
    def add_access(self, context, project_id):
        if 'projects' in self.obj_what_changed():
            raise exception.ObjectActionError(action='add_access',
                                              reason='projects modified')
        db.flavor_access_add(context, self.flavorid, project_id)
        self._load_projects(context)

    @base.remotable
    def remove_access(self, context, project_id):
        if 'projects' in self.obj_what_changed():
            raise exception.ObjectActionError(action='remove_access',
                                              reason='projects modified')
        db.flavor_access_remove(context, self.flavorid, project_id)
        self._load_projects(context)

    @base.remotable
    def create(self, context):
        if self.obj_attr_is_set('id'):
            raise exception.ObjectActionError(action='create',
                                              reason='already created')
        updates = self.obj_get_changes()
        expected_attrs = []
        for attr in OPTIONAL_FIELDS:
            if attr in updates:
                expected_attrs.append(attr)
        projects = updates.pop('projects', [])
        db_flavor = db.flavor_create(context, updates, projects=projects)
        self._from_db_object(context, self, db_flavor,
                             expected_attrs=expected_attrs)

    @base.remotable
    def save_projects(self, context, to_add=None, to_delete=None):
        """Add or delete projects.

        :param:to_add: A list of projects to add
        :param:to_delete: A list of projects to remove
        """

        to_add = to_add if to_add is not None else []
        to_delete = to_delete if to_delete is not None else []

        for project_id in to_add:
            db.flavor_access_add(context, self.flavorid, project_id)
        for project_id in to_delete:
            db.flavor_access_remove(context, self.flavorid, project_id)
        self.obj_reset_changes(['projects'])

    @base.remotable
    def save_extra_specs(self, context, to_add=None, to_delete=None):
        """Add or delete extra_specs.

        :param:to_add: A dict of new keys to add/update
        :param:to_delete: A list of keys to remove
        """

        to_add = to_add if to_add is not None else []
        to_delete = to_delete if to_delete is not None else []

        if to_add:
            db.flavor_extra_specs_update_or_create(context, self.flavorid,
                                                   to_add)

        for key in to_delete:
            db.flavor_extra_specs_delete(context, self.flavorid, key)
        self.obj_reset_changes(['extra_specs'])

    def save(self):
        context = self._context
        updates = self.obj_get_changes()
        projects = updates.pop('projects', None)
        extra_specs = updates.pop('extra_specs', None)
        if updates:
            raise exception.ObjectActionError(
                action='save', reason='read-only fields were changed')

        if extra_specs is not None:
            deleted_keys = (set(self._orig_extra_specs.keys()) -
                            set(extra_specs.keys()))
            added_keys = self.extra_specs
        else:
            added_keys = deleted_keys = None

        if projects is not None:
            deleted_projects = set(self._orig_projects) - set(projects)
            added_projects = set(projects) - set(self._orig_projects)
        else:
            added_projects = deleted_projects = None

        # NOTE(danms): The first remotable method we call will reset
        # our of the original values for projects and extra_specs. Thus,
        # we collect the added/deleted lists for both above and /then/
        # call these methods to update them.

        if added_keys or deleted_keys:
            self.save_extra_specs(context, self.extra_specs, deleted_keys)

        if added_projects or deleted_projects:
            self.save_projects(context, added_projects, deleted_projects)

    @base.remotable
    def destroy(self, context):
        db.flavor_destroy(context, self.name)


class FlavorList(base.ObjectListBase, base.NovaObject):
    VERSION = '1.1'

    fields = {
        'objects': fields.ListOfObjectsField('Flavor'),
        }
    child_versions = {
        '1.0': '1.0',
        '1.1': '1.1',
        }

    @base.remotable_classmethod
    def get_all(cls, context, inactive=False, filters=None,
                sort_key='flavorid', sort_dir='asc', limit=None, marker=None):
        db_flavors = db.flavor_get_all(context, inactive=inactive,
                                       filters=filters, sort_key=sort_key,
                                       sort_dir=sort_dir, limit=limit,
                                       marker=marker)
        return base.obj_make_list(context, cls(context), objects.Flavor,
                                  db_flavors, expected_attrs=['extra_specs'])
