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

#
#    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 heat.db import api as db_api
from heat.common import exception
from heat.common import identifier
from heat.openstack.common import log as logging

logger = logging.getLogger(__name__)


class Event(object):
    '''Class representing a Resource state change.'''

    def __init__(self, context, stack, resource,
                 new_state, reason,
                 physical_resource_id, resource_properties,
                 timestamp=None, id=None):
        '''
        Initialise from a context, stack, resource, event information and
        current resource data. The timestamp and database ID may also be
        initialised if the event is already in the database.
        '''
        self.context = context
        self.resource = resource
        self.stack = stack
        self.new_state = new_state
        self.reason = reason
        self.physical_resource_id = physical_resource_id
        self.resource_properties = dict(resource_properties)
        self.timestamp = timestamp
        self.id = id

    @classmethod
    def load(cls, context, event_id):
        '''Retrieve an Event from the database'''
        from heat.engine import parser

        ev = db_api.event_get(context, event_id)
        if ev is None:
            message = 'No event exists with id "%s"' % str(event_id)
            raise exception.NotFound(message)

        stack = parser.Stack.load(context, ev.stack_id)
        resource = stack[ev.logical_resource_id]

        event = cls(context, stack, resource,
                    ev.name, ev.resource_status_reason,
                    ev.physical_resource_id, ev.resource_properties,
                    ev.created_at, ev.id)

        return event

    def store(self):
        '''Store the Event in the database'''
        ev = {
            'logical_resource_id': self.resource.name,
            'physical_resource_id': self.physical_resource_id,
            'stack_id': self.stack.id,
            'stack_name': self.stack.name,
            'resource_status': self.new_state,
            'name': self.new_state,
            'resource_status_reason': self.reason,
            'resource_type': self.resource.type(),
            'resource_properties': self.resource_properties,
        }

        if self.timestamp is not None:
            ev['created_at'] = self.timestamp

        if self.id is not None:
            logger.warning('Duplicating event')

        new_ev = db_api.event_create(self.context, ev)
        self.id = new_ev.id
        return self.id

    def identifier(self):
        '''Return a unique identifier for the event'''
        if self.id is None:
            return None

        return identifier.EventIdentifier(event_id=str(self.id),
                                          **self.resource.identifier())
