# 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.


class ServiceStatus(object):
    """Represents the status of the app and in some rare cases the agent.

    Code and description are what is stored in the database. "api_status"
    refers to the status which comes back from the REST API.
    """
    _lookup = {}

    def __init__(self, code, description, api_status):
        self._code = code
        self._description = description
        self._api_status = api_status
        ServiceStatus._lookup[code] = self

    @property
    def action_is_allowed(self):
        allowed_statuses = [
            ServiceStatuses.RUNNING._code,
            ServiceStatuses.SHUTDOWN._code,
            ServiceStatuses.CRASHED._code,
            ServiceStatuses.BLOCKED._code,
        ]
        return self._code in allowed_statuses

    @property
    def api_status(self):
        return self._api_status

    @property
    def code(self):
        return self._code

    @property
    def description(self):
        return self._description

    def __eq__(self, other):
        if not isinstance(other, ServiceStatus):
            return False
        return self.code == other.code

    @staticmethod
    def from_code(code):
        if code not in ServiceStatus._lookup:
            msg = 'Status code %s is not a valid ServiceStatus integer code.'
            raise ValueError(msg % code)
        return ServiceStatus._lookup[code]

    @staticmethod
    def from_description(desc):
        all_items = ServiceStatus._lookup.items()
        status_codes = [code for (code, status) in all_items
                        if status.description == desc]
        if not status_codes:
            msg = 'Status description %s is not a valid ServiceStatus.'
            raise ValueError(msg % desc)
        return ServiceStatus._lookup[status_codes[0]]

    @staticmethod
    def is_valid_code(code):
        return code in ServiceStatus._lookup

    def __str__(self):
        return self._description

    def __repr__(self):
        return self._api_status


class ServiceStatuses(object):
    RUNNING = ServiceStatus(0x01, 'running', 'ACTIVE')
    BLOCKED = ServiceStatus(0x02, 'blocked', 'BLOCKED')
    PAUSED = ServiceStatus(0x03, 'paused', 'SHUTDOWN')
    SHUTDOWN = ServiceStatus(0x04, 'shutdown', 'SHUTDOWN')
    CRASHED = ServiceStatus(0x06, 'crashed', 'SHUTDOWN')
    FAILED = ServiceStatus(0x08, 'failed to spawn', 'FAILED')
    BUILDING = ServiceStatus(0x09, 'building', 'BUILD')
    PROMOTING = ServiceStatus(0x10, 'promoting replica', 'PROMOTE')
    EJECTING = ServiceStatus(0x11, 'ejecting replica source', 'EJECT')
    LOGGING = ServiceStatus(0x12, 'transferring guest logs', 'LOGGING')
    UNKNOWN = ServiceStatus(0x16, 'unknown', 'ERROR')
    NEW = ServiceStatus(0x17, 'new', 'NEW')
    DELETED = ServiceStatus(0x05, 'deleted', 'DELETED')
    FAILED_TIMEOUT_GUESTAGENT = ServiceStatus(0x18, 'guestagent error',
                                              'ERROR')
    INSTANCE_READY = ServiceStatus(0x19, 'instance ready', 'BUILD')
    RESTART_REQUIRED = ServiceStatus(0x20, 'restart required',
                                     'RESTART_REQUIRED')

# Dissuade further additions at run-time.
ServiceStatus.__init__ = None