# 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:`~openstack.profile.Profile` is the class that is used to
define the various preferences for different services.  The preferences that
are currently supported are service name, region, version and interface.
The :class:`~openstack.profile.Profile` and the
:class:`~openstack.connection.Connection` classes are the most important
user facing classes.

Examples
--------

The :class:`~openstack.profile.Profile` class is constructed
with no arguments.

Set Methods
~~~~~~~~~~~

A user's preferences are set based on the service type.  Service type would
normally be something like 'compute', 'identity', 'object-store', etc.::

    from openstack import profile
    prof = profile.Profile()
    prof.set_name('compute', 'matrix')
    prof.set_region(prof.ALL, 'zion')
    prof.set_version('identity', 'v3')
    prof.set_interface('object-store', 'internal')
    for service in prof.get_services():
        print str(prof.get_preference(service.service_type))

The resulting preference print out would look something like::

    service_type=compute,region=zion,service_name=matrix
    service_type=network,region=zion
    service_type=database,region=zion
    service_type=image,region=zion
    service_type=metering,region=zion
    service_type=orchestration,region=zion
    service_type=object-store,interface=internal,region=zion
    service_type=identity,region=zion,version=v3
"""

import logging
import six

from openstack.block_store import block_store_service
from openstack.cluster import cluster_service
from openstack.compute import compute_service
from openstack.database import database_service
from openstack import exceptions
from openstack.identity import identity_service
from openstack.image import image_service
from openstack.key_management import key_management_service
from openstack.message import message_service
from openstack.metric import metric_service
from openstack import module_loader
from openstack.network import network_service
from openstack.object_store import object_store_service
from openstack.orchestration import orchestration_service
from openstack.telemetry import telemetry_service

_logger = logging.getLogger(__name__)


class Profile(object):

    ALL = "*"
    """Wildcard service identifier representing all services."""

    def __init__(self, extensions=None):
        """User preference for each service.

        :param list extensions: List of entry point namespace to load.

        Create a new :class:`~openstack.profile.Profile`
        object with no preferences defined, but knowledge of the services.
        Services are identified by their service type, e.g.: 'identity',
        'compute', etc.
        """
        self._preferences = {}
        self._services = {}
        self._add_service(cluster_service.ClusterService())
        self._add_service(compute_service.ComputeService())
        self._add_service(database_service.DatabaseService())
        self._add_service(identity_service.IdentityService())
        self._add_service(image_service.ImageService())
        self._add_service(metric_service.MetricService())
        self._add_service(network_service.NetworkService())
        self._add_service(object_store_service.ObjectStoreService())
        self._add_service(orchestration_service.OrchestrationService())
        self._add_service(key_management_service.KeyManagementService())
        self._add_service(telemetry_service.TelemetryService())
        self._add_service(block_store_service.BlockStoreService())
        self._add_service(message_service.MessageService())

        if extensions:
            for extension in extensions:
                self._load_extension(extension)
        self.service_names = sorted(self._services.keys())

    def __repr__(self):
        return repr(self._preferences)

    def _add_service(self, serv):
        serv.set_interface(None)
        self._services[serv.service_type] = serv

    def _load_extension(self, namespace):
        """Load a service extension.

        :param str namespace: Entry point namespace
        """
        services = module_loader.load_service_extensions(namespace)
        for service_type in services:
            if service_type in self._services:
                _logger.debug("Overriding %s with %s", service_type,
                              services[service_type])
            self._add_service(services[service_type])

    def get_preference(self, service):
        """Get a service preference.

        :param str service: Desired service type.
        """
        return self._preferences.get(service, None)

    def get_services(self):
        """Get a list of all the known services."""
        services = []
        for name, service in six.iteritems(self._services):
            services.append(service)
        return services

    def _get_service(self, service):
        """Get a valid service filter."""
        serv = self._services.get(service, None)
        if serv is not None:
            self._preferences[service] = serv
            return serv
        msg = ("Service %s not in list of valid services: %s" %
               (service, self.service_names))
        raise exceptions.SDKException(msg)

    def set_name(self, service, name):
        """Set the desired name for the specified service.

        :param str service: Service type.
        :param str name: Desired service name.
        """
        if service == self.ALL:
            services = self.service_names
        else:
            services = [service]
        for service in services:
            self._get_service(service).service_name = name

    def set_region(self, service, region):
        """Set the desired region for the specified service.

        :param str service: Service type.
        :param str region: Desired service region.
        """
        if service == self.ALL:
            services = self.service_names
        else:
            services = [service]
        for service in services:
            self._get_service(service).region = region

    def set_version(self, service, version):
        """Set the desired version for the specified service.

        :param str service: Service type.
        :param str version: Desired service version.
        """
        self._get_service(service).version = version

    def set_interface(self, service, interface):
        """Set the desired interface for the specified service.

        :param str service: Service type.
        :param str interface: Desired service interface.
        """
        if service == self.ALL:
            services = self.service_names
        else:
            services = [service]
        for service in services:
            self._get_service(service).set_interface(interface)