# Copyright 2017 Catalyst IT Limited
#
#    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 oslo_log import log as logging
from pecan import rest
import wsmeext.pecan as wsme_pecan

from qinling.api.controllers.v1 import resources
from qinling.api.controllers.v1 import types
from qinling.db import api as db_api
from qinling import exceptions as exc
from qinling import rpc
from qinling import status
from qinling.utils import rest_utils

LOG = logging.getLogger(__name__)

POST_REQUIRED = set(['image'])
UPDATE_ALLOWED = set(['name', 'description', 'image'])


class RuntimesController(rest.RestController):
    def __init__(self, *args, **kwargs):
        self.engine_client = rpc.get_engine_client()
        self.type = 'runtime'

        super(RuntimesController, self).__init__(*args, **kwargs)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.Runtime, types.uuid)
    def get(self, id):
        LOG.info("Fetch resource.", resource={'type': self.type, 'id': id})

        runtime_db = db_api.get_runtime(id)

        return resources.Runtime.from_dict(runtime_db.to_dict())

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.Runtimes)
    def get_all(self):
        LOG.info("Get all %ss.", self.type)

        runtimes = [resources.Runtime.from_dict(db_model.to_dict())
                    for db_model in db_api.get_runtimes()]

        return resources.Runtimes(runtimes=runtimes)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(
        resources.Runtime,
        body=resources.Runtime,
        status_code=201
    )
    def post(self, runtime):
        params = runtime.to_dict()

        if not POST_REQUIRED.issubset(set(params.keys())):
            raise exc.InputException(
                'Required param is missing. Required: %s' % POST_REQUIRED
            )

        LOG.info("Creating %s, params: %s", self.type, params)

        params.update({'status': status.CREATING})

        db_model = db_api.create_runtime(params)
        self.engine_client.create_runtime(db_model.id)

        return resources.Runtime.from_dict(db_model.to_dict())

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(None, types.uuid, status_code=204)
    def delete(self, id):
        LOG.info("Delete resource.", resource={'type': self.type, 'id': id})

        with db_api.transaction():
            runtime_db = db_api.get_runtime(id)

            # Runtime can not be deleted if still associate with functions.
            funcs = db_api.get_functions(runtime_id={'eq': id})
            if len(funcs):
                raise exc.NotAllowedException(
                    'Runtime %s is still in use.' % id
                )

            runtime_db.status = status.DELETING

        # Clean related resources asynchronously
        self.engine_client.delete_runtime(id)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(
        resources.Runtime,
        types.uuid,
        body=resources.Runtime
    )
    def put(self, id, runtime):
        """Update runtime.

        Currently, we only support update name, description, image. When
        updating image, send message to engine for asynchronous handling.
        """
        values = {}
        for key in UPDATE_ALLOWED:
            if key in runtime.to_dict():
                values.update({key: runtime.to_dict().get(key)})

        LOG.info('Update resource, params: %s', values,
                 resource={'type': self.type, 'id': id})

        with db_api.transaction():
            if 'image' in values:
                pre_runtime = db_api.get_runtime(id)
                if pre_runtime.status != status.AVAILABLE:
                    raise exc.RuntimeNotAvailableException(
                        'Runtime %s is not available.' % id
                    )

                pre_image = pre_runtime.image
                if pre_image != values['image']:
                    # Ensure there is no function running in the runtime.
                    db_funcs = db_api.get_functions(
                        insecure=True, fields=['id'], runtime_id=id
                    )
                    func_ids = [func.id for func in db_funcs]

                    mappings = db_api.get_function_service_mappings(
                        insecure=True, function_id={'in': func_ids}
                    )
                    if mappings:
                        raise exc.NotAllowedException(
                            'Runtime %s is still in use by functions.' % id
                        )

                    values['status'] = status.UPGRADING

                    self.engine_client.update_runtime(
                        id,
                        image=values['image'],
                        pre_image=pre_image
                    )
                else:
                    values.pop('image')

            runtime_db = db_api.update_runtime(id, values)

        return resources.Runtime.from_dict(runtime_db.to_dict())