# Copyright 2020 Canonical Ltd.
#
# 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.

import asyncio
import logging

import time

import juju.errors
from juju.model import Model
from juju.machine import Machine
from juju.application import Application
from juju.unit import Unit
from juju.client._definitions import (
    FullStatus,
    QueryApplicationOffersResults,
    Cloud,
    CloudCredential,
)
from juju.controller import Controller
from juju.client import client
from juju import tag

from n2vc.config import ModelConfig
from n2vc.juju_watcher import JujuModelWatcher
from n2vc.provisioner import AsyncSSHProvisioner
from n2vc.n2vc_conn import N2VCConnector
from n2vc.exceptions import (
    JujuMachineNotFound,
    JujuApplicationNotFound,
    JujuLeaderUnitNotFound,
    JujuActionNotFound,
    JujuControllerFailedConnecting,
    JujuApplicationExists,
    JujuInvalidK8sConfiguration,
)
from n2vc.utils import DB_DATA
from osm_common.dbbase import DbException
from kubernetes.client.configuration import Configuration

RBAC_LABEL_KEY_NAME = "rbac-id"


class Libjuju:
    def __init__(
        self,
        endpoint: str,
        api_proxy: str,
        username: str,
        password: str,
        cacert: str,
        loop: asyncio.AbstractEventLoop = None,
        log: logging.Logger = None,
        db: dict = None,
        n2vc: N2VCConnector = None,
        model_config: ModelConfig = {},
    ):
        """
        Constructor

        :param: endpoint:               Endpoint of the juju controller (host:port)
        :param: api_proxy:              Endpoint of the juju controller - Reachable from the VNFs
        :param: username:               Juju username
        :param: password:               Juju password
        :param: cacert:                 Juju CA Certificate
        :param: loop:                   Asyncio loop
        :param: log:                    Logger
        :param: db:                     DB object
        :param: n2vc:                   N2VC object
        :param: apt_mirror:             APT Mirror
        :param: enable_os_upgrade:      Enable OS Upgrade
        """

        self.log = log or logging.getLogger("Libjuju")
        self.db = db
        db_endpoints = self._get_api_endpoints_db()
        self.endpoints = None
        if (db_endpoints and endpoint not in db_endpoints) or not db_endpoints:
            self.endpoints = [endpoint]
            self._update_api_endpoints_db(self.endpoints)
        else:
            self.endpoints = db_endpoints
        self.api_proxy = api_proxy
        self.username = username
        self.password = password
        self.cacert = cacert
        self.loop = loop or asyncio.get_event_loop()
        self.n2vc = n2vc

        # Generate config for models
        self.model_config = model_config

        self.loop.set_exception_handler(self.handle_exception)
        self.creating_model = asyncio.Lock(loop=self.loop)

        self.log.debug("Libjuju initialized!")

        self.health_check_task = self._create_health_check_task()

    def _create_health_check_task(self):
        return self.loop.create_task(self.health_check())

    async def get_controller(self, timeout: float = 15.0) -> Controller:
        """
        Get controller

        :param: timeout: Time in seconds to wait for controller to connect
        """
        controller = None
        try:
            controller = Controller(loop=self.loop)
            await asyncio.wait_for(
                controller.connect(
                    endpoint=self.endpoints,
                    username=self.username,
                    password=self.password,
                    cacert=self.cacert,
                ),
                timeout=timeout,
            )
            endpoints = await controller.api_endpoints
            if self.endpoints != endpoints:
                self.endpoints = endpoints
                self._update_api_endpoints_db(self.endpoints)
            return controller
        except asyncio.CancelledError as e:
            raise e
        except Exception as e:
            self.log.error(
                "Failed connecting to controller: {}...".format(self.endpoints)
            )
            if controller:
                await self.disconnect_controller(controller)
            raise JujuControllerFailedConnecting(e)

    async def disconnect(self):
        """Disconnect"""
        # Cancel health check task
        self.health_check_task.cancel()
        self.log.debug("Libjuju disconnected!")

    async def disconnect_model(self, model: Model):
        """
        Disconnect model

        :param: model: Model that will be disconnected
        """
        await model.disconnect()

    async def disconnect_controller(self, controller: Controller):
        """
        Disconnect controller

        :param: controller: Controller that will be disconnected
        """
        if controller:
            await controller.disconnect()

    async def add_model(self, model_name: str, cloud_name: str, credential_name=None):
        """
        Create model

        :param: model_name: Model name
        :param: cloud_name: Cloud name
        :param: credential_name: Credential name to use for adding the model
                                 If not specified, same name as the cloud will be used.
        """

        # Get controller
        controller = await self.get_controller()
        model = None
        try:
            # Block until other workers have finished model creation
            while self.creating_model.locked():
                await asyncio.sleep(0.1)

            # Create the model
            async with self.creating_model:
                if await self.model_exists(model_name, controller=controller):
                    return
                self.log.debug("Creating model {}".format(model_name))
                model = await controller.add_model(
                    model_name,
                    config=self.model_config,
                    cloud_name=cloud_name,
                    credential_name=credential_name or cloud_name,
                )
        finally:
            if model:
                await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def get_model(
        self, controller: Controller, model_name: str, id=None
    ) -> Model:
        """
        Get model from controller

        :param: controller: Controller
        :param: model_name: Model name

        :return: Model: The created Juju model object
        """
        return await controller.get_model(model_name)

    async def model_exists(
        self, model_name: str, controller: Controller = None
    ) -> bool:
        """
        Check if model exists

        :param: controller: Controller
        :param: model_name: Model name

        :return bool
        """
        need_to_disconnect = False

        # Get controller if not passed
        if not controller:
            controller = await self.get_controller()
            need_to_disconnect = True

        # Check if model exists
        try:
            return model_name in await controller.list_models()
        finally:
            if need_to_disconnect:
                await self.disconnect_controller(controller)

    async def models_exist(self, model_names: [str]) -> (bool, list):
        """
        Check if models exists

        :param: model_names: List of strings with model names

        :return (bool, list[str]): (True if all models exists, List of model names that don't exist)
        """
        if not model_names:
            raise Exception(
                "model_names must be a non-empty array. Given value: {}".format(
                    model_names
                )
            )
        non_existing_models = []
        models = await self.list_models()
        existing_models = list(set(models).intersection(model_names))
        non_existing_models = list(set(model_names) - set(existing_models))

        return (
            len(non_existing_models) == 0,
            non_existing_models,
        )

    async def get_model_status(self, model_name: str) -> FullStatus:
        """
        Get model status

        :param: model_name: Model name

        :return: Full status object
        """
        controller = await self.get_controller()
        model = await self.get_model(controller, model_name)
        try:
            return await model.get_status()
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def create_machine(
        self,
        model_name: str,
        machine_id: str = None,
        db_dict: dict = None,
        progress_timeout: float = None,
        total_timeout: float = None,
        series: str = "bionic",
        wait: bool = True,
    ) -> (Machine, bool):
        """
        Create machine

        :param: model_name:         Model name
        :param: machine_id:         Machine id
        :param: db_dict:            Dictionary with data of the DB to write the updates
        :param: progress_timeout:   Maximum time between two updates in the model
        :param: total_timeout:      Timeout for the entity to be active
        :param: series:             Series of the machine (xenial, bionic, focal, ...)
        :param: wait:               Wait until machine is ready

        :return: (juju.machine.Machine, bool):  Machine object and a boolean saying
                                                if the machine is new or it already existed
        """
        new = False
        machine = None

        self.log.debug(
            "Creating machine (id={}) in model: {}".format(machine_id, model_name)
        )

        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)
        try:
            if machine_id is not None:
                self.log.debug(
                    "Searching machine (id={}) in model {}".format(
                        machine_id, model_name
                    )
                )

                # Get machines from model and get the machine with machine_id if exists
                machines = await model.get_machines()
                if machine_id in machines:
                    self.log.debug(
                        "Machine (id={}) found in model {}".format(
                            machine_id, model_name
                        )
                    )
                    machine = machines[machine_id]
                else:
                    raise JujuMachineNotFound("Machine {} not found".format(machine_id))

            if machine is None:
                self.log.debug("Creating a new machine in model {}".format(model_name))

                # Create machine
                machine = await model.add_machine(
                    spec=None, constraints=None, disks=None, series=series
                )
                new = True

                # Wait until the machine is ready
                self.log.debug(
                    "Wait until machine {} is ready in model {}".format(
                        machine.entity_id, model_name
                    )
                )
                if wait:
                    await JujuModelWatcher.wait_for(
                        model=model,
                        entity=machine,
                        progress_timeout=progress_timeout,
                        total_timeout=total_timeout,
                        db_dict=db_dict,
                        n2vc=self.n2vc,
                    )
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

        self.log.debug(
            "Machine {} ready at {} in model {}".format(
                machine.entity_id, machine.dns_name, model_name
            )
        )
        return machine, new

    async def provision_machine(
        self,
        model_name: str,
        hostname: str,
        username: str,
        private_key_path: str,
        db_dict: dict = None,
        progress_timeout: float = None,
        total_timeout: float = None,
    ) -> str:
        """
        Manually provisioning of a machine

        :param: model_name:         Model name
        :param: hostname:           IP to access the machine
        :param: username:           Username to login to the machine
        :param: private_key_path:   Local path for the private key
        :param: db_dict:            Dictionary with data of the DB to write the updates
        :param: progress_timeout:   Maximum time between two updates in the model
        :param: total_timeout:      Timeout for the entity to be active

        :return: (Entity): Machine id
        """
        self.log.debug(
            "Provisioning machine. model: {}, hostname: {}, username: {}".format(
                model_name, hostname, username
            )
        )

        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)

        try:
            # Get provisioner
            provisioner = AsyncSSHProvisioner(
                host=hostname,
                user=username,
                private_key_path=private_key_path,
                log=self.log,
            )

            # Provision machine
            params = await provisioner.provision_machine()

            params.jobs = ["JobHostUnits"]

            self.log.debug("Adding machine to model")
            connection = model.connection()
            client_facade = client.ClientFacade.from_connection(connection)

            results = await client_facade.AddMachines(params=[params])
            error = results.machines[0].error

            if error:
                msg = "Error adding machine: {}".format(error.message)
                self.log.error(msg=msg)
                raise ValueError(msg)

            machine_id = results.machines[0].machine

            self.log.debug("Installing Juju agent into machine {}".format(machine_id))
            asyncio.ensure_future(
                provisioner.install_agent(
                    connection=connection,
                    nonce=params.nonce,
                    machine_id=machine_id,
                    proxy=self.api_proxy,
                    series=params.series,
                )
            )

            machine = None
            for _ in range(10):
                machine_list = await model.get_machines()
                if machine_id in machine_list:
                    self.log.debug("Machine {} found in model!".format(machine_id))
                    machine = model.machines.get(machine_id)
                    break
                await asyncio.sleep(2)

            if machine is None:
                msg = "Machine {} not found in model".format(machine_id)
                self.log.error(msg=msg)
                raise JujuMachineNotFound(msg)

            self.log.debug(
                "Wait until machine {} is ready in model {}".format(
                    machine.entity_id, model_name
                )
            )
            await JujuModelWatcher.wait_for(
                model=model,
                entity=machine,
                progress_timeout=progress_timeout,
                total_timeout=total_timeout,
                db_dict=db_dict,
                n2vc=self.n2vc,
            )
        except Exception as e:
            raise e
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

        self.log.debug(
            "Machine provisioned {} in model {}".format(machine_id, model_name)
        )

        return machine_id

    async def deploy(
        self, uri: str, model_name: str, wait: bool = True, timeout: float = 3600
    ):
        """
        Deploy bundle or charm: Similar to the juju CLI command `juju deploy`

        :param: uri:            Path or Charm Store uri in which the charm or bundle can be found
        :param: model_name:     Model name
        :param: wait:           Indicates whether to wait or not until all applications are active
        :param: timeout:        Time in seconds to wait until all applications are active
        """
        controller = await self.get_controller()
        model = await self.get_model(controller, model_name)
        try:
            await model.deploy(uri)
            if wait:
                await JujuModelWatcher.wait_for_model(model, timeout=timeout)
                self.log.debug("All units active in model {}".format(model_name))
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def deploy_charm(
        self,
        application_name: str,
        path: str,
        model_name: str,
        machine_id: str,
        db_dict: dict = None,
        progress_timeout: float = None,
        total_timeout: float = None,
        config: dict = None,
        series: str = None,
        num_units: int = 1,
    ):
        """Deploy charm

        :param: application_name:   Application name
        :param: path:               Local path to the charm
        :param: model_name:         Model name
        :param: machine_id          ID of the machine
        :param: db_dict:            Dictionary with data of the DB to write the updates
        :param: progress_timeout:   Maximum time between two updates in the model
        :param: total_timeout:      Timeout for the entity to be active
        :param: config:             Config for the charm
        :param: series:             Series of the charm
        :param: num_units:          Number of units

        :return: (juju.application.Application): Juju application
        """
        self.log.debug(
            "Deploying charm {} to machine {} in model ~{}".format(
                application_name, machine_id, model_name
            )
        )
        self.log.debug("charm: {}".format(path))

        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)

        try:
            application = None
            if application_name not in model.applications:

                if machine_id is not None:
                    if machine_id not in model.machines:
                        msg = "Machine {} not found in model".format(machine_id)
                        self.log.error(msg=msg)
                        raise JujuMachineNotFound(msg)
                    machine = model.machines[machine_id]
                    series = machine.series

                application = await model.deploy(
                    entity_url=path,
                    application_name=application_name,
                    channel="stable",
                    num_units=1,
                    series=series,
                    to=machine_id,
                    config=config,
                )

                self.log.debug(
                    "Wait until application {} is ready in model {}".format(
                        application_name, model_name
                    )
                )
                if num_units > 1:
                    for _ in range(num_units - 1):
                        m, _ = await self.create_machine(model_name, wait=False)
                        await application.add_unit(to=m.entity_id)

                await JujuModelWatcher.wait_for(
                    model=model,
                    entity=application,
                    progress_timeout=progress_timeout,
                    total_timeout=total_timeout,
                    db_dict=db_dict,
                    n2vc=self.n2vc,
                )
                self.log.debug(
                    "Application {} is ready in model {}".format(
                        application_name, model_name
                    )
                )
            else:
                raise JujuApplicationExists(
                    "Application {} exists".format(application_name)
                )
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

        return application

    def _get_application(self, model: Model, application_name: str) -> Application:
        """Get application

        :param: model:              Model object
        :param: application_name:   Application name

        :return: juju.application.Application (or None if it doesn't exist)
        """
        if model.applications and application_name in model.applications:
            return model.applications[application_name]

    async def execute_action(
        self,
        application_name: str,
        model_name: str,
        action_name: str,
        db_dict: dict = None,
        progress_timeout: float = None,
        total_timeout: float = None,
        **kwargs,
    ):
        """Execute action

        :param: application_name:   Application name
        :param: model_name:         Model name
        :param: action_name:        Name of the action
        :param: db_dict:            Dictionary with data of the DB to write the updates
        :param: progress_timeout:   Maximum time between two updates in the model
        :param: total_timeout:      Timeout for the entity to be active

        :return: (str, str): (output and status)
        """
        self.log.debug(
            "Executing action {} using params {}".format(action_name, kwargs)
        )
        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)

        try:
            # Get application
            application = self._get_application(
                model,
                application_name=application_name,
            )
            if application is None:
                raise JujuApplicationNotFound("Cannot execute action")

            # Get leader unit
            # Racing condition:
            #   Ocassionally, self._get_leader_unit() will return None
            #   because the leader elected hook has not been triggered yet.
            #   Therefore, we are doing some retries. If it happens again,
            #   re-open bug 1236
            attempts = 3
            time_between_retries = 10
            unit = None
            for _ in range(attempts):
                unit = await self._get_leader_unit(application)
                if unit is None:
                    await asyncio.sleep(time_between_retries)
                else:
                    break
            if unit is None:
                raise JujuLeaderUnitNotFound(
                    "Cannot execute action: leader unit not found"
                )

            actions = await application.get_actions()

            if action_name not in actions:
                raise JujuActionNotFound(
                    "Action {} not in available actions".format(action_name)
                )

            action = await unit.run_action(action_name, **kwargs)

            self.log.debug(
                "Wait until action {} is completed in application {} (model={})".format(
                    action_name, application_name, model_name
                )
            )
            await JujuModelWatcher.wait_for(
                model=model,
                entity=action,
                progress_timeout=progress_timeout,
                total_timeout=total_timeout,
                db_dict=db_dict,
                n2vc=self.n2vc,
            )

            output = await model.get_action_output(action_uuid=action.entity_id)
            status = await model.get_action_status(uuid_or_prefix=action.entity_id)
            status = (
                status[action.entity_id] if action.entity_id in status else "failed"
            )

            self.log.debug(
                "Action {} completed with status {} in application {} (model={})".format(
                    action_name, action.status, application_name, model_name
                )
            )
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

        return output, status

    async def get_actions(self, application_name: str, model_name: str) -> dict:
        """Get list of actions

        :param: application_name: Application name
        :param: model_name: Model name

        :return: Dict with this format
            {
                "action_name": "Description of the action",
                ...
            }
        """
        self.log.debug(
            "Getting list of actions for application {}".format(application_name)
        )

        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)

        try:
            # Get application
            application = self._get_application(
                model,
                application_name=application_name,
            )

            # Return list of actions
            return await application.get_actions()

        finally:
            # Disconnect from model and controller
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def get_metrics(self, model_name: str, application_name: str) -> dict:
        """Get the metrics collected by the VCA.

        :param model_name The name or unique id of the network service
        :param application_name The name of the application
        """
        if not model_name or not application_name:
            raise Exception("model_name and application_name must be non-empty strings")
        metrics = {}
        controller = await self.get_controller()
        model = await self.get_model(controller, model_name)
        try:
            application = self._get_application(model, application_name)
            if application is not None:
                metrics = await application.get_metrics()
        finally:
            self.disconnect_model(model)
            self.disconnect_controller(controller)
        return metrics

    async def add_relation(
        self,
        model_name: str,
        endpoint_1: str,
        endpoint_2: str,
    ):
        """Add relation

        :param: model_name:     Model name
        :param: endpoint_1      First endpoint name
                                ("app:endpoint" format or directly the saas name)
        :param: endpoint_2:     Second endpoint name (^ same format)
        """

        self.log.debug("Adding relation: {} -> {}".format(endpoint_1, endpoint_2))

        # Get controller
        controller = await self.get_controller()

        # Get model
        model = await self.get_model(controller, model_name)

        # Add relation
        try:
            await model.add_relation(endpoint_1, endpoint_2)
        except juju.errors.JujuAPIError as e:
            if "not found" in e.message:
                self.log.warning("Relation not found: {}".format(e.message))
                return
            if "already exists" in e.message:
                self.log.warning("Relation already exists: {}".format(e.message))
                return
            # another exception, raise it
            raise e
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def consume(
        self,
        offer_url: str,
        model_name: str,
    ):
        """
        Adds a remote offer to the model. Relations can be created later using "juju relate".

        :param: offer_url:      Offer Url
        :param: model_name:     Model name

        :raises ParseError if there's a problem parsing the offer_url
        :raises JujuError if remote offer includes and endpoint
        :raises JujuAPIError if the operation is not successful
        """
        controller = await self.get_controller()
        model = await controller.get_model(model_name)

        try:
            await model.consume(offer_url)
        finally:
            await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def destroy_model(self, model_name: str, total_timeout: float):
        """
        Destroy model

        :param: model_name:     Model name
        :param: total_timeout:  Timeout
        """

        controller = await self.get_controller()
        model = None
        try:
            if not await self.model_exists(model_name, controller=controller):
                return

            model = await self.get_model(controller, model_name)
            self.log.debug("Destroying model {}".format(model_name))
            uuid = model.info.uuid

            # Destroy machines that are manually provisioned
            # and still are in pending state
            await self._destroy_pending_machines(model, only_manual=True)

            # Disconnect model
            await self.disconnect_model(model)

            await controller.destroy_model(uuid, force=True, max_wait=0)

            # Wait until model is destroyed
            self.log.debug("Waiting for model {} to be destroyed...".format(model_name))

            if total_timeout is None:
                total_timeout = 3600
            end = time.time() + total_timeout
            while time.time() < end:
                models = await controller.list_models()
                if model_name not in models:
                    self.log.debug(
                        "The model {} ({}) was destroyed".format(model_name, uuid)
                    )
                    return
                await asyncio.sleep(5)
            raise Exception(
                "Timeout waiting for model {} to be destroyed".format(model_name)
            )
        except Exception as e:
            if model:
                await self.disconnect_model(model)
            raise e
        finally:
            await self.disconnect_controller(controller)

    async def destroy_application(
        self, model_name: str, application_name: str, total_timeout: float
    ):
        """
        Destroy application

        :param: model_name:         Model name
        :param: application_name:   Application name
        :param: total_timeout:      Timeout
        """

        controller = await self.get_controller()
        model = None

        try:
            model = await self.get_model(controller, model_name)
            self.log.debug(
                "Destroying application {} in model {}".format(
                    application_name, model_name
                )
            )
            application = self._get_application(model, application_name)
            if application:
                await application.destroy()
            else:
                self.log.warning("Application not found: {}".format(application_name))

            self.log.debug(
                "Waiting for application {} to be destroyed in model {}...".format(
                    application_name, model_name
                )
            )
            if total_timeout is None:
                total_timeout = 3600
            end = time.time() + total_timeout
            while time.time() < end:
                if not self._get_application(model, application_name):
                    self.log.debug(
                        "The application {} was destroyed in model {} ".format(
                            application_name, model_name
                        )
                    )
                    return
                await asyncio.sleep(5)
            raise Exception(
                "Timeout waiting for application {} to be destroyed in model {}".format(
                    application_name, model_name
                )
            )
        finally:
            if model is not None:
                await self.disconnect_model(model)
            await self.disconnect_controller(controller)

    async def _destroy_pending_machines(self, model: Model, only_manual: bool = False):
        """
        Destroy pending machines in a given model

        :param: only_manual:    Bool that indicates only manually provisioned
                                machines should be destroyed (if True), or that
                                all pending machines should be destroyed
        """
        status = await model.get_status()
        for machine_id in status.machines:
            machine_status = status.machines[machine_id]
            if machine_status.agent_status.status == "pending":
                if only_manual and not machine_status.instance_id.startswith("manual:"):
                    break
                machine = model.machines[machine_id]
                await machine.destroy(force=True)

    async def configure_application(
        self, model_name: str, application_name: str, config: dict = None
    ):
        """Configure application

        :param: model_name:         Model name
        :param: application_name:   Application name
        :param: config:             Config to apply to the charm
        """
        self.log.debug("Configuring application {}".format(application_name))

        if config:
            controller = await self.get_controller()
            model = None
            try:
                model = await self.get_model(controller, model_name)
                application = self._get_application(
                    model,
                    application_name=application_name,
                )
                await application.set_config(config)
            finally:
                if model:
                    await self.disconnect_model(model)
                await self.disconnect_controller(controller)

    def _get_api_endpoints_db(self) -> [str]:
        """
        Get API Endpoints from DB

        :return: List of API endpoints
        """
        self.log.debug("Getting endpoints from database")

        juju_info = self.db.get_one(
            DB_DATA.api_endpoints.table,
            q_filter=DB_DATA.api_endpoints.filter,
            fail_on_empty=False,
        )
        if juju_info and DB_DATA.api_endpoints.key in juju_info:
            return juju_info[DB_DATA.api_endpoints.key]

    def _update_api_endpoints_db(self, endpoints: [str]):
        """
        Update API endpoints in Database

        :param: List of endpoints
        """
        self.log.debug("Saving endpoints {} in database".format(endpoints))

        juju_info = self.db.get_one(
            DB_DATA.api_endpoints.table,
            q_filter=DB_DATA.api_endpoints.filter,
            fail_on_empty=False,
        )
        # If it doesn't, then create it
        if not juju_info:
            try:
                self.db.create(
                    DB_DATA.api_endpoints.table,
                    DB_DATA.api_endpoints.filter,
                )
            except DbException as e:
                # Racing condition: check if another N2VC worker has created it
                juju_info = self.db.get_one(
                    DB_DATA.api_endpoints.table,
                    q_filter=DB_DATA.api_endpoints.filter,
                    fail_on_empty=False,
                )
                if not juju_info:
                    raise e
        self.db.set_one(
            DB_DATA.api_endpoints.table,
            DB_DATA.api_endpoints.filter,
            {DB_DATA.api_endpoints.key: endpoints},
        )

    def handle_exception(self, loop, context):
        # All unhandled exceptions by libjuju are handled here.
        pass

    async def health_check(self, interval: float = 300.0):
        """
        Health check to make sure controller and controller_model connections are OK

        :param: interval: Time in seconds between checks
        """
        controller = None
        while True:
            try:
                controller = await self.get_controller()
                # self.log.debug("VCA is alive")
            except Exception as e:
                self.log.error("Health check to VCA failed: {}".format(e))
            finally:
                await self.disconnect_controller(controller)
            await asyncio.sleep(interval)

    async def list_models(self, contains: str = None) -> [str]:
        """List models with certain names

        :param: contains:   String that is contained in model name

        :retur: [models] Returns list of model names
        """

        controller = await self.get_controller()
        try:
            models = await controller.list_models()
            if contains:
                models = [model for model in models if contains in model]
            return models
        finally:
            await self.disconnect_controller(controller)

    async def list_offers(self, model_name: str) -> QueryApplicationOffersResults:
        """List models with certain names

        :param: model_name: Model name

        :return:            Returns list of offers
        """

        controller = await self.get_controller()
        try:
            return await controller.list_offers(model_name)
        finally:
            await self.disconnect_controller(controller)

    async def add_k8s(
        self,
        name: str,
        rbac_id: str,
        token: str,
        client_cert_data: str,
        configuration: Configuration,
        storage_class: str,
        credential_name: str = None,
    ):
        """
        Add a Kubernetes cloud to the controller

        Similar to the `juju add-k8s` command in the CLI

        :param: name:               Name for the K8s cloud
        :param: configuration:      Kubernetes configuration object
        :param: storage_class:      Storage Class to use in the cloud
        :param: credential_name:    Storage Class to use in the cloud
        """

        if not storage_class:
            raise Exception("storage_class must be a non-empty string")
        if not name:
            raise Exception("name must be a non-empty string")
        if not configuration:
            raise Exception("configuration must be provided")

        endpoint = configuration.host
        credential = self.get_k8s_cloud_credential(
            configuration,
            client_cert_data,
            token,
        )
        credential.attrs[RBAC_LABEL_KEY_NAME] = rbac_id
        cloud = client.Cloud(
            type_="kubernetes",
            auth_types=[credential.auth_type],
            endpoint=endpoint,
            ca_certificates=[client_cert_data],
            config={
                "operator-storage": storage_class,
                "workload-storage": storage_class,
            },
        )

        return await self.add_cloud(
            name, cloud, credential, credential_name=credential_name
        )

    def get_k8s_cloud_credential(
        self,
        configuration: Configuration,
        client_cert_data: str,
        token: str = None,
    ) -> client.CloudCredential:
        attrs = {}
        # TODO: Test with AKS
        key = None  # open(configuration.key_file, "r").read()
        username = configuration.username
        password = configuration.password

        if client_cert_data:
            attrs["ClientCertificateData"] = client_cert_data
        if key:
            attrs["ClientKeyData"] = key
        if token:
            if username or password:
                raise JujuInvalidK8sConfiguration("Cannot set both token and user/pass")
            attrs["Token"] = token

        auth_type = None
        if key:
            auth_type = "oauth2"
            if client_cert_data:
                auth_type = "oauth2withcert"
            if not token:
                raise JujuInvalidK8sConfiguration(
                    "missing token for auth type {}".format(auth_type)
                )
        elif username:
            if not password:
                self.log.debug(
                    "credential for user {} has empty password".format(username)
                )
            attrs["username"] = username
            attrs["password"] = password
            if client_cert_data:
                auth_type = "userpasswithcert"
            else:
                auth_type = "userpass"
        elif client_cert_data and token:
            auth_type = "certificate"
        else:
            raise JujuInvalidK8sConfiguration("authentication method not supported")
        return client.CloudCredential(auth_type=auth_type, attrs=attrs)

    async def add_cloud(
        self,
        name: str,
        cloud: Cloud,
        credential: CloudCredential = None,
        credential_name: str = None,
    ) -> Cloud:
        """
        Add cloud to the controller

        :param: name:               Name of the cloud to be added
        :param: cloud:              Cloud object
        :param: credential:         CloudCredentials object for the cloud
        :param: credential_name:    Credential name.
                                    If not defined, cloud of the name will be used.
        """
        controller = await self.get_controller()
        try:
            _ = await controller.add_cloud(name, cloud)
            if credential:
                await controller.add_credential(
                    credential_name or name, credential=credential, cloud=name
                )
            # Need to return the object returned by the controller.add_cloud() function
            # I'm returning the original value now until this bug is fixed:
            #   https://github.com/juju/python-libjuju/issues/443
            return cloud
        finally:
            await self.disconnect_controller(controller)

    async def remove_cloud(self, name: str):
        """
        Remove cloud

        :param: name:   Name of the cloud to be removed
        """
        controller = await self.get_controller()
        try:
            await controller.remove_cloud(name)
        except juju.errors.JujuError as e:
            if len(e.errors) == 1 and f'cloud "{name}" not found' == e.errors[0]:
                self.log.warning(f"Cloud {name} not found, so it could not be deleted.")
            else:
                raise e
        finally:
            await self.disconnect_controller(controller)

    async def _get_leader_unit(self, application: Application) -> Unit:
        unit = None
        for u in application.units:
            if await u.is_leader_from_status():
                unit = u
                break
        return unit

    async def get_cloud_credentials(self, cloud_name: str, credential_name: str):
        controller = await self.get_controller()
        try:
            facade = client.CloudFacade.from_connection(controller.connection())
            cloud_cred_tag = tag.credential(cloud_name, self.username, credential_name)
            params = [client.Entity(cloud_cred_tag)]
            return (await facade.Credential(params)).results
        finally:
            await self.disconnect_controller(controller)