import time
from typing import Iterable
from uuid import uuid4
from yaml import load

from onapsdk.aai.business import Customer, ServiceInstance, ServiceSubscription
from onapsdk.configuration import settings
from onapsdk.so.instantiation import VnfParameter

from ..base import YamlTemplateBaseStep
from .vnf_ala_carte import YamlTemplateVnfAlaCarteInstantiateStep


class YamlTemplateVfModuleAlaCarteInstantiateStep(YamlTemplateBaseStep):
    """Instantiate vf module a'la carte using YAML template."""

    def __init__(self, cleanup=False):
        """Initialize step.

        Substeps:
            - YamlTemplateVnfAlaCarteInstantiateStep.
        """
        super().__init__(cleanup=cleanup)
        self._yaml_template: dict = None
        self.add_step(YamlTemplateVnfAlaCarteInstantiateStep(cleanup))

    @property
    def yaml_template(self) -> dict:
        """Step YAML template.

        Load from file if it's a root step, get from parent otherwise.

        Returns:
            dict: Step YAML template

        """
        if self.is_root:
            if not self._yaml_template:
                with open(settings.SERVICE_YAML_TEMPLATE, "r") as yaml_template:
                    self._yaml_template: dict = load(yaml_template)
            return self._yaml_template
        return self.parent.yaml_template

    @property
    def service_name(self) -> str:
        """Service name.

        Get from YAML template if it's a root step, get from parent otherwise.

        Returns:
            str: Service name

        """
        if self.is_root:
            return next(iter(self.yaml_template.keys()))
        return self.parent.service_name

    @property
    def service_instance_name(self) -> str:
        """Service instance name.

        Generate using `service_name` and `uuid4()` function if it's a root step,
            get from parent otherwise.

        Returns:
            str: Service instance name

        """
        if self.is_root:
            return f"{self.service_name}-{str(uuid4())}"
        return self.parent.service_instance_name

    def get_vnf_parameters(self, vnf_name: str) -> Iterable[VnfParameter]:
        """Get VNF parameters from YAML template.

        Args:
            vnf_name (str): VNF name to get parameters for.

        Yields:
            Iterator[Iterable[VnfParameter]]: VNF parameter

        """
        for vnf in self.yaml_template[self.service_name]["vnfs"]:
            if vnf["vnf_name"] == vnf_name:
                for vnf_parameter in vnf["vnf_parameters"]:
                    yield VnfParameter(
                        name=vnf_parameter["name"],
                        value=vnf_parameter["value"]
                    )

    def execute(self) -> None:
        """Instantiate Vf module.

        Use settings values:
         - GLOBAL_CUSTOMER_ID.

        Raises:
            Exception: Vf module instantiation failed

        """
        super().execute()
        customer: Customer = Customer.get_by_global_customer_id(settings.GLOBAL_CUSTOMER_ID)
        service_subscription: ServiceSubscription = customer.get_service_subscription_by_service_type(self.service_name)
        service_instance: ServiceInstance = service_subscription.get_service_instance_by_name(self.service_instance_name)
        for vnf_instance in service_instance.vnf_instances:
            vf_module_instantiation = vnf_instance.add_vf_module(
                vnf_instance.vnf.vf_module,
                vnf_parameters= self.get_vnf_parameters(vnf_instance.vnf.vnf_name))
            while not vf_module_instantiation.finished:
                time.sleep(10)
            if vf_module_instantiation.failed:
                raise Exception("Vf module instantiation failed")