from xos.exceptions import XOSValidationError

from models_decl import ProgranService_decl
from models_decl import ENodeB_decl
from models_decl import Handover_decl
from models_decl import ProgranServiceInstance_decl


class ProgranService(ProgranService_decl):
    class Meta:
        proxy = True
    def save(self, *args, **kwargs):

        existing_services = ProgranService.objects.all()

        if len(existing_services) > 0 and not self.delete:
            raise XOSValidationError("A ProgranService already exists, you should not have more than one")

        super(ProgranService, self).save(*args, **kwargs)


class ENodeB(ENodeB_decl):
    class Meta:
        proxy = True

    ## TODO do not allow enbId duplicates


class Handover(Handover_decl):
    class Meta:
        proxy = True


class ProgranServiceInstance(ProgranServiceInstance_decl):
    class Meta:
        proxy = True

    def save(self, *args, **kwargs):
        # NOTE someone is setting owner_id, so just override it for now
        try:
            # NOTE we allow just one ProgranService
            progran_service = ProgranService.objects.all()[0]
            self.owner_id = progran_service.id
        except IndexError:
            raise XOSValidationError("Service Progran cannot be found, please make sure that the model exists.")

        # NOTE if the instance is new, check that the name is not duplicated
        instances_with_same_name = None
        # FIXME This may leave us vulnerable to someone changing the name at a later time and causing a conflict.
        # If that's important to prevent, we could prevent that case when `self.pk!=None`,
        # filter for ProgranServiceInstance with the same name but `pk!=self.pk`.
        if self.pk is None:
            try:
                instances_with_same_name = ProgranServiceInstance.objects.get(name=self.name)
            except self.DoesNotExist:
                # it's ok not to find anything here
                pass

        if instances_with_same_name:
            raise XOSValidationError("A ProgranServiceInstance with name '%s' already exists" % self.name)
        super(ProgranServiceInstance, self).save(*args, **kwargs)