import os

from ucloud.shared import shared
from ucloud.settings import settings


class Optional:
    pass


class Field:
    def __init__(self, _name, _type, _value=None):
        self.name = _name
        self.value = _value
        self.type = _type
        self.__errors = []

    def validation(self):
        return True

    def is_valid(self):
        if self.value == KeyError:
            self.add_error(
                "'{}' field is a required field".format(self.name)
            )
        else:
            if isinstance(self.value, Optional):
                pass
            elif not isinstance(self.value, self.type):
                self.add_error(
                    "Incorrect Type for '{}' field".format(self.name)
                )
            else:
                self.validation()

        if self.__errors:
            return False
        return True

    def get_errors(self):
        return self.__errors

    def add_error(self, error):
        self.__errors.append(error)


class VmUUIDField(Field):
    def __init__(self, data):
        self.uuid = data.get("uuid", KeyError)

        super().__init__("uuid", str, self.uuid)

        self.validation = self.vm_uuid_validation

    def vm_uuid_validation(self):
        r = shared.etcd_client.get(
            os.path.join(settings["etcd"]["vm_prefix"], self.uuid)
        )
        if not r:
            self.add_error(
                "VM with uuid {} does not exists".format(self.uuid)
            )