import logging
import config

from helper import resolve_product_usable_id

etcd_client = config.etcd_client


class ValidationException(Exception):
    """Validation Error"""


class Field:
    def __init__(self, _name, _type, _value=None, validators=None):
        if validators is None:
            validators = []

        assert isinstance(validators, list)

        self.name = _name
        self.value = _value
        self.type = _type
        self.validators = validators

    def is_valid(self):
        if not isinstance(self.value, self.type):
            try:
                self.value = self.type(self.value)
            except Exception:
                raise ValidationException("Incorrect Type for '{}' field".format(self.name))

        for validator in self.validators:
            validator()

    def __repr__(self):
        return self.name


class BaseSchema:
    def __init__(self):
        self.fields = [getattr(self, field) for field in dir(self) if isinstance(getattr(self, field), Field)]

    def validation(self):
        # custom validation is optional
        return True

    def is_valid(self):
        for field in self.fields:
            field.is_valid()

        for parent in self.__class__.__bases__:
            parent.validation(self)

        self.validation()

        for field in self.fields:
            setattr(self, field.name, field.value)

    def return_data(self):
        return {
            field.name: field.value
            for field in self.fields
        }


def get(dictionary: dict, key: str, return_default=False, default=None):
    if dictionary is None:
        raise ValidationException('No data provided at all.')
    try:
        value = dictionary[key]
    except KeyError:
        if return_default:
            return default
        raise ValidationException("Missing data for '{}' field.".format(key))
    else:
        return value


class AddProductSchema(BaseSchema):
    def __init__(self, data):
        self.email = Field('email', str, get(data, 'email'))
        self.password = Field('password', str, get(data, 'password'))
        self.specs = Field('specs', dict, get(data, 'specs'))
        super().__init__()


class UserRegisterPaymentSchema(BaseSchema):
    def __init__(self, data):
        self.email = Field('email', str, get(data, 'email'))
        self.password = Field('password', str, get(data, 'password'))
        self.card_number = Field('card_number', str, get(data, 'card_number'))
        self.cvc = Field('cvc', str, get(data, 'cvc'))
        self.expiry_year = Field('expiry_year', int, get(data, 'expiry_year'))
        self.expiry_month = Field('expiry_month', int, get(data, 'expiry_month'))
        self.card_holder_name = Field('card_holder_name', str, get(data, 'card_holder_name'))

        super().__init__()


class ProductOrderSchema(BaseSchema):
    def __init__(self, data):
        self.email = Field('email', str, get(data, 'email'))
        self.password = Field('password', str, get(data, 'password'))
        self.product_id = Field('product_id', str, get(data, 'product_id'), validators=[self.product_id_validation])

        super().__init__()

    def product_id_validation(self):
        product_uuid = resolve_product_usable_id(self.product_id.value, etcd_client)
        if product_uuid:
            self.product_id.value = product_uuid
        else:
            raise ValidationException('Invalid Product ID')


class OrderListSchema(BaseSchema):
    def __init__(self, data):
        self.email = Field('email', str, get(data, 'email'))
        self.password = Field('password', str, get(data, 'password'))
        super().__init__()

def make_return_message(err, status_code=200):
    logging.debug('message: {}'.format(str(err)))
    return {'message': str(err)}, status_code


def create_schema(specification, data):
    fields = {}
    for feature_name, feature_detail in specification['features'].items():
        if not feature_detail['constant']:
            fields[feature_name] = Field(feature_name, eval(feature_detail['unit']['type']), get(data, feature_name))

    return type('{}Schema'.format(specification['name']), (BaseSchema,), fields)