from abc import abstractmethod
from typing import Optional, NoReturn, Union

import datasets


class FSConfig(datasets.BuilderConfig):
    """BuilderConfig for FS."""

    def __init__(self, additional_features, data_url, citation, url, **kwargs):
        """BuilderConfig for FS.
        Args:
          additional_features: `list[string]`, list of the features that will appear in the feature dict
           additionally to the self.id_key, self.source_key and self.target_key. Should not include "label".
          data_url: `string`, url to download the zip file from.
          citation: `string`, citation for the data set.
          url: `string`, url for information about the data set.
          label_classes: `list[string]`, the list of classes for the label if the
            label is present as a string. Non-string labels will be cast to either
            'False' or 'True'.
          **kwargs: keyword arguments forwarded to super.
        """
        super(FSConfig, self).__init__(version=datasets.Version("1.0.0"), **kwargs)
        self.features = [self.id_key, self.source_key, self.target_key] + additional_features
        if self.question_key:
            self.features += [self.question_key]
        self.data_url = data_url
        self.citation = citation
        self.url = url

    @property
    @abstractmethod
    def id_key(self) -> str:
        pass

    @property
    @abstractmethod
    def train_file(self) -> str:
        pass

    @property
    @abstractmethod
    def validation_file(self) -> str:
        pass

    @property
    @abstractmethod
    def test_file(self) -> str:
        pass

    @property
    @abstractmethod
    def source_key(self) -> str:
        pass

    @property
    def question_key(self) -> Union[str, None]:
        return None

    @property
    @abstractmethod
    def target_key(self) -> str:
        pass

    def process(self, example) -> NoReturn:
        pass