from abc import ABC, abstractmethod
from typing import List, Tuple, Optional, TypeVar, Type

from text_generation.models.types import Batch, GeneratedText

B = TypeVar("B", bound=Batch)


class Model(ABC):
    @property
    @abstractmethod
    def batch_type(self) -> Type[B]:
        raise NotImplementedError

    @abstractmethod
    def generate_token(
            self, batch: B
    ) -> Tuple[List[GeneratedText], Optional[B]]:
        raise NotImplementedError