# Copyright (c) 2022 Graphcore Ltd. All rights reserved.
import abc
from typing import Callable, Tuple
import tensorflow as tf


class AbstractDataset(abc.ABC):
    @abc.abstractmethod
    def read_single_image(self) -> tf.data.Dataset:
        raise NotImplementedError("Each dataset must provide an implementation of read_single_image")

    @abc.abstractmethod
    def size(self) -> int:
        raise NotImplementedError("Each dataset must provide an implementation of size")

    @abc.abstractmethod
    def image_shape(self) -> Tuple:
        raise NotImplementedError("Each dataset must provide an implementation of image_shape")

    @abc.abstractmethod
    def num_classes(self) -> int:
        raise NotImplementedError("Each dataset must provide an implementation of num_classes")

    @abc.abstractmethod
    def cpu_preprocessing_fn(self) -> Callable:
        raise NotImplementedError("Each dataset must provide an implementation of process_image")

    @abc.abstractmethod
    def ipu_preprocessing_fn(self) -> Callable:
        raise NotImplementedError("Each dataset must provide an implementation of ipu_preprocessing_fn")