#!/usr/bin/env python
from dataclasses import dataclass
from typing import Callable

__all__ = ['ModelZooRegistry', 'ModelAttribute', 'model_zoo']


@dataclass
class ModelAttribute:
    """
    Attributes of a model.

    Args:
        has_control_flow (bool): Whether the model contains branching in its forward method.
        has_stochastic_depth_prob (bool): Whether the model contains stochastic depth probability. Often seen in the torchvision models.
    """
    has_control_flow: bool = False
    has_stochastic_depth_prob: bool = False


class ModelZooRegistry(dict):
    """
    A registry to map model names to model and data generation functions.
    """

    def register(self,
                 name: str,
                 model_fn: Callable,
                 data_gen_fn: Callable,
                 output_transform_fn: Callable,
                 loss_fn: Callable = None,
                 model_attribute: ModelAttribute = None):
        """
        Register a model and data generation function.

        Examples:

        ```python
        # normal forward workflow
        model = resnet18()
        data = resnet18_data_gen()
        output = model(**data)
        transformed_output = output_transform_fn(output)
        loss = loss_fn(transformed_output)

        # Register
        model_zoo = ModelZooRegistry()
        model_zoo.register('resnet18', resnet18, resnet18_data_gen, output_transform_fn, loss_fn)
        ```

        Args:
            name (str): Name of the model.
            model_fn (Callable): A function that returns a model. **It must not contain any arguments.**
            data_gen_fn (Callable): A function that returns a data sample in the form of Dict. **It must not contain any arguments.**
            output_transform_fn (Callable): A function that transforms the output of the model into Dict.
            loss_fn (Callable): a function to compute the loss from the given output. Defaults to None
            model_attribute (ModelAttribute): Attributes of the model. Defaults to None.
        """
        self[name] = (model_fn, data_gen_fn, output_transform_fn, loss_fn, model_attribute)

    def get_sub_registry(self, keyword: str):
        """
        Get a sub registry with models that contain the keyword.

        Args:
            keyword (str): Keyword to filter models.
        """
        new_dict = dict()

        for k, v in self.items():
            if keyword in k:
                new_dict[k] = v

        assert len(new_dict) > 0, f'No model found with keyword {keyword}'
        return new_dict


model_zoo = ModelZooRegistry()
