import numpy as np
import torch

import utils.pytorch_util as ptu


def eval_np(module, *args, **kwargs):
    """
    Eval this module with a numpy interface

    Same as a call to __call__ except all Variable input/outputs are
    replaced with numpy equivalents.

    Assumes the output is either a single object or a tuple of objects.
    """
    torch_args = tuple(torch_ify(x) for x in args)
    torch_kwargs = {k: torch_ify(v) for k, v in kwargs.items()}
    outputs = module(*torch_args, **torch_kwargs)
    if isinstance(outputs, tuple):
        return tuple(np_ify(x) for x in outputs)
    else:
        return np_ify(outputs)


def torch_ify(np_array_or_other):
    if isinstance(np_array_or_other, np.ndarray):
        return ptu.from_numpy(np_array_or_other)
    else:
        return np_array_or_other


def np_ify(tensor_or_other):
    if isinstance(tensor_or_other, torch.autograd.Variable):
        return ptu.get_numpy(tensor_or_other)
    else:
        return tensor_or_other


def _elem_or_tuple_to_variable(elem_or_tuple):
    if isinstance(elem_or_tuple, tuple):
        return tuple(
            _elem_or_tuple_to_variable(e) for e in elem_or_tuple
        )
    return ptu.from_numpy(elem_or_tuple).float()


def _filter_batch(np_batch):
    for k, v in np_batch.items():
        if v.dtype == np.bool:
            yield k, v.astype(int)
        else:
            yield k, v


def np_to_pytorch_batch(np_batch):
    return {
        k: _elem_or_tuple_to_variable(x)
        for k, x in _filter_batch(np_batch)
        if x.dtype != np.dtype('O')  # ignore object (e.g. dictionaries)
    }
