"""Utility functions for Chiluka."""

import torch
from munch import Munch


def length_to_mask(lengths):
    """Convert lengths to attention mask."""
    mask = torch.arange(lengths.max()).unsqueeze(0).expand(lengths.shape[0], -1).type_as(lengths)
    mask = torch.gt(mask + 1, lengths.unsqueeze(1))
    return mask


def recursive_munch(d):
    """Recursively convert dict to Munch for dot notation access."""
    if isinstance(d, dict):
        return Munch((k, recursive_munch(v)) for k, v in d.items())
    elif isinstance(d, list):
        return [recursive_munch(v) for v in d]
    else:
        return d