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import os
from pathlib import Path
from typing import Optional

import numpy as np

import torch
from scipy.io.wavfile import read


def mask_from_lens(lens, max_len: Optional[int] = None):
    if max_len is None:
        max_len = int(lens.max().item())
    ids = torch.arange(0, max_len, device=lens.device, dtype=lens.dtype)
    mask = torch.lt(ids, lens.unsqueeze(1))
    return mask


def load_wav_to_torch(full_path):
    sampling_rate, data = read(full_path)
    return torch.FloatTensor(data.astype(np.float32)), sampling_rate


def load_filepaths_and_text(dataset_path, filename, split="|"):
    def split_line(root, line):
        parts = line.strip().split(split)
        paths, text = parts[:-1], parts[-1]
        return tuple(os.path.join(root, p) for p in paths) + (text,)
    with open(filename, encoding='utf-8') as f:
        filepaths_and_text = [split_line(dataset_path, line) for line in f]
    return filepaths_and_text


def stats_filename(dataset_path, filelist_path, feature_name):
    stem = Path(filelist_path).stem
    return Path(dataset_path, f'{feature_name}_stats__{stem}.json')


def to_device_async(tensor, device):
    return tensor.to(device, non_blocking=True)


def to_numpy(x):
    return x.cpu().numpy() if isinstance(x, torch.Tensor) else x