import os

from tqdm import tqdm
import requests


def d(url, dst, desc=None):
    file_size = requests.head(url).headers.get("Content-Length", '-1')
    file_size = int(file_size)
    if os.path.exists(dst):
        first_byte = os.path.getsize(dst)
    else:
        first_byte = 0
    if first_byte > file_size:
        first_byte = 0
    elif first_byte == file_size:
        return file_size
    header = {"Range": "bytes=%s-%s" % (first_byte, file_size)}
    desc = desc or url.split('/')[-1]
    pbar = tqdm(
        total=file_size,
        initial=first_byte,
        ncols=75,
        unit='B', unit_scale=True, unit_divisor=1024,
        desc=desc)
    req = requests.get(url, headers=header, stream=True)
    with(open(dst, 'ab')) as f:
        for chunk in req.iter_content(chunk_size=1024):
            if chunk:
                f.write(chunk)
                pbar.update(1024)
    pbar.close()
    return file_size