import os
import math
from pathlib import Path

from files import get_pictures

def rename_num(entries, reverse=False):
    """Rename file, on the fly"""
    entries = sorted(entries, key=lambda entry: entry.name, reverse=reverse)
    digit_length = int(math.log10(len(entries)) + 1)
    renamed = {}
    for i, entry in enumerate(entries):
        renamed[entry] = '{number:0{width}d}{ext}'.format(number=i,width=digit_length,ext=Path(entry.path).suffix)
    for src, dst in renamed.items():
       os.rename(src, dst)