Mega.nz old to new format converter.

oldtonew.py

#!/usr/bin/env python3
import os
import re
import sys
import argparse

parser = argparse.ArgumentParser()
parser.add_argument("-u", "--url", nargs="+", required=True, help="URL or text filename.")
parser.add_argument("-o", "--output", help="Output text filename.")
args = parser.parse_args()


def exist_check(f, delete):
    if os.path.isfile(f):
        if delete:
            os.remove(f)
    elif not delete:
        print("Source text file doesn't exist.")
        sys.exit(1)

def read_txt():
    exist_check(args.url[0], False)
    with open(args.url[0]) as f:
        return f.readlines()

def write_txt(url):
    with open(args.output, "a") as f:
        f.write(url + "\n")

def main(url):
    regex = (
        "https://mega\.nz/(#!|#F!|folder|file)(?:/)?"
        "([a-zA-Z\d]{8})(?:!|#)([\w-]{22}|[\w-]{43})(?:/)?$"
    )
    m = re.match(regex, url)
    if not m:
        print("Invalid URL.")
        return
    print(url)
    try:
        media_type = {"#!": "file", "#F!": "folder"}[m.group(1)]
    except KeyError:
        print("Already in new format.")
        return
    new = "https://mega.nz/{}/{}#{}".format(media_type, m.group(2),
        m.group(3)
    )
    print("->", new)
    if args.output:
        write_txt(new)

if __name__ == "__main__":
    if args.output:
        exist_check(args.output, True)
    if args.url[0].endswith(".txt"):
        args.url = read_txt()
    for url in args.url:
        main(url.strip())