# https://github.com/PeterDaveHello/top-1m-domains
urltop_default = "https://s3-us-west-1.amazonaws.com/umbrella-static/top-1m.csv.zip"
csvfn_default = "top-1m.csv"  # path within the zip file

one_week = 7 * 24 * 60 * 60  # in seconds


def alive(fp, expiry):
    from os.path import exists, getmtime, getsize
    from time import time

    # 2 is used as a magic number because it's len("\r\n")
    return exists(fp) and time() < getmtime(fp) + expiry and getsize(fp) > 2


def download_top1m(urltop=None, csvfn=None):
    from io import BytesIO
    from urllib.request import urlopen
    from zipfile import ZipFile

    if urltop is None:
        urltop = urltop_default
    if csvfn is None:
        csvfn = csvfn_default

    comp = BytesIO()
    with urlopen(urltop) as re:
        comp.write(re.read())

    comp.seek(0)
    with ZipFile(comp) as zipf:
        with zipf.open(csvfn) as f:
            uncomp = f.read()
    comp.close()

    return uncomp.decode("utf-8")


def retrieve_top1m_entries(csv_fp="top-1m.csv"):
    from sys import stderr

    if alive(csv_fp, one_week):
        with open(csv_fp, "r") as f:
            uncomp = f.read()
    else:
        print("downloading", csv_fp, file=stderr)
        uncomp = download_top1m()
        with open(csv_fp, "w") as f:
            f.write(uncomp)

    # we could use the csv module, but this is totally overkill
    # for data that *should* be just a subset of ascii.
    lines = uncomp.splitlines()
    entries = [(lambda a: (int(a[0]), a[2]))(line.partition(","))
               for line in lines if line]
    return entries