#!/usr/bin/env python3

import csv
import fileinput
from functools import lru_cache
from hashlib import sha1
from urllib.request import Request, urlopen


def get_credentials():
    with fileinput.input() as csvfile:
        for credential in csv.DictReader(csvfile, delimiter=',', quotechar='"'):
            if credential.get('password'):
                yield credential


def get_hash(password):
    checksum = sha1(password.encode()).hexdigest().upper()
    return checksum[:5], checksum[5:]


@lru_cache(maxsize=4096)
def get_range(prefix):
    request = Request('https://api.pwnedpasswords.com/range/{}'.format(prefix))
    request.add_header('User-Agent', 'tenzers-pwned-passwords-checker (+https://gist.github.com/Tenzer/b8aa3cfa09a7e1396a0661de6bf35633)')
    response = urlopen(request, timeout=10).read()
    data = dict()
    for line in response.decode().splitlines():
        split_line = line.split(':')
        data[split_line[0]] = split_line[1]
    return data


def main():
    for credential in get_credentials():
        prefix, suffix = get_hash(credential['password'])
        range_data = get_range(prefix)
        if range_data.get(suffix):
            print(
                '{} occurrences found of the password for "{}"'.format(
                    range_data.get(suffix),
                    credential.get('name'),
                )
            )


if __name__ == '__main__':
    main()