#!/usr/bin/env python3
# pylint: disable=C0103

"""
From a list of subdomains, output only
the ones resolving to a first-party tracker.
"""

import argparse
import sys
import progressbar
import csv
import typing

import adblockparser

OPTIONS = {"third-party": True}


def subdomain_matching(subdomain: str) -> bool:
    url = f"https://{subdomain}/"
    return rules.should_block(url, OPTIONS)


def get_matching(chain: typing.List[str], no_explicit: bool = False
                 ) -> typing.Iterable[str]:
    initial = chain[0]
    cname_destinations = chain[1:-1]
    # a_destination = chain[-1]
    initial_matching = subdomain_matching(initial)
    if no_explicit and initial_matching:
        return
    cname_matching = any(map(subdomain_matching, cname_destinations))
    if cname_matching or initial_matching:
        yield initial


if __name__ == '__main__':

    # Parsing arguments
    parser = argparse.ArgumentParser(
        description="Filter first-party trackers from a list of subdomains")
    parser.add_argument(
        '-i', '--input', type=argparse.FileType('r'), default=sys.stdin,
        help="Input file with DNS chains")
    parser.add_argument(
        '-o', '--output', type=argparse.FileType('w'), default=sys.stdout,
        help="Outptut file with one tracking subdomain per line")
    parser.add_argument(
        '-n', '--no-explicit', action='store_true',
        help="Don't output domains already blocked with rules without CNAME")
    parser.add_argument(
        '-r', '--rules', type=argparse.FileType('r'), default='rules',
        help="Rules file")
    args = parser.parse_args()

    # Reading rules
    rules: adblockparser.AdblockRules = adblockparser.AdblockRules(args.rules)

    # Progress bar
    widgets = [
        progressbar.Percentage(),
        ' ', progressbar.SimpleProgress(),
        ' ', progressbar.Bar(),
        ' ', progressbar.Timer(),
        ' ', progressbar.AdaptiveTransferSpeed(unit='req'),
        ' ', progressbar.AdaptiveETA(),
    ]
    progress = progressbar.ProgressBar(widgets=widgets)
    if args.input.seekable():
        progress.max_value = len(args.input.readlines())
        args.input.seek(0)

    # Cleaning input
    reader = csv.reader(args.input)

    # Filtering
    progress.start()
    for chain in reader:
        for match in get_matching(chain, no_explicit=args.no_explicit):
            print(match, file=args.output)
        progress.update(progress.value + 1)
    progress.finish()