import os
import sys
import re
import hashlib
import math
import getopt
import requests
import colorama
from torf import Torrent

index_path = '/backup-index.html'
status_path = '/:db:/:date:/dumpstatus.json'
mirrors = ['https://dumps.wikimedia.org',
           'https://ftp.acc.umu.se/mirror/wikimedia.org/dumps',
           'https://dumps.wikimedia.your.org']
trackers = ['udp://tracker.opentrackr.org:1337/announce',
            'udp://tracker.openbittorrent.com:6969',
            'udp://explodie.org:6969']
prev_progress = 0


def main():
    colorama.init()
    try:
        opts, args = getopt.gnu_getopt(sys.argv, "hm:d:", ["help", "mirror=", "date="])
    except getopt.GetoptError:
        show_usage()
        sys.exit(-2)
    mirror = mirrors[0]
    date = ''
    for arg, value in opts:
        if arg == "-h" or arg == "--help":
            show_usage()
            sys.exit(-2)
        elif arg == "-m" or arg == "--mirror":
            v = int(value)
            mirror = mirrors[v]
        elif arg == "-d" or arg == "--date":
            date = date_from_opt(value)
    if len(args) != 2:
        show_usage()
        sys.exit(-2)
    db = args[1]
    if date == '':
        date = find_last_date(mirror, db)
    print(f'Preparing torrent for wikipedia\'s {db} articles dump recombine dating {date_format(date)}.\n')
    recombine = get_job_state(mirror, db, date, 'articlesmultistreamdumprecombine')
    if recombine['status'] != 'done':
        print('"articles dump recombine" job is not done yet!')
        sys.exit(-1)
    dir_name = f'{db}-{date}-pages-articles-multistream'
    try:
        os.mkdir(dir_name)
    except OSError as error:
        print(error)
    expected_file_name1 = f'{db}-{date}-pages-articles-multistream-index.txt.bz2'
    file1 = recombine['files'][expected_file_name1]
    path1 = file1['url']
    download_file(f'{dir_name}/{expected_file_name1}', f'{mirror}{path1}', file1['size'])
    verify_checksum(f'{dir_name}/{expected_file_name1}', file1['sha1'], file1['size'])
    expected_file_name2 = f'{db}-{date}-pages-articles-multistream.xml.bz2'
    file2 = recombine['files'][expected_file_name2]
    path2 = file2['url']
    download_file(f'{dir_name}/{expected_file_name2}', f'{mirror}{path2}', file2['size'])
    verify_checksum(f'{dir_name}/{expected_file_name2}', file2['sha1'], file2['size'])
    # webseeds = [
    #     f'{mirrors[0]}{path}',
    #     f'{mirrors[1]}{path}',
    # ]
    torrent = Torrent(path=dir_name, trackers=trackers)
    print('Creating torrent file...', end='')
    torrent.generate()
    torrent.write(f'{dir_name}.torrent')
    print('Done')


def date_from_opt(from_opt: str):
    r = r'\d{4}-\d{2}-\d{2}'
    if re.match(r, from_opt) is None:
        show_usage()
        sys.exit(-2)
    return from_opt.replace('-', '')


def date_format(date):
    return f'{date[:4]}-{date[4:6]}-{date[6:]}'


def verify_checksum(filename, expected, size):
    print(f'Checking checksum of {filename} ', end='', flush=True)
    show_progress(0)
    h = hashlib.sha1()
    one_percent = size / 100
    next_percent = one_percent
    with open(filename, 'rb') as fd:
        done = 0
        for chunk in fd:
            h.update(chunk)
            done += len(chunk)
            if done >= next_percent:
                next_percent += one_percent
                show_progress(int(done * 100 / size))
    rc = h.hexdigest()
    if rc != expected:
        print(' Bad', flush=True)
        sys.exit(-1)
    print(' Ok', flush=True)


def get_job_state(base_uri, db, date, jobname):
    path = status_path.replace(':db:', db).replace(':date:', date)
    page = requests.get(f'{base_uri}{path}')
    state = page.json()
    jobs = state['jobs']
    return jobs[jobname]


def download_file(filename, uri, size):
    with open(filename, 'ab') as fd:
        start_from = fd.tell()
        if start_from == size:
            headers = None
        elif start_from > 0:
            headers = {'Range': f'bytes={start_from}-'}
        else:
            headers = {}
        print(f'Downloading {uri} ', end='', flush=True)
        one_percent = size / 100
        next_percent = start_from + one_percent
        show_progress(0)
        if start_from >= one_percent:
            for p in range(1, math.ceil(start_from * 100 / size) + 1):
                show_progress(p)
        if headers is not None:
            done = start_from
            file = requests.get(uri, headers=headers, stream=True)
            for chunk in file.iter_content(16384):
                fd.write(chunk)
                done += len(chunk)
                if done >= next_percent:
                    next_percent += one_percent
                    show_progress(int(done * 100 / size))
    print(" Done", flush=True)


def show_progress(percent: int):
    is_tty = sys.stdout.isatty()
    if percent == 0 and is_tty:
        print('  0%', end='', flush=True)
    elif is_tty:
        print(f"\033[4D{percent:3d}%", end='', flush=True)
    elif percent != 0:
        print('.', end='', flush=True)


def find_last_date(base_uri, db):
    page = requests.get(f'{base_uri}{index_path}')
    r = re.compile(f'<a href="{db}/(.+)">')
    found = re.findall(r, page.text)
    return found[0]


def show_usage():
    print('Wrong usage')
    print('Usage', sys.argv[0], '[db] [options...]')
    print('Options:')
    print(' -m, --mirror\tUse mirror number (see list bellow)')
    print(' -d, --date\t\tDump date (i.e. 2020-11-01)')
    print()
    print('Mirrors:')
    i = 0
    for mirror in mirrors:
        print(i, mirror)
        i += 1


if __name__ == '__main__':
    main()