#!/usr/bin/python3

import configparser
import gzip
import io
import os
import struct
import sys
import urllib.request
import xmlrpc.client

def file_hash(filename):
    fmt = '<q'
    bcount = struct.calcsize(fmt)
    csize = 65536

    f = open(filename, mode='rb')
    h = 0

    for i in range(csize // bcount):
        (val,) = struct.unpack(fmt, f.read(bcount))
        h = (h + val) % (2**64)
    f.seek(-csize, io.SEEK_END)
    for i in range(csize // bcount):
        (val,) = struct.unpack(fmt, f.read(bcount))
        h = (h + val) % (2**64)

    s = f.tell()
    h = (h + s) % (2**64)
    return format(h, 'x'), s

def usage():
    print('Usage: {} FILE...'.format(os.path.basename(sys.argv[0])))

def login(user='', password='', lang='en'):
    token = None
    try:
        reply = server.LogIn(user, password, lang, 'sub v0.1')
        if reply['status'] == '200 OK':
            token = reply['token']
        else:
            sys.stderr.write('Could not log in: {}\n'.format(reply['status']))
    except xmlrpc.client.ProtocolError as e:
        sys.stderr.write('Error logging in: {}\n'.format(e))
    return token

config = configparser.ConfigParser()
opt = config['options'] = {
    'username': '',
    'password': '',
    'language': 'eng'
}
config.read(os.path.expanduser('~/.subrc'))

if len(sys.argv) < 2:
    usage()
    sys.exit()

print('Downloading subtitles from opensubtitles.org...')
server = xmlrpc.client.ServerProxy('http://api.opensubtitles.org/xml-rpc')
token = login(opt['username'], opt['password'])
if token is None:
    sys.exit(1)

for filename in sys.argv[1:]:
    sub_filename = os.path.splitext(filename)[0] + '.sub'
    if os.path.exists(sub_filename):
        print('Already have ' + filename)
        continue

    h, s = file_hash(filename)
    query = {}
    query['moviehash'] = h
    query['moviebytesize'] = format(s)
    query['sublanguageid'] = opt['language']

    reply = server.SearchSubtitles(token, [query])
    if reply['status'] == '200 OK' and reply['data']:
        print('Subtitles found for ' + filename)
        results = reply['data']
        results.sort(key = lambda record: record['SubDownloadsCnt'], reverse=True)

        sub_filename = os.path.splitext(filename)[0] + '.sub'
        f = open(sub_filename, 'wb')

        url = results[0]['SubDownloadLink']
        sub_data = gzip.decompress(urllib.request.urlopen(url).read())

        f.write(sub_data)
        f.close()
    else:
        print('Subtitles NOT found for ' + filename)