#!/usr/bin/python3
'''
Checks available Torrents on PleasureDome
and updates the local versions if more recent
versions are detected

Basically what it does is:
  * Get all torrents in a directory torrents
  * Get all torrents from PleasureDome RSS
  * Get all torrents currently active in Transmission
  * Intersect the first two lists to get updatable torrents
  * And for each updatable torrent:
    - remove the old torrent from Transmission (if needed),
    - rename the local directory,
    - add the new torrent

Supported Torrents:
  * MAME
  * HBMAME
  * No-Intro

Work in progress…
  * TODO: implement some error handling

Requirements:
  * Transmission for Bitorrent
  * A PleasureDome account
  * A proper PDMameUpdate.json file (see PDMameUpdate.template.json)
  * Python3 with the libraries below
    - feedparser
    - transmission-clutch
    - tabulate
  * Linux (untested on other OS, but it might work)

Notes
  * This script logs in PleasureDome to get the proper cookies.
    It seems you can also set your cookies in Transmission using
    a cookies.txt file in the .config/transmission directory
    See: https://forum.transmissionbt.com/viewtopic.php?t=7468

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!! Provided with no warranty whatsoever.    !!!
!!! Make sure you understand what the script !!!
!!! does and adapt it to your context        !!!
!!! Use with caution.                        !!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
'''
import argparse
import feedparser
import json
import logging
import os
import re
import requests
import time
import pathlib
from clutch.core import Client
from tabulate import tabulate
from collections import defaultdict
from pprint import pformat
from urllib.parse import quote


def open_config_file():
    """Reads configuration from PDMameUpdate.json file"""

    locations = (
        os.environ.get("PDMAMEUPDATE_CONF"),
        "/etc",
        os.path.expanduser("~"),
        os.curdir
    )
    for loc in locations:
        if loc is not None:
            logging.info("Searching for config file in '%s'", loc)
            config_path = loc + '/PDMameUpdate.json'
            if pathlib.Path(config_path).is_file():
                config_file_loc = config_path
                break

    if 'config_file_loc' not in locals():
        logging.error("Config file not found")
        raise FileNotFoundError("Config file not found")

    logging.info('Opening config file: '+config_file_loc)
    config_file = None
    with open(config_file_loc, 'r') as config_file:
        config = json.load(config_file)
        parameters = [
            "mame-directory",
            "pleasuredome-password",
            "pleasuredome-user",
            "torrent-directory",
            "transmission-password",
            "transmission-port",
            "transmission-user"
        ]
        for key in parameters:
            if key not in config:
                logging.error('Missing key in config file: %s', key)
                raise ValueError('Invalid config file.')
        return config


def fetch_local_torrents():
    """Fetches local torrents versions"""

    logging.info('Fetching current MAME versions')
    directories = os.listdir(config['mame-directory'])
    for directory in directories:
        for regexp in regexps:
            match = regexp.search(directory)
            if match:
                version = match.group(0)
                name = regexp.sub('#', directory)
                torrents[name]['local-version'] = version
                torrents[name]['local-name'] = directory
    logging.debug('Found the local torrent versions: %s', pformat(torrents))


def fetch_remote_torrents():
    """Fetches PleasureDome torrents versions"""

    logging.info('Opening PleasureDome RSS feed')
    d = feedparser.parse('http://www.pleasuredome.org.uk/rss.xml')
    for post in d.entries:
        for regexp in regexps:
            match = regexp.search(post.title)
            if match:
                matched_version = match.group(0)
                matched_torrent = torrents[regexp.sub('#', post.title)]
                if matched_version > matched_torrent.get('remote-version', ''):
                    matched_torrent['remote-version'] = matched_version
                    matched_torrent['remote-link'] = post.link
                    matched_torrent['remote-name'] = post.title
                else:
                    logging.info("Skipping '{}' version '{}'".format(
                        match.group(0),
                        matched_version
                    ))
    logging.debug('Found the remote torrent versions: %s', pformat(torrents))


def filter_updatable_torrents():
    """Checks if newer versions are available and prompt for update"""

    for torrent, data in list(torrents.items()):
        keys_to_check = {'local-version', 'remote-version'}
        if (
            keys_to_check.issubset(data.keys())
            and
            data['local-version'] < data['remote-version']
        ):
            check_and_rewrite_download_url(data)
        else:
            del torrents[torrent]

    logging.debug(
        'The following torrents can be updated: %s',
        [t for t in torrents.keys()]
    )


def check_and_rewrite_download_url(torrent_data):
    url_match = re.compile(
        r"https?://www.pleasuredome.org.uk/details.php\?id=(.*)"
    )
    match = url_match.match(torrent_data['remote-link'])
    if match:
        url = ("http://www.pleasuredome.org.uk/download.php"
               "?id={}&f={}.torrent&secure=no").format(
            match.group(1),
            quote('+'.join(torrent_data['remote-name'].split(' ')), safe='+')
        )
        logging.info('Changed url {} to {}'.format(
            torrent_data['remote-link'],
            url
        ))
        torrent_data['remote-link'] = url


def prompt_for_update():
    """Ask for user confirmation before updating"""

    output_header = ["Torrent", "From", "To", "Transmission ID"]
    output = []
    if len(torrents) > 0:
        for torrent, data in torrents.items():
            output.append([
                torrent,
                data['local-version'],
                data['remote-version'],
                data.get('transmission-id', 'N/A')
                ])
        print(tabulate(output, headers=output_header, tablefmt="simple"))
        print('Should I update the torrents listed above? (y/N)')
        answer = input()
        if answer.lower() != 'y':
            logging.info('Quitting: user cancelled update')
            print('Quitting…')
            exit(0)
    else:
        logging.info('Quitting: no update candidate')
        print('No update found…')
        exit(0)
    logging.info('User chose to update torrents')


def get_cookies_from_pleasuredome():
    """Connects to PleasureDome to retrieve Cookies"""

    logging.info('Logging in PleasureDome')
    data = {
        'uid': config['pleasuredome-user'],
        'pwd': config['pleasuredome-password']
    }
    r = requests.post('http://www.pleasuredome.org.uk/login3.php', data=data)
    if r.status_code == 200:
        logging.info('Connected to PleasureDome')
        logging.info('Logging out')
        requests.get('http://www.pleasuredome.org.uk/logout.php')
    else:
        logging.error(
            'Connection to PleasureDome failed with status %s',
            r.status_code
        )
        exit(1)
    return {k: r.cookies[k] for k in ('uid', 'pass')}


def connect_to_transmission():
    """Connects to Transmission and return a Client object"""

    logging.info('Connecting to Transmission Remote Control')
    return Client(
            username=config['transmission-user'],
            password=config['transmission-password'],
            port=config['transmission-port']
        )


def fetch_transmission_torrents():
    """Gets the torrents id from Transmission"""

    logging.info('Listing Transmission torrents')
    for torrent in client.list().values():
        for regexp in regexps:
            match = regexp.search(torrent['name'])
            if match:
                name = regexp.sub('#', torrent['name'])
                torrents[name]['transmission-id'] = torrent['id']
    logging.debug('Found the Transmission torrent ids: %s', pformat(torrents))


def update_torrents():
    """
        Updates torrents:
          * remove it from Transmission,
          * rename the local directory,
          * and add the new torrent
    """

    logging.info('Updating torrents')
    for torrent in torrents.values():
        logging.info('Updating torrent : %s', torrent['remote-name'])
        old_name = os.path.join(
            config['mame-directory'],
            torrent['local-name']
        )
        new_name = os.path.join(
            config['mame-directory'],
            torrent['remote-name']
        )
        new_torrent = os.path.join(
            config['torrent-directory'],
            torrent['remote-name']+'.torrent'
        )
        if 'transmission-id' in torrent:
            logging.debug('Removing from transmission : %s',torrent['transmission-id'])
            client.torrent.remove(torrent['transmission-id'])
        logging.debug('Renaming %s to %s',old_name, new_name)
        os.rename(old_name, new_name)
        logging.debug('Adding to transmission : %s', torrent['remote-link'])
        client.torrent.add(
            filename=torrent['remote-link'],
            download_dir=config['mame-directory'],
            cookies=cookies,
            paused=False
        )
        if args.keep:
            logging.debug('Downloading torrent : %s', new_torrent)
            t = requests.get(torrent['remote-link'], verify=False, cookies=cookies)
            open(new_torrent, 'wb').write(t.content)


if __name__ == '__main__':
    logging.basicConfig(
        level=logging.WARNING,
        format=' %(asctime)s - %(levelname)s - %(message)s'
    )
    parser = argparse.ArgumentParser(
        description='Update PleasureDome MAME Torrents'
    )
    parser.add_argument(
        '-l', '--log',
        action='store_true',
        help='Display more log messages'
    )
    parser.add_argument(
        '-d', '--debug',
        action='store_true',
        help='Display debugging messages'
    )
    parser.add_argument(
        '-k', '--keep',
        action='store_true',
        help='Keep torrent files localy'
    )
    parser.add_argument(
        '-c', '--countdown',
        action='store_true',
        help='Start with a 5 second countdown'
    )
    args = parser.parse_args()
    if args.log:
        logging.getLogger().setLevel(logging.INFO)
    if args.debug:
        logging.getLogger().setLevel(logging.DEBUG)
    if args.countdown:
        print('PDMameUpdate is about to start')
        # Useful if you run this script when your machine boots
        for i in range(5, 0, -1):
            print('{}\r'.format(i), end=''),
            time.sleep(1)

    regexps = [
        re.compile(r'(?<=MAME )[\d.]+'),
        re.compile(r'(?<=HBMAME )[\d.]+'),
        re.compile(r'(?<=No-Intro \()[\d-]+')
    ]
    config = open_config_file()
    torrents = defaultdict(dict)

    client = connect_to_transmission()
    cookies = get_cookies_from_pleasuredome()

    fetch_local_torrents()
    fetch_remote_torrents()
    fetch_transmission_torrents()
    filter_updatable_torrents()
    prompt_for_update()
    update_torrents()