#!/usr/bin/python3
'''
Checks available MAME 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 and filter MAME torrents
  * Get all torrents from PleasureDome RSS
  * Get all torrents currently active in Transmission
  * Intersect the three lists to get updatable torrents
  * And for each updatable torrent:
    - remove the old torrent from Transmission,
    - rename the local directory,
    - add the new torrent

Work in progress…
  * TODO: implement some error handling

Requirements:
  * Transmission for Bitorrent
  * A PleasureDome account
  * A proper config.json file (see config.template.json)
  * Python3 with the libraries below
    - feedparser
    - transmission-clutch
  * 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 feedparser
import json
import logging
import os
import re
import requests
import time
from clutch.core import Client
from collections import defaultdict
from pprint import pformat


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

    logging.info('Opening config file: config.json')
    with open('config.json') as config_file:
        config = json.load(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:
        match = re_mame_version.match(directory)
        if match:
            torrents[match.group(2)]['local-version'] = int(match.group(1))
            torrents[match.group(2)]['local-name'] = directory
    logging.debug('Found the local torrent versions: %s', pformat(torrents))


def fetch_remote_terrents():
    """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:
        match = re_mame_version.match(post.title)
        if match:
            torrents[match.group(2)]['remote-version'] = int(match.group(1))
            torrents[match.group(2)]['remote-link'] = post.link
            torrents[match.group(2)]['remote-name'] = post.title
    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', 'transmission-id'}
        if not (
            keys_to_check.issubset(data.keys())
            and
            data['local-version'] < data['remote-version']
            and
            data['remote-link'].startswith(
                'http://www.pleasuredome.org.uk/download.php'
            )
        ):
            del torrents[torrent]
    logging.info(
        'The following torrents can be updated: %s', pformat(torrents)
    )


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

    if len(torrents) > 0:
        for torrent, data in torrents.items():
            print('Torrent {}: {} -> {}'.format(
                torrent,
                data['local-version'],
                data['remote-version']
                ))
        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/login2.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():
        match = re_mame_version.match(torrent['name'])
        if match:
            torrents[match.group(2)]['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():
        old_name = os.path.join(
            config['mame-directory'],
            torrent['local-name']
        )
        new_name = os.path.join(
            config['mame-directory'],
            torrent['remote-name']
        )

        client.torrent.remove(torrent['transmission-id'])
        os.rename(old_name, new_name)
        client.torrent.add(
            filename=torrent['remote-link'],
            download_dir=config['mame-directory'],
            cookies=cookies,
            paused=False
        )


if __name__ == '__main__':
    logging.basicConfig(
        level=logging.INFO,
        format=' %(asctime)s - %(levelname)s - %(message)s'
    )

    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)

    re_mame_version = re.compile(r'MAME 0.(\d+) (.*)')
    config = open_config_file()
    torrents = defaultdict(dict)

    client = connect_to_transmission()
    cookies = get_cookies_from_pleasuredome()

    fetch_local_torrents()
    fetch_remote_terrents()
    fetch_transmission_torrents()
    filter_updatable_torrents()
    prompt_for_update()
    update_torrents()