#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import html
import logging
import re
import sys
from configparser import ConfigParser
from json import loads
from urllib.parse import urlparse

import feedparser
import redis
import telegram
from telegram.ext import CommandHandler, Updater
from telegram.ext.dispatcher import run_async

import utils

# Logging
logging.basicConfig(
    format="%(asctime)s - %(levelname)s: %(message)s",
    datefmt="%d.%m.%Y %H:%M:%S",
    level=logging.INFO
)
logger = logging.getLogger(__name__)

# Bot configuration
config = ConfigParser()
try:
    config.read_file(open('config.ini'))
except FileNotFoundError:
    logger.critical('Config.ini nicht gefunden')
    sys.exit(1)

# Bot token
try:
    bot_token = config['DEFAULT']['token']
except KeyError:
    logger.error('Kein Bot-Token gesetzt, bitte config.ini prüfen')
    sys.exit(1)
if not bot_token:
    logger.error('Kein Bot-Token gesetzt, bitte config.ini prüfen')
    sys.exit(1)

# Admins
try:
    admins = loads(config["ADMIN"]["id"])
except KeyError:
    logger.error('Keine Admin-IDs gesetzt, bitte config.ini prüfen.')
    sys.exit(1)
if not admins:
    logger.error('Keine Admin-IDs gesetzt, bitte config.ini prüfen.')
    sys.exit(1)

for admin in admins:
    if not isinstance(admin, int):
        logger.error('Admin-IDs müssen Integer sein.')
        sys.exit(1)

# Redis
redis_conf = config['REDIS']
redis_db = redis_conf.get('db', 0)
redis_host = redis_conf.get('host', '127.0.0.1')
redis_port = redis_conf.get('port', 6379)
redis_socket = redis_conf.get('socket_path')
if redis_socket:
    r = redis.Redis(unix_socket_path=redis_socket, db=int(redis_db), decode_responses=True)
else:
    r = redis.Redis(host=redis_host, port=int(redis_port), db=int(redis_db), decode_responses=True)

if not r.ping():
    logging.getLogger("Redis").critical("Redis-Verbindungsfehler, config.ini prüfen")
    sys.exit(1)

feed_hash = 'pythonbot:rss:{0}'


@run_async
def start(bot, update):
    if not utils.can_use_bot(update):
        return
    update.message.reply_text(
        text='<b>Willkommen beim RSS-Bot!</b>\nSende /help, um zu starten.',
        parse_mode=telegram.ParseMode.HTML
    )


@run_async
def help_text(bot, update):
    if not utils.can_use_bot(update):
        return
    update.message.reply_text(
        text='<b>/rss</b> <i>[Chat]</i>: Abonnierte Feeds anzeigen\n'
             '<b>/sub</b> <i>Feed-URL</i> <i>[Chat]</i>: Feed abonnieren\n'
             '<b>/del</b> <i>n</i> <i>[Chat]</i>: Feed löschen',
        parse_mode=telegram.ParseMode.HTML
    )


@run_async
def list_feeds(bot, update, args):
    if not utils.can_use_bot(update):
        return
    if args:
        chat_name = args[0]
        try:
            resp = bot.getChat(chat_name)
        except telegram.error.BadRequest:
            update.message.reply_text('❌ Dieser Kanal existiert nicht.')
            return
        chat_id = str(resp.id)
        chat_title = resp.title
    else:
        chat_id = str(update.message.chat.id)
        if update.message.chat.type == 'private':
            chat_title = update.message.chat.first_name
        else:
            chat_title = update.message.chat.title

    subs = r.smembers(feed_hash.format(chat_id))
    if not subs:
        text = '❌ Keine Feeds abonniert.'
    else:
        text = '<b>' + html.escape(chat_title) + '</b> hat abonniert:\n'
        for n, feed in enumerate(subs):
            text += '<b>' + str(n + 1) + ')</b> ' + feed + '\n'

    update.message.reply_text(
        text=text,
        parse_mode=telegram.ParseMode.HTML
    )


@run_async
def subscribe(bot, update, args):
    if not utils.can_use_bot(update):
        return
    if not args:
        update.message.reply_text('❌ Keine Feed-URL angegeben.')
        return
    feed_url = args[0]
    if not re.match("^http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&~+]|[!*(),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+$", feed_url):
        update.message.reply_text('❌ Das ist keine URL.')
        return

    # Get Chat ID from name if given
    if len(args) > 1:
        chat_name = args[1]
        try:
            resp = bot.getChat(chat_name)
        except telegram.error.BadRequest:
            update.message.reply_text('❌ Dieser Kanal existiert nicht.')
            return
        chat_id = str(resp.id)
        resp = bot.getChatMember(chat_id, bot.id)
        if resp.status != 'administrator':
            update.message.reply_text('❌ Bot ist kein Administrator in diesem Kanal.')
            return
    else:
        chat_id = str(update.message.chat.id)

    bot.sendChatAction(update.message.chat.id, action=telegram.ChatAction.TYPING)
    data = feedparser.parse(feed_url)
    if 'link' not in data.feed:
        update.message.reply_text('❌ Kein gültiger Feed.')
        return
    feed_url = data.href  # Follow all redirects
    if r.sismember(feed_hash.format(chat_id), feed_url):
        update.message.reply_text('✅ Dieser Feed wurde bereits abonniert.')
        return

    if 'title' not in data.feed:
        feed_title = feed_url
    else:
        feed_title = html.escape(data.feed['title'])

    # Save the last entry in Redis, if it doesn't exist
    if data.entries:
        last_entry_hash = feed_hash.format(feed_url + ':last_entry')
        if not r.exists(last_entry_hash):
            if 'id' not in data.entries[0]:
                last_entry = data.entries[0]['link']
            else:
                last_entry = data.entries[0]['id']
            r.set(last_entry_hash, last_entry)

    r.sadd(feed_hash.format(feed_url + ':subs'), chat_id)
    r.sadd(feed_hash.format(chat_id), feed_url)
    update.message.reply_text(
        text='✅ <b>' + feed_title + '</b> hinzugefügt!',
        parse_mode=telegram.ParseMode.HTML
    )


@run_async
def unsubscribe(bot, update, args):
    if not utils.can_use_bot(update):
        return
    if not args:
        update.message.reply_text('❌ Keine Nummer angegeben.')
        return

    # Get Chat ID from name if given
    if len(args) > 1:
        chat_name = args[1]
        try:
            resp = bot.getChat(chat_name)
        except telegram.error.BadRequest:
            update.message.reply_text('❌ Dieser Kanal existiert nicht.')
            return
        chat_id = str(resp.id)
    else:
        chat_id = str(update.message.chat.id)

    try:
        n = int(args[0])
    except ValueError:
        update.message.reply_text('❌ Keine Nummer angegeben.')
        return

    chat_hash = feed_hash.format(chat_id)
    subs = r.smembers(chat_hash)
    if n < 1:
        update.message.reply_text('❌ Nummer muss größer als 0 sein!')
        return
    elif n > len(subs):
        update.message.reply_text('❌ Feed-ID zu hoch.')
        return

    feed_url = list(subs)[n - 1]
    sub_hash = feed_hash.format(feed_url + ':subs')
    r.srem(chat_hash, feed_url)
    r.srem(sub_hash, chat_id)
    if not r.smembers(sub_hash):  # no one subscribed, remove it
        r.delete(feed_hash.format(feed_url + ':last_entry'))

    update.message.reply_text(
        text='✅ <b>' + feed_url + '</b> entfernt.',
        parse_mode=telegram.ParseMode.HTML
    )


@run_async
def check_feed(bot, key):
    feed_url = re.match('^' + feed_hash.format('(.+):subs$'), key).group(1)
    logger.info(feed_url)
    data = feedparser.parse(feed_url)
    if 'link' not in data.feed:
        if 'status' in data and data["status"] != 200:
            logger.warning('Kein gültiger Feed, HTTP-Status-Code ' + str(data["status"]))
        else:
            logger.warning('Kein gültiger Feed: ' + str(data.bozo_exception))
        return None
    if 'title' not in data.feed:
        feed_title = data.feed['link']
    else:
        feed_title = data.feed['title']
    last_entry_hash = feed_hash.format(feed_url + ':last_entry')
    last_entry = r.get(last_entry_hash)
    new_entries = utils.get_new_entries(data.entries, last_entry)
    for entry in reversed(new_entries):
        if 'title' not in entry:
            post_title = 'Kein Titel'
        else:
            post_title = utils.remove_html_tags(entry['title']).strip()
            post_title = post_title.replace('<', '&lt;').replace('>', '&gt;')
        if 'link' not in entry:
            post_link = data.link
            link_name = post_link
        else:
            post_link = entry.link
            feedproxy = re.search('^https?://feedproxy\.google\.com/~r/(.+?)/.*', post_link)  # feedproxy.google.com
            if feedproxy:
                link_name = feedproxy.group(1)
            else:
                link_name = urlparse(post_link).netloc
        link_name = re.sub('^www\d?\.', '', link_name)  # remove www.
        if 'content' in entry:
            content = utils.get_content(entry.content[0]['value'])
        elif 'summary' in entry:
            content = utils.get_content(entry.summary)
        else:
            content = ''
        text = '<b>{post_title}</b>\n<i>{feed_title}</i>\n{content}'.format(
            post_title=post_title,
            feed_title=feed_title,
            content=content
        )
        text += '\n<a href="{post_link}">Auf {link_name} weiterlesen</a>\n'.format(
            post_link=post_link,
            link_name=link_name
        )
        for member in r.smembers(key):
            try:
                bot.sendMessage(
                    chat_id=member,
                    text=text,
                    parse_mode=telegram.ParseMode.HTML,
                    disable_web_page_preview=True
                )
            except telegram.error.Unauthorized:
                logger.warning('Chat ' + member + ' existiert nicht mehr, wird gelöscht.')
                r.srem(key, member)
                r.delete(feed_hash.format(member))
            except telegram.error.ChatMigrated as new_chat:
                new_chat_id = new_chat.new_chat_id
                logger.info('Chat migriert: ' + member + ' -> ' + str(new_chat_id))
                r.srem(key, member)
                r.sadd(key, new_chat_id)
                r.rename(feed_hash.format(member), feed_hash.format(new_chat_id))
                bot.sendMessage(
                    chat_id=member,
                    text=text,
                    parse_mode=telegram.ParseMode.HTML,
                    disable_web_page_preview=True
                )
            except telegram.error.TimedOut:
                pass
            except telegram.error.BadRequest as exception:
                logger.error(exception)

    if not r.exists(key):
        r.delete(last_entry_hash)
        return

    # Set the new last entry if there are any
    if new_entries:
        if 'id' not in new_entries[0]:
            new_last_entry = new_entries[0].link
        else:
            new_last_entry = new_entries[0].id
        r.set(last_entry_hash, new_last_entry)


@run_async
def run_job(bot, job=None):
    logger.info('================================')
    keys = r.keys(feed_hash.format('*:subs'))
    for key in keys:
        check_feed(bot, key)


def onerror(bot, update, error):
    logger.error(error)


# Main function
def main():
    # Setup the updater and show bot info
    updater = Updater(token=bot_token)
    try:
        bot_info = updater.bot.getMe()
    except telegram.error.Unauthorized:
        logger.error('Anmeldung nicht möglich, Bot-Token falsch?')
        sys.exit(1)

    logger.info('Starte ' + bot_info.first_name + ', AKA @' + bot_info.username + ' (' + str(bot_info.id) + ')')

    # Register Handlers
    handlers = [
        CommandHandler('start', start),
        CommandHandler('help', help_text),
        CommandHandler('rss', list_feeds, pass_args=True),
        CommandHandler('sub', subscribe, pass_args=True),
        CommandHandler('del', unsubscribe, pass_args=True),
        CommandHandler('sync', run_job)
    ]
    for handler in handlers:
        updater.dispatcher.add_handler(handler)

    # Hide "Error while getting Updates" because it's not our fault
    updater.logger.addFilter((lambda log: not log.msg.startswith('Error while getting Updates:')))

    # Fix for Python <= 3.5
    updater.dispatcher.add_error_handler(onerror)

    updater.job_queue.run_repeating(
        run_job,
        interval=60.0,
        first=2.0
    )

    # Start this thing!
    updater.start_polling(
        clean=True,
        bootstrap_retries=-1,
        allowed_updates=["message"]
    )

    # Run Bot until CTRL+C is pressed or a SIGINIT,
    # SIGTERM or SIGABRT is sent.
    updater.idle()


if __name__ == '__main__':
    main()