# -*- coding: utf-8 -*-

# Copyright (C) 2011, 2014, 2020 kaliko <kaliko@azylum.org>
# Copyright (C) 2020 Adrien Bourmault <neox@os-k.eu>

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 only.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import datetime
import threading
import time
import traceback

from urllib.error import URLError

from feedparser import parse as feed_parse

from sid.plugin import Plugin, botcmd


html_escape_table = {
        "&": "&amp;",
        '"': "&quot;",
        "'": "&apos;",
        ">": "&gt;",
        "<": "&lt;",
        }


def html_escape(text):
    """Produce entities within text."""
    return ''.join(html_escape_table.get(c, c) for c in text)


def strtm_to_dtm(struc_time):
    return datetime.datetime(*struc_time[:6])


class FeedMonitor(threading.Thread):
    def __init__(self, plugin):
        threading.Thread.__init__(self)
        self.feeds_list = plugin.FEEDS
        self.tempo = plugin.TEMPO
        self.plugin = plugin
        self.last_check = datetime.datetime.utcnow()
        self.seen = dict()
        self.thread_killed = False

    def _update_cache(self, feed, parsed):
        self.seen[feed].update({'ids': {p.id for p in parsed.entries} or {}})
        # Common HTTP caching
        if parsed.get('etag', False):
            self.seen[feed].update({'cache': {'etag': parsed.etag}})
        if parsed.get('modified', False):
            self.seen[feed].update({'cache': {'modified': parsed.modified}})

    def new_posts(self, feed):
        """Send new posts in feed"""
        self.plugin.log.debug('feed:     : "%s"', feed)
        if self.seen.get(feed) and self.seen.get(feed).get('cache'):
            parsed_feed = feed_parse(feed, **self.seen[feed]['cache'])
        else:
            if self.seen.get(feed):
                self.plugin.log.debug('No cache headers set (etag/modified)')
            parsed_feed = feed_parse(feed)
        # Cannot resolve address
        if 'status' not in parsed_feed:
            self.plugin.log.error('Error from "%s": %s.',
                                  feed, parsed_feed.bozo_exception.__repr__())
            return
        # http caching
        if parsed_feed.status == 304:
            self.plugin.log.debug('Got 304 not modified')
            return
        # unusual return http code
        if parsed_feed.status != 200:
            self.plugin.log.warning(
                'Got code %(status)d from "%(href)s" (please update).',
                parsed_feed)
            return
        if not self.seen.setdefault(feed):
            # Fills with post id when first started (prevent from posting all
            # entries at startup)
            self.seen[feed] = {'cache': None}
            self._update_cache(feed, parsed_feed)
            return
        title = '[%s]' % parsed_feed.feed.get('title', 'n/a')
        xtitle = '<strong>%s</strong>:' % html_escape(
            parsed_feed.feed.get('title', 'n/a'))
        text = [title]
        xhtml = [xtitle]

        # Detecting new post
        entries = {p.id for p in parsed_feed.entries}
        seen_ids = self.seen.get(feed).get('ids')
        new_entries = [p for p in parsed_feed.entries
                       if p.id in entries - seen_ids]
        for post in new_entries:
            self.plugin.log.info(post.title)
            body = '%(title)s ' % post
            try:
                body += "\nSummary: " + bs4.BeautifulSoup('%(summary)s' % post).select(".blockquote")[0].get_text()
            except IndexError:
                pass
            body += '\n%(link)s' % post 
            text.append(bs4.BeautifulSoup(body).get_text())
            xpost = {'title': html_escape(post.get('title', 'n/a'))}
            xpost['link'] = html_escape(post.get('link',))
            xbody = '<a href="{link}">{title}</a>'.format(**xpost)
            xhtml.append(xbody)
        # Updating self.seen, entries and cache headers
        self._update_cache(feed, parsed_feed)
        if len(text) > 1:
            self.plugin.send(self.plugin.bot.room,
                    {'mhtml': '<br />'.join(xhtml), 'mbody': '\n'.join(text)},
                    mtype='groupchat')

    def run(self):
        while not self.thread_killed:
            self.plugin.log.debug('feeds check')
            for feed in self.feeds_list:
                try:
                    self.new_posts(feed)
                except ConnectionError as err:  # Non fatal exception
                    self.plugin.log.error('connection error on %s: %s', feed, err)
                except URLError as err:  # Non fatal exception
                    self.plugin.log.error('error for "%s": %s', feed, err.reason)
                except Exception as err:  # Unknown execption, killing thread anyway
                    self.plugin.log.error('feeds thread crashed: %s', err)
                    self.plugin.log.error(''.join(traceback.format_exc()))
                    self.thread_killed = True
            self.last_check = datetime.datetime.utcnow()
            for _ in list(range(self.tempo)):
                time.sleep(1)
                if self.thread_killed:
                    return


class Feeds(Plugin):
    """
    .. note::
      Feeds plugin depends on external module: **feedparser**
    """

    TEMPO = 60
    FEEDS = [   'https://gitlab.os-k.eu/emooji-team/emooji.atom?feed_token=En-15azki1VriEgkCQHN'
        ]
    
    def __init__(self, bot):
        Plugin.__init__(self, bot)
        self.last_check = None
        self.th_mon = FeedMonitor(self)
        self.th_mon.start()

    def shutdown(self):
        self.th_mon.thread_killed = True

    @botcmd
    def feeds(self, rcv, args):
        """Monitors project related feeds.

        * ``!feeds``      : registred feeds list
        * ``!feeds last`` : last check time"""
        if 'last' in args:
            date = '{:%Y-%m-%d %H:%M} (utc)'.format(self.th_mon.last_check)
            self.reply(rcv, f'Last feeds check: {date}')
            return
        html = ['<a href="{0}">{1}</a>'.format(html_escape(u),
                                               html_escape(u[7:])
                                              ) for u in Feeds.FEEDS]
        msg = {'mbody': 'Feeds:\n' + '\n'.join(Feeds.FEEDS),
               'mhtml': 'Feeds:<br />' + '<br />'.join(html)}
        self.reply(rcv, msg)