text: ###
  # Copyright (c) 2002-2004, Jeremiah Fincher
  # Copyright (c) 2008-2010, James McCoy
  # Copyright (c) 2014, Valentin Lorentz
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are met:
  #
  #   * Redistributions of source code must retain the above copyright notice,
  #     this list of conditions, and the following disclaimer.
  #   * Redistributions in binary form must reproduce the above copyright notice,
  #     this list of conditions, and the following disclaimer in the
  #     documentation and/or other materials provided with the distribution.
  #   * Neither the name of the author of this software nor the name of
  #     contributors to this software may be used to endorse or promote products
  #     derived from this software without specific prior written consent.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  ###
  
  import re
  import os
  import sys
  import json
  import time
  import types
  import string
  import socket
  import threading
  import feedparser
  
  import supybot.conf as conf
  import supybot.utils as utils
  import supybot.world as world
  from supybot.commands import *
  import supybot.utils.minisix as minisix
  import supybot.ircmsgs as ircmsgs
  import supybot.ircutils as ircutils
  import supybot.registry as registry
  import supybot.callbacks as callbacks
  from supybot.i18n import PluginInternationalization, internationalizeDocstring
  _ = PluginInternationalization('RSS')
  
  if world.testing:
      INIT_DELAY = 1
  else:
      INIT_DELAY = 10
  
  if minisix.PY2:
      from urllib2 import ProxyHandler
  else:
      from urllib.request import ProxyHandler
  
  from .config import register_feed_config
  
  def get_feedName(irc, msg, args, state):
      if irc.isChannel(args[0]):
          state.errorInvalid('feed name', args[0], 'must not be channel names.')
      if not registry.isValidRegistryName(args[0]):
          state.errorInvalid('feed name', args[0],
                             'Feed names must not include spaces.')
      if "." in args[0]:
          state.errorInvalid('feed name', args[0],
                             'Feed names must not include dots.')
      state.args.append(callbacks.canonicalName(args.pop(0)))
  addConverter('feedName', get_feedName)
  
  announced_headlines_filename = \
          conf.supybot.directories.data.dirize('RSS_announced.flat')
  
  def only_one_at_once(f):
      lock = [False]
      def newf(*args, **kwargs):
          if lock[0]:
              return
          lock[0] = True
          try:
              f(*args, **kwargs)
          finally:
              lock[0] = False
      return newf
  
  def get_entry_id(entry):
      # in order, try elements to use as unique identifier.
      # http://validator.w3.org/feed/docs/rss2.html#hrelementsOfLtitemgt
      id_elements = ('id', 'link', 'title', 'description')
      for id_element in id_elements:
          try:
              return getattr(entry, id_element)
          except AttributeError:
              pass
      raise ValueError('Feed entry is missing both title and description')
  
  class InvalidFeedUrl(ValueError):
      pass
  
  class Feed:
      __slots__ = ('url', 'name', 'data', 'last_update', 'entries',
              'etag', 'modified', 'initial',
              'lock', 'announced_entries', 'last_exception')
      def __init__(self, name, url, initial,
              plugin_is_loading=False, announced=None):
          assert name, name
          if not url:
              url = name
          if not utils.web.httpUrlRe.match(url):
              raise InvalidFeedUrl(url)
          self.name = name
          self.url = url
          self.initial = initial
          self.data = None
          # We don't want to fetch feeds right after the plugin is
          # loaded (the bot could be starting, and thus already busy)
          self.last_update = 0
          self.entries = []
          self.etag = None
          self.modified = None
          self.lock = threading.Lock()
          self.announced_entries = announced or \
                  utils.structures.TruncatableSet()
          self.last_exception = None
  
      def __repr__(self):
          return 'Feed(%r, %r, %r, <bool>, %r)' % \
                  (self.name, self.url, self.initial, self.announced_entries)
  
      def get_command(self, plugin):
          docstring = format(_("""[<number of headlines>]
  
          Reports the titles for %s at the RSS feed %u.  If
          <number of headlines> is given, returns only that many headlines.
          RSS feeds are only looked up every supybot.plugins.RSS.waitPeriod
          seconds, which defaults to 1800 (30 minutes) since that's what most
          websites prefer."""), self.name, self.url)
          def f(self2, irc, msg, args):
              args.insert(0, self.name)
              self2.rss(irc, msg, args)
          f = utils.python.changeFunctionName(f, self.name, docstring)
          f = types.MethodType(f, plugin)
          return f
  
  _sort_parameters = {
          'oldestFirst':   (('published_parsed', 'updated_parsed'), False),
          'newestFirst':   (('published_parsed', 'updated_parsed'), True),
          'outdatedFirst': (('updated_parsed', 'published_parsed'), False),
          'updatedFirst':  (('updated_parsed', 'published_parsed'), True),
          }
  def _sort_arguments(order):
      (fields, reverse) = _sort_parameters[order]
      def key(entry):
          for field in fields:
              if field in entry:
                  return entry[field]
          raise KeyError('No date field in entry.')
      return (key, reverse)
  
  def sort_feed_items(items, order):
      """Return feed items, sorted according to sortFeedItems."""
      if order == 'asInFeed':
          return items
      (key, reverse) = _sort_arguments(order)
      try:
          sitems = sorted(items, key=key, reverse=reverse)
      except KeyError:
          # feedparser normalizes required timestamp fields in ATOM and RSS
          # to the "published"/"updated" fields. Feeds missing it are unsortable by date.
          return items
      return sitems
  
  def load_announces_db(fd):
      return dict((name, utils.structures.TruncatableSet(entries))
                  for (name, entries) in json.load(fd).items())
  def save_announces_db(db, fd):
      json.dump(dict((name, list(entries)) for (name, entries) in db), fd)
  
  
  class RSS(callbacks.Plugin):
      """
      This plugin is useful both for announcing updates to RSS feeds in a
      channel, and for retrieving the headlines of RSS feeds via command.  Use
      the "add" command to add feeds to this plugin, and use the "announce"
      command to determine what feeds should be announced in a given channel.
  
      Basic usage
      ^^^^^^^^^^^
  
      1. Add a feed using
         ``@rss add limnoria https://github.com/ProgVal/Limnoria/tags.atom``.
  
         * This is RSS feed of Limnoria's stable releases.
         * You can now check the latest news from the feed with ``@limnoria``.
  
      2. To have new news automatically announced on the channel, use
         ``@rss announce add Limnoria``.
  
      To add another feed, simply replace limnoria and the address using name
      of the feed and address of the feed. For example, YLE News:
  
      1. ``@rss add yle http://yle.fi/uutiset/rss/uutiset.rss?osasto=news``
      2. ``@rss announce add yle``
  
      News on their own lines
      ^^^^^^^^^^^^^^^^^^^^^^^
  
      If you want the feed topics to be on their own lines instead of being separated by
      the separator which you have configured you can set `reply.onetoone` to False.
  
      Please first read the help for that configuration variable
  
      ``@config help reply.onetoone``
  
      and understand what it says and then you can do
  
      ``@config reply.onetoone False``
  
      """
      threaded = True
      def __init__(self, irc):
          self.__parent = super(RSS, self)
          self.__parent.__init__(irc)
  
          if world.starting:
              self._init_time = time.time() # To delay loading the feeds
          else:
              self._init_time = 0
  
          # Scheme: {name: url}
          self.feed_names = callbacks.CanonicalNameDict()
          # Scheme: {url: feed}
          self.feeds = {}
          if os.path.isfile(announced_headlines_filename):
              with open(announced_headlines_filename) as fd:
                  announced = load_announces_db(fd)
          else:
              announced = {}
          for name in self.registryValue('feeds'):
              try:
                  url = self.registryValue(registry.join(['feeds', name]))
              except registry.NonExistentRegistryEntry:
                  self.log.warning('%s is not a registered feed, removing.',name)
                  continue
              try:
                  self.register_feed(name, url, True, True, announced.get(name, []))
              except InvalidFeedUrl:
                  self.log.error('%s is not a valid feed, removing.', name)
                  continue
          world.flushers.append(self._flush)
  
      def die(self):
          self._flush()
          world.flushers.remove(self._flush)
          self.__parent.die()
  
      def _flush(self):
          l = [(f.name, f.announced_entries) for f in self.feeds.values()]
          with utils.file.AtomicFile(announced_headlines_filename, 'w',
                                     backupDir='/dev/null') as fd:
              save_announces_db(l, fd)
  
  
      ##################
      # Feed registering
  
      def assert_feed_does_not_exist(self, name, url=None):
          if self.isCommandMethod(name):
              s = format(_('I already have a command in this plugin named %s.'),
                      name)
              raise callbacks.Error(s)
          if url:
              feed = self.feeds.get(url)
              if feed and feed.name != feed.url:
                  s = format(_('I already have a feed with that URL named %s.'),
                          feed.name)
                  raise callbacks.Error(s)
  
      def register_feed(self, name, url, initial,
              plugin_is_loading, announced=None):
          self.feed_names[name] = url
          self.feeds[url] = Feed(name, url, initial,
                  plugin_is_loading, announced)
  
      def remove_feed(self, name_or_url):
          self.feed_names.pop(name_or_url, None)
          while True:
              try:
                  conf.supybot.plugins.RSS.feeds().remove(name_or_url)
              except KeyError:
                  break
          try:
              conf.supybot.plugins.RSS.feeds.unregister(name_or_url)
          except (KeyError, registry.NonExistentRegistryEntry):
              pass
  
      ##################
      # Methods handling
  
      def isCommandMethod(self, name):
          if not self.__parent.isCommandMethod(name):
              return bool(self.get_feed(name))
          else:
              return True
  
      def listCommands(self):
          return self.__parent.listCommands(self.feed_names.keys())
  
      def getCommandMethod(self, command):
          try:
              return self.__parent.getCommandMethod(command)
          except AttributeError:
              return self.get_feed(command[0]).get_command(self)
  
      def __call__(self, irc, msg):
          self.__parent.__call__(irc, msg)
          threading.Thread(target=self.update_feeds).start()
  
  
      ##################
      # Status accessors
  
      def get_feed(self, name):
          return self.feeds.get(self.feed_names.get(name, name), None)
  
      def is_expired(self, feed):
          assert feed
          period = self.registryValue('waitPeriod')
          if feed.name != feed.url: # Named feed
              specific_period = self.registryValue('feeds.%s.waitPeriod' % feed.name)
              if specific_period:
                  period = specific_period
          event_horizon = time.time() - period
          return feed.last_update < event_horizon
  
      ###############
      # Feed fetching
  
      def update_feed(self, feed):
          handlers = []
          if utils.web.proxy():
              handlers.append(ProxyHandler(
                  {'http': utils.force(utils.web.proxy())}))
              handlers.append(ProxyHandler(
                  {'https': utils.force(utils.web.proxy())}))
          with feed.lock:
              d = feedparser.parse(feed.url, etag=feed.etag,
                      modified=feed.modified, handlers=handlers)
              if 'status' not in d or d.status != 304: # Not modified
                  if 'etag' in d:
                      feed.etag = d.etag
                  if 'modified' in d:
                      feed.modified = d.modified
                  feed.data = d.feed
                  feed.entries = d.entries
                  feed.last_update = time.time()
                  # feedparser will store soft errors in bozo_exception and set
                  # the "bozo" bit to 1 on supported platforms:
                  # https://pythonhosted.org/feedparser/bozo.html
                  # If this error caused us to e.g. not get any entries at all,
                  # it may be helpful to show it as well.
                  if getattr(d, 'bozo', 0) and hasattr(d, 'bozo_exception'):
                      feed.last_exception = d.bozo_exception
                  else:
                      feed.last_exception = None
  
              (initial, feed.initial) = (feed.initial, False)
          self.announce_feed(feed, initial)
  
      def update_feed_if_needed(self, feed):
          if self.is_expired(feed) and \
                  self._init_time + INIT_DELAY < time.time():
              self.update_feed(feed)
  
      @only_one_at_once
      def update_feeds(self):
          announced_feeds = {}
          for irc in world.ircs:
              for channel in irc.state.channels:
                  channel_feed_names = self.registryValue(
                      'announce', channel, irc.network)
                  for name in channel_feed_names:
                      announced_feeds[name] = (channel, irc.network)
          for (name, (channel, network)) in announced_feeds.items():
              feed = self.get_feed(name)
              if not feed:
                  self.log.warning(
                      'Feed %s is announced in %s@%s, but does not exist. '
                      'Use "rss announce remove %s %s" to remove it from '
                      'announcements.',
                      name, channel, network, channel, name)
                  continue
              self.update_feed_if_needed(feed)
  
      def get_new_entries(self, feed):
          with feed.lock:
              entries = feed.entries
              new_entries = [entry for entry in entries
                      if get_entry_id(entry) not in feed.announced_entries]
              if not new_entries:
                  return []
              feed.announced_entries |= set(get_entry_id(entry) for entry in new_entries)
              # We keep a little more because we don't want to re-announce
              # oldest entries if one of the newest gets removed.
              feed.announced_entries.truncate(10*len(entries))
          return new_entries
  
      def announce_feed(self, feed, initial):
          new_entries = self.get_new_entries(feed)
  
          order = self.registryValue('sortFeedItems')
          new_entries = sort_feed_items(new_entries, 'newestFirst')
          for irc in world.ircs:
              for channel in irc.state.channels:
                  # Old bots have it set in plugins.RSS.announce.#channel,
                  # new bots set it in plugins.RSS.announce.:network.#channel,
                  # so we want to read from both.
                  channel_feeds = self.registryValue('announce', channel) \
                      | self.registryValue('announce', channel, irc.network)
                  if feed.name not in channel_feeds:
                      continue
                  if initial:
                      max_entries = self.registryValue(
                          'initialAnnounceHeadlines', channel, irc.network)
                  else:
                      max_entries = self.registryValue(
                          'maximumAnnounceHeadlines', channel, irc.network)
                  announced_entries = new_entries[0:max_entries]
                  announced_entries = sort_feed_items(announced_entries, order)
                  for entry in announced_entries:
                      self.announce_entry(irc, channel, feed, entry)
  
  
      #################
      # Entry rendering
  
      def should_send_entry(self, network, channel, entry):
          whitelist = self.registryValue('keywordWhitelist', channel, network)
          blacklist = self.registryValue('keywordBlacklist', channel, network)
  
          # fix shadowing by "from supybot.commands import *"
          try:
              all = __builtins__.all
              any = __builtins__.any
          except AttributeError:
              all = __builtins__['all']
              any = __builtins__['any']
  
          title = getattr(entry, 'title', '')
          description = getattr(entry, 'description', '')
  
          if whitelist:
              if all(kw not in title and kw not in description
                     for kw in whitelist):
                  return False
          if blacklist:
              if any(kw in title or kw in description
                     for kw in blacklist):
                  return False
          return True
  
      _normalize_entry = utils.str.multipleReplacer(
              {'\r': ' ', '\n': ' ', '\x00': ''})
      def format_entry(self, network, channel, feed, entry, is_announce):
          key_name = 'announceFormat' if is_announce else 'format'
          if feed.name in self.registryValue('feeds'):
              specific_key_name = registry.join(['feeds', feed.name, key_name])
              template = self.registryValue(specific_key_name,
                                            channel, network) or \
                      self.registryValue(key_name, channel, network)
          else:
              template = self.registryValue(key_name, channel, network)
          date = entry.get('published_parsed')
          date = utils.str.timestamp(date)
          s = string.Template(template).substitute(
                  entry,
                  feed_name=feed.name,
                  date=date)
          return self._normalize_entry(s)
  
      def announce_entry(self, irc, channel, feed, entry):
          if self.should_send_entry(irc.network, channel, entry):
              s = self.format_entry(irc.network, channel, feed, entry, True)
              if self.registryValue('notice', channel, irc.network):
                  m = ircmsgs.notice(channel, s)
              else:
                  m = ircmsgs.privmsg(channel, s)
              irc.queueMsg(m)
  
  
      ##########
      # Commands
  
      @internationalizeDocstring
      def add(self, irc, msg, args, name, url):
          """<name> <url>
  
          Adds a command to this plugin that will look up the RSS feed at the
          given URL.
          """
          self.assert_feed_does_not_exist(name, url)
          register_feed_config(name, url)
          self.register_feed(name, url, True, False)
          irc.replySuccess()
      add = wrap(add, ['feedName', 'url'])
  
      @internationalizeDocstring
      def remove(self, irc, msg, args, name):
          """<name>
  
          Removes the command for looking up RSS feeds at <name> from
          this plugin.
          """
          feed = self.get_feed(name)
          if not feed:
              irc.error(_('That\'s not a valid RSS feed command name.'))
              return
  
          # If the feed was first created "anonymously", eg. with
          # `@rss announce add http://example.org/rss`, then as a named feed
          # with `@rss add example http://example.org/rss`,
          # `self.get_feed(name)` above gets only one of them; so let's
          # remove the aliased name or URL from the feed names too,
          # or we would have a dangling entry here.
          self.remove_feed(feed.url)
          self.remove_feed(name)
          assert self.get_feed(name) is None
  
          irc.replySuccess()
      remove = wrap(remove, ['feedName'])
  
      class announce(callbacks.Commands):
          @internationalizeDocstring
          def list(self, irc, msg, args, channel):
              """[<channel>]
  
              Returns the list of feeds announced in <channel>.  <channel> is
              only necessary if the message isn't sent in the channel itself.
              """
              announce = conf.supybot.plugins.RSS.announce
              channel_feeds = announce.getSpecific(channel=channel) \
                  | announce.getSpecific(channel=channel, network=irc.network)
              feeds = format('%L', set(channel_feeds)) # set() to deduplicate
              irc.reply(feeds or _('I am currently not announcing any feeds.'))
          list = wrap(list, ['channel',])
  
          @internationalizeDocstring
          def add(self, irc, msg, args, channel, feeds):
              """[<channel>] <name|url> [<name|url> ...]
  
              Adds the list of feeds to the current list of announced feeds in
              <channel>.  Valid feeds include the names of registered feeds as
              well as URLs for RSS feeds.  <channel> is only necessary if the
              message isn't sent in the channel itself.
              """
              plugin = irc.getCallback('RSS')
              invalid_feeds = [x for x in feeds if not plugin.get_feed(x)
                               and not utils.web.urlRe.match(x)]
              if invalid_feeds:
                  irc.error(format(_('These feeds are unknown: %L'),
                      invalid_feeds), Raise=True)
              announce = conf.supybot.plugins.RSS.announce
              S = announce.getSpecific(channel=channel, network=irc.network)()
              for name in feeds:
                  S.add(name)
              announce.getSpecific(channel=channel, network=irc.network).setValue(S)
              irc.replySuccess()
              for name in feeds:
                  feed = plugin.get_feed(name)
                  if not feed:
                      register_feed_config(name, name)
                      plugin.register_feed(name, name, True, False)
                      feed = plugin.get_feed(name)
                  plugin.announce_feed(feed, True)
          add = wrap(add, [('checkChannelCapability', 'op'),
                           many(first('url', 'feedName'))])
  
          @internationalizeDocstring
          def remove(self, irc, msg, args, channel, feeds):
              """[<channel>] <name|url> [<name|url> ...]
  
              Removes the list of feeds from the current list of announced feeds
              in <channel>.  Valid feeds include the names of registered feeds as
              well as URLs for RSS feeds.  <channel> is only necessary if the
              message isn't sent in the channel itself.
              """
              announce = conf.supybot.plugins.RSS.announce
  
              def remove_from_var(var):
                  S = var()
                  for feed in feeds:
                      S.discard(feed)
                  var.setValue(S)
  
              remove_from_var(announce.get(channel))
              remove_from_var(announce.getSpecific(
                  channel=channel, network=irc.network))
  
              irc.replySuccess()
          remove = wrap(remove, [('checkChannelCapability', 'op'),
                                 many(first('url', 'feedName'))])
  
          @internationalizeDocstring
          def channels(self, irc, msg, args, feed):
              """<name|url>
  
              Returns a list of channels that the given feed name or URL is being
              announced to.
              """
              plugin = irc.getCallback('RSS')
              if not plugin.get_feed(feed):
                  irc.error(_("Unknown feed %s" % feed), Raise=True)
  
              channels = []
              for ircnet in world.ircs:
                  for channel in ircnet.state.channels:
                      if feed in plugin.registryValue('announce', channel, ircnet.network):
                          channels.append(ircnet.network + channel)
  
              if channels:
                  irc.reply(format("%s is announced to %L.", feed, channels))
              else:
                  irc.reply("%s is not announced to any channels." % feed)
  
          channels = wrap(channels, ['feedName'])
  
      @internationalizeDocstring
      def rss(self, irc, msg, args, url, n):
          """<name|url> [<number of headlines>]
  
          Gets the title components of the given RSS feed.
          If <number of headlines> is given, return only that many headlines.
          """
          self.log.debug('Fetching %u', url)
          try:
              feed = self.get_feed(url)
              if not feed:
                  feed = Feed(url, url, True)
          except InvalidFeedUrl:
              irc.error('%s is not a valid feed URL or name.' % url, Raise=True)
          channel = msg.channel
          self.update_feed_if_needed(feed)
          entries = feed.entries
          if not entries:
              s = _('Couldn\'t get RSS feed.')
              # If we got a soft parsing exception on our last run, show the error.
              if feed.last_exception is not None:
                  s += _(' Parser error: ')
                  s += str(feed.last_exception)
              irc.error(s)
              return
          n = n or self.registryValue('defaultNumberOfHeadlines', channel, irc.network)
          entries = list(filter(lambda e:self.should_send_entry(irc.network, channel, e),
                                feed.entries))
          entries = entries[:n]
          headlines = map(lambda e:self.format_entry(irc.network, channel, feed, e, False),
                          entries)
          sep = self.registryValue('headlineSeparator', channel, irc.network)
          irc.replies(headlines, joiner=sep)
      rss = wrap(rss, [first('url', 'feedName'), additional('int')])
  
      @internationalizeDocstring
      def info(self, irc, msg, args, url):
          """<url|feed>
  
          Returns information from the given RSS feed, namely the title,
          URL, description, and last update date, if available.
          """
          try:
              url = self.registryValue('feeds.%s' % url)
          except registry.NonExistentRegistryEntry:
              pass
          feed = self.get_feed(url)
          if not feed:
              feed = Feed(url, url, True)
          self.update_feed_if_needed(feed)
          info = feed.data
          if not info:
              irc.error(_('I couldn\'t retrieve that RSS feed.'))
              return
          # check the 'modified_parsed' key, if it's there, convert it here first
          if 'modified' in info:
              seconds = time.mktime(info['modified_parsed'])
              now = time.mktime(time.gmtime())
              when = utils.timeElapsed(now - seconds) + ' ago'
          else:
              when = _('time unavailable')
          title = info.get('title', _('unavailable'))
          desc = info.get('description', _('unavailable'))
          link = info.get('link', _('unavailable'))
          # The rest of the entries are all available in the channel key
          response = format(_('Title: %s;  URL: %u;  '
                            'Description: %s;  Last updated: %s.'),
                            title, link, desc, when)
          irc.reply(utils.str.normalizeWhitespace(response))
      info = wrap(info, [first('url', 'feedName')])
  RSS = internationalizeDocstring(RSS)
  
  Class = RSS
  
  # vim:set shiftwidth=4 softtabstop=4 expandtab textwidth=79:
  