#!/usr/bin/env python

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"""
Provides basic functionality for handling RSS/RDF feeds.
"""

__revision__ = "$Id$"

import plugins

import sets
import time
from itertools import imap

import rssparser

import conf
import utils
import ircmsgs
import ircutils
import privmsgs
import registry
import callbacks

def configure(onStart, afterConnect, advanced):
    from questions import expect, anything, something, yn
    onStart.append('load RSS')
    prompt = 'Would you like to add an RSS feed?'
    while yn(prompt) == 'y':
        prompt = 'Would you like to add another RSS feed?'
        name = something('What\'s the name of the website?')
        url = something('What\'s the URL of the RSS feed?')
        onStart.append('rss add %s %s' % (name, url))

class StringWithSpaceOnRight(registry.String):
    def setValue(self, v):
        if v.rstrip() == v:
            v += ' '
        registry.String.setValue(self, v)
        
conf.registerPlugin('RSS')
conf.registerChannelValue(conf.supybot.plugins.RSS, 'bold', registry.Boolean(
    True, """Determines whether the bot will bold the title of the feed when it
    announces new news."""))
conf.registerChannelValue(conf.supybot.plugins.RSS, 'headlineSeparator',
    registry.StringSurroundedBySpaces(' || ', """Determines what string is used
    to separate headlines in new feeds."""))
conf.registerChannelValue(conf.supybot.plugins.RSS, 'announcementPrefix',
    StringWithSpaceOnRight('New news from ', """Determines what prefix is
    prepended (if any) to the new news item announcements made in the
    channel."""))
conf.registerChannelValue(conf.supybot.plugins.RSS, 'announce',
    registry.SpaceSeparatedListOfStrings([], """Determines which RSS feeds
    should be announced in the channel; valid input is a list of strings
    (either registered RSS feeds or RSS feed URLs) separated by spaces."""))
conf.registerGlobalValue(conf.supybot.plugins.RSS, 'waitPeriod',
    registry.PositiveInteger(1800, """Indicates how many seconds the bot will
    wait between retrieving RSS feeds; requests made within this period will
    return cached results."""))
conf.registerGroup(conf.supybot.plugins.RSS, 'feeds')

def registerFeed(name, url):
    conf.supybot.plugins.RSS.feeds.register(name, registry.String(url, ''))
    
class RSS(callbacks.Privmsg):
    threaded = True
    def __init__(self):
        callbacks.Privmsg.__init__(self)
        self.feedNames = sets.Set()
        self.lastRequest = {}
        self.cachedFeeds = {}
        L = conf.supybot.plugins.RSS.feeds.getValues(fullNames=False)
        for (name, url) in registry._cache.iteritems():
            name = name.lower()
            if name.startswith('supybot.plugins.rss.feeds.'):
                name = rsplit(name, '.', 1)[-1]
                v = registry.String('', 'help is not needed here')
                v.set(url)
                url = v()
                self.makeFeedCommand(name, url)

    def __call__(self, irc, msg):
        callbacks.Privmsg.__call__(self, irc, msg)
        irc = callbacks.IrcObjectProxyRegexp(irc, msg)
        L = conf.supybot.plugins.RSS.announce.getValues(fullNames=False)
        for (channel, v) in L:
            feeds = v() 
            bold = self.registryValue('bold', channel)
            sep = self.registryValue('headlineSeparator', channel)
            prefix = self.registryValue('announcementPrefix', channel)
            for name in feeds:
                if self.isCommand(callbacks.canonicalName(name)):
                    url = self.getCommand(name).url
                else:
                    url = name
                try:
                    oldresults = self.cachedFeeds[url]
                    oldheadlines = self.getHeadlines(oldresults)
                except KeyError:
                    oldheadlines = []
                newresults = self.getFeed(url)
                newheadlines = self.getHeadlines(newresults)
                for headline in oldheadlines:
                    try:
                        newheadlines.remove(headline)
                    except ValueError:
                        pass
                if newheadlines:
                    pre = prefix + name
                    if bold:
                        pre = ircutils.bold(pre)
                    irc.replies(newheadlines, prefixer=pre, joiner=sep)
                
    def getFeed(self, url):
        now = time.time()
        wait = self.registryValue('waitPeriod')
        if url not in self.lastRequest or now - self.lastRequest[url] > wait:
            try:
                self.log.info('Downloading new feed from %s', url)
                results = rssparser.parse(url)
            except sgmllib.SGMLParseError:
                self.log.exception('Uncaught exception from rssparser:')
                raise callbacks.Error, 'Invalid (unparseable) RSS feed.'
            self.cachedFeeds[url] = results
            self.lastRequest[url] = now
        return self.cachedFeeds[url]

    def getHeadlines(self, feed):
        return [utils.htmlToText(d['title'].strip()) for d in feed['items']]

    def makeFeedCommand(self, name, url):
        docstring = """takes no arguments

        Reports the titles for %s at the RSS feed <%s>.  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.
        """ % (name, url)
        name = callbacks.canonicalName(name)
        if hasattr(self, name):
            s = 'I already have a command in this plugin named %s' % name
            raise callbacks.Error, s
        def f(self, irc, msg, args):
            args.insert(0, url)
            self.rss(irc, msg, args)
        f = utils.changeFunctionName(f, name, docstring)
        f.url = url # Used by __call__.
        self.feedNames.add(name)
        setattr(self.__class__, name, f)
        registerFeed(name, url)
        
    def add(self, irc, msg, args):
        """<name> <url>

        Adds a command to this plugin that will look up the RSS feed at the
        given URL.
        """
        (name, url) = privmsgs.getArgs(args, required=2)
        self.makeFeedCommand(name, url)
        irc.replySuccess()

    def remove(self, irc, msg, args):
        """<name>

        Removes the command for looking up RSS feeds at <name> from
        this plugin.
        """
        name = privmsgs.getArgs(args)
        name = callbacks.canonicalName(name)
        if name not in self.feedNames:
            irc.error('That\'s not a valid RSS feed command name.')
            return
        delattr(self.__class__, name)
        irc.replySuccess()
        
    def rss(self, irc, msg, args):
        """<url>

        Gets the title components of the given RSS feed.
        """
        url = privmsgs.getArgs(args)
        self.log.debug('Fetching %s', url)
        feed = self.getFeed(url)
        if ircutils.isChannel(msg.args[0]):
            channel = msg.args[0]
        else:
            channel = None
        headlines = self.getHeadlines(feed)
        if not headlines:
            irc.error('Couldn\'t get RSS feed')
            return
        headlines = imap(utils.htmlToText, headlines)
        sep = self.registryValue('headlineSeparator', channel)
        irc.reply(sep.join(headlines))

    def info(self, irc, msg, args):
        """<url>

        Returns information from the given RSS feed, namely the title,
        URL, description, and last update date, if available.
        """
        url = privmsgs.getArgs(args)
        feed = self.getFeed(url)
        info = feed['channel']
        if not info:
            irc.error('I couldn\'t retrieve that RSS feed.')
            return
        # check the 'modified' key, if it's there, convert it here first
        if 'modified' in feed:
            seconds = time.mktime(feed['modified'])
            now = time.mktime(time.gmtime())
            when = utils.timeElapsed(now - seconds) + ' ago'
        else:
            when = "time unavailable"
        # The rest of the entries are all available in the channel key
        response = 'Title: %s;  URL: <%s>;  ' \
                   'Description: %s;  Last updated %s.' % (
                       info.get('title', 'unavailable').strip(),
                       info.get('link', 'unavailable').strip(),
                       info.get('description', 'unavailable').strip(),
                       when)
        irc.reply(' '.join(response.split()))


Class = RSS

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