#!/usr/bin/python -OO
# Copyright 2008-2017 The SABnzbd-Team <team@sabnzbd.org>
#
# 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; either version 2
# of the License, or (at your option) any later version.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

"""
sabnzbd.rss - rss client functionality
"""

import re
import logging
import time
import datetime
import threading

import sabnzbd
from sabnzbd.constants import RSS_FILE_NAME, DEFAULT_PRIORITY, NORMAL_PRIORITY, DUP_PRIORITY
from sabnzbd.decorators import synchronized
import sabnzbd.config as config
import sabnzbd.cfg as cfg
from sabnzbd.misc import cat_convert, wildcard_to_re, cat_to_opts, \
    match_str, from_units, int_conv, get_urlbase
import sabnzbd.emailer as emailer
from sabnzbd.encoding import unicoder, xml_name

import sabnzbd.utils.feedparser as feedparser

__RSS = None  # Global pointer to RSS-scanner instance


##############################################################################
# Wrapper functions
##############################################################################

def init():
    global __RSS
    __RSS = RSSQueue()


def stop():
    global __RSS
    if __RSS:
        __RSS.stop()
        try:
            __RSS.join()
        except:
            pass


def run_feed(feed, download, ignoreFirst=False, force=False, readout=True):
    global __RSS
    if __RSS:
        return __RSS.run_feed(feed, download, ignoreFirst, force=force, readout=readout)


def show_result(feed):
    global __RSS
    if __RSS:
        return __RSS.show_result(feed)


def flag_downloaded(feed, fid):
    global __RSS
    if __RSS:
        __RSS.flag_downloaded(feed, fid)


def lookup_url(feed, fid):
    global __RSS
    if __RSS:
        return __RSS.lookup_url(feed, fid)


def run_method():
    global __RSS
    if __RSS:
        return __RSS.run()
    else:
        return None


def next_run(t=None):
    global __RSS
    if __RSS:
        if t:
            __RSS.next_run = t
        else:
            return __RSS.next_run
    else:
        return time.time()


def save():
    global __RSS
    if __RSS:
        __RSS.save()


def clear_feed(feed):
    global __RSS
    if __RSS:
        __RSS.clear_feed(feed)


def clear_downloaded(feed):
    global __RSS
    if __RSS:
        __RSS.clear_downloaded(feed)


##############################################################################

def notdefault(item):
    """ Return True if not 'Default|''|*' """
    return bool(item) and str(item).lower() not in ('default', '*', '', str(DEFAULT_PRIORITY))


def convert_filter(text):
    """ Return compiled regex.
        If string starts with re: it's a real regex
        else quote all regex specials, replace '*' by '.*'
    """
    text = text.strip().lower()
    if text.startswith('re:'):
        txt = text[3:].strip()
    else:
        txt = wildcard_to_re(text)
    try:
        return re.compile(txt, re.I)
    except:
        logging.debug('Could not compile regex: %s', text)
        return None


def remove_obsolete(jobs, new_jobs):
    """ Expire G/B links that are not in new_jobs (mark them 'X')
        Expired links older than 3 days are removed from 'jobs'
    """
    now = time.time()
    limit = now - 259200  # 3days (3x24x3600)
    olds = jobs.keys()
    for old in olds:
        tm = jobs[old]['time']
        if old not in new_jobs:
            if jobs[old].get('status', ' ')[0] in ('G', 'B'):
                jobs[old]['status'] = 'X'
        if jobs[old]['status'] == 'X' and tm < limit:
            logging.debug("Purging link %s", old)
            del jobs[old]


LOCK = threading.RLock()


class RSSQueue(object):

    def __init__(self):
        self.jobs = {}
        self.next_run = time.time()
        self.shutdown = False

        try:
            self.jobs = sabnzbd.load_admin(RSS_FILE_NAME)
            if self.jobs:
                for feed in self.jobs:
                    remove_obsolete(self.jobs[feed], self.jobs[feed].keys())
        except:
            logging.warning(T('Cannot read %s'), RSS_FILE_NAME)
            logging.info("Traceback: ", exc_info=True)

        # Storage needs to be dict
        if not self.jobs:
            self.jobs = {}

        # jobs is a NAME-indexed dictionary
        #    Each element is link-indexed dictionary
        #        Each element is another dictionary:
        #           status : 'D', 'G', 'B', 'X' (downloaded, good-match, bad-match, obsolete)
        #               '*' added means: from the initial batch
        #               '-' added to 'D' means downloaded, but not displayed anymore
        #           title : Title
        #           url : URL
        #           cat : category
        #           orgcat : category as read from feed
        #           pp : pp
        #           script : script
        #           prio : priority
        #           time : timestamp (used for time-based clean-up)
        #           size : size in bytes
        #           age : age in datetime format as specified by feed
        #           season : season number (if applicable)
        #           episode : episode number (if applicable)

    def stop(self):
        self.shutdown = True

    @synchronized(LOCK)
    def run_feed(self, feed=None, download=False, ignoreFirst=False, force=False, readout=True):
        """ Run the query for one URI and apply filters """
        self.shutdown = False

        if not feed:
            return 'No such feed'

        newlinks = []
        new_downloads = []

        # Preparations, get options
        try:
            feeds = config.get_rss()[feed]
        except KeyError:
            logging.error(T('Incorrect RSS feed description "%s"'), feed)
            logging.info("Traceback: ", exc_info=True)
            return T('Incorrect RSS feed description "%s"') % feed

        uris = feeds.uri()
        defCat = feeds.cat()
        import sabnzbd.api
        if not notdefault(defCat) or defCat not in sabnzbd.api.list_cats(default=False):
            defCat = None
        defPP = feeds.pp()
        if not notdefault(defPP):
            defPP = None
        defScript = feeds.script()
        if not notdefault(defScript):
            defScript = None
        defPrio = feeds.priority()
        if not notdefault(defPrio):
            defPrio = None

        # Preparations, convert filters to regex's
        regexes = []
        reTypes = []
        reCats = []
        rePPs = []
        rePrios = []
        reScripts = []
        reEnabled = []
        for filter in feeds.filters():
            reCat = filter[0]
            if defCat in ('', '*'):
                reCat = None
            reCats.append(reCat)
            rePPs.append(filter[1])
            reScripts.append(filter[2])
            reTypes.append(filter[3])
            if filter[3] in ('<', '>', 'F', 'S'):
                regexes.append(filter[4])
            else:
                regexes.append(convert_filter(filter[4]))
            rePrios.append(filter[5])
            reEnabled.append(filter[6] != '0')
        regcount = len(regexes)

        # Set first if this is the very first scan of this URI
        first = (feed not in self.jobs) and ignoreFirst

        # Add sabnzbd's custom User Agent
        feedparser.USER_AGENT = 'SABnzbd+/%s' % sabnzbd.version.__version__

        # Read the RSS feed
        msg = None
        entries = None
        if readout:
            all_entries = []
            for uri in uris:
                uri = uri.replace(' ', '%20')
                logging.debug("Running feedparser on %s", uri)
                feed_parsed = feedparser.parse(uri.replace('feed://', 'http://'))
                logging.debug("Done parsing %s", uri)

                if not feed_parsed:
                    msg = T('Failed to retrieve RSS from %s: %s') % (uri, '?')
                    logging.info(msg)

                status = feed_parsed.get('status', 999)
                if status in (401, 402, 403):
                    msg = T('Do not have valid authentication for feed %s') % feed
                    logging.info(msg)

                if status >= 500 and status <= 599:
                    msg = T('Server side error (server code %s); could not get %s on %s') % (status, feed, uri)
                    logging.info(msg)

                entries = feed_parsed.get('entries')
                if 'bozo_exception' in feed_parsed and not entries:
                    msg = str(feed_parsed['bozo_exception'])
                    if 'CERTIFICATE_VERIFY_FAILED' in msg:
                        msg = T('Server %s uses an untrusted HTTPS certificate') % get_urlbase(uri)
                        msg += ' - https://sabnzbd.org/certificate-errors'
                        logging.error(msg)
                    else:
                        msg = T('Failed to retrieve RSS from %s: %s') % (uri, xml_name(msg))
                    logging.info(msg)

                if not entries:
                    msg = T('RSS Feed %s was empty') % uri
                    logging.info(msg)
                all_entries.extend(entries)
            entries = all_entries

        # In case of a new feed
        if feed not in self.jobs:
            self.jobs[feed] = {}
        jobs = self.jobs[feed]

        # Error in readout or now new readout
        if readout:
            if not entries:
                return unicoder(msg)
        else:
            entries = jobs.keys()

        # Filter out valid new links
        for entry in entries:
            if self.shutdown:
                return

            if readout:
                try:
                    link, category, size, age, season, episode = _get_link(uri, entry)
                except (AttributeError, IndexError):
                    link = None
                    category = u''
                    size = 0L
                    age = None
                    logging.info(T('Incompatible feed') + ' ' + uri)
                    logging.info("Traceback: ", exc_info=True)
                    return T('Incompatible feed')
                title = entry.title

                # If there's multiple feeds, remove the duplicates based on title and size
                if len(uris) > 1:
                    skip_job = False
                    for job_link, job in jobs.items():
                        # Allow 5% size deviation because indexers might have small differences for same release
                        if job.get('title') == title and link != job_link and (job.get('size')*0.95) < size < (job.get('size')*1.05):
                            logging.info("Ignoring job %s from other feed", title)
                            skip_job = True
                            break
                    if skip_job:
                        continue
            else:
                link = entry
                category = jobs[link].get('orgcat', '')
                if category in ('', '*'):
                    category = None
                title = jobs[link].get('title', '')
                size = jobs[link].get('size', 0L)
                age = jobs[link].get('age')
                season = jobs[link].get('season', 0)
                episode = jobs[link].get('episode', 0)

            if link:
                # Make sure spaces are quoted in the URL
                link = link.strip().replace(' ', '%20')

                newlinks.append(link)

                if link in jobs:
                    jobstat = jobs[link].get('status', ' ')[0]
                else:
                    jobstat = 'N'
                if jobstat in 'NGB' or (jobstat == 'X' and readout):
                    # Match this title against all filters
                    logging.debug('Trying title %s', title)
                    result = False
                    myCat = defCat
                    myPP = defPP
                    myScript = defScript
                    myPrio = defPrio
                    n = 0
                    if ('F' in reTypes or 'S' in reTypes) and (not season or not episode):
                        season, episode = sabnzbd.newsunpack.analyse_show(title)[1:3]

                    # Match against all filters until an positive or negative match
                    logging.debug('Size %s', size)
                    for n in xrange(regcount):
                        if reEnabled[n]:
                            if category and reTypes[n] == 'C':
                                found = re.search(regexes[n], category)
                                if not found:
                                    logging.debug("Filter rejected on rule %d", n)
                                    result = False
                                    break
                            elif reTypes[n] == '<' and size and from_units(regexes[n]) < size:
                                # "Size at most" : too large
                                logging.debug('Filter rejected on rule %d', n)
                                result = False
                                break
                            elif reTypes[n] == '>' and size and from_units(regexes[n]) > size:
                                # "Size at least" : too small
                                logging.debug('Filter rejected on rule %d', n)
                                result = False
                                break
                            elif reTypes[n] == 'F' and not ep_match(season, episode, regexes[n]):
                                # "Starting from SxxEyy", too early episode
                                logging.debug('Filter requirement match on rule %d', n)
                                result = False
                                break
                            elif reTypes[n] == 'S' and season and episode and ep_match(season, episode, regexes[n], title):
                                logging.debug('Filter matched on rule %d', n)
                                result = True
                                break
                            else:
                                if regexes[n]:
                                    found = re.search(regexes[n], title)
                                else:
                                    found = False
                                if reTypes[n] == 'M' and not found:
                                    logging.debug("Filter rejected on rule %d", n)
                                    result = False
                                    break
                                if found and reTypes[n] == 'A':
                                    logging.debug("Filter matched on rule %d", n)
                                    result = True
                                    break
                                if found and reTypes[n] == 'R':
                                    logging.debug("Filter rejected on rule %d", n)
                                    result = False
                                    break

                    if len(reCats):
                        if not result and defCat:
                            # Apply Feed-category on non-matched items
                            myCat = defCat
                        elif result and notdefault(reCats[n]):
                            # Use the matched info
                            myCat = reCats[n]
                        elif category and not defCat:
                            # No result and no Feed-category
                            myCat = cat_convert(category)

                        if myCat:
                            myCat, catPP, catScript, catPrio = cat_to_opts(myCat)
                        else:
                            myCat = catPP = catScript = catPrio = None
                        if notdefault(rePPs[n]):
                            myPP = rePPs[n]
                        elif not (reCats[n] or category):
                            myPP = catPP
                        if notdefault(reScripts[n]):
                            myScript = reScripts[n]
                        elif not (notdefault(reCats[n]) or category):
                            myScript = catScript
                        if rePrios[n] not in (str(DEFAULT_PRIORITY), ''):
                            myPrio = rePrios[n]
                        elif not ((rePrios[n] != str(DEFAULT_PRIORITY)) or category):
                            myPrio = catPrio


                    if cfg.no_dupes() and self.check_duplicate(title):
                        if cfg.no_dupes() == 1:
                            # Dupe-detection: Discard
                            logging.info("Ignoring duplicate job %s", title)
                            continue
                        elif cfg.no_dupes() == 3:
                            # Dupe-detection: Fail
                            # We accept it so the Queue can send it to the History
                            logging.info("Found duplicate job %s", title)
                        else:
                            # Dupe-detection: Pause
                            myPrio = DUP_PRIORITY

                    act = download and not first
                    if link in jobs:
                        act = act and not jobs[link].get('status', '').endswith('*')
                        act = act or force
                        star = first or jobs[link].get('status', '').endswith('*')
                    else:
                        star = first
                    if result:
                        _HandleLink(jobs, feed, link, title, size, age, season, episode, 'G', category, myCat, myPP,
                                     myScript, act, star, priority=myPrio, rule=str(n))
                        if act:
                            new_downloads.append(title)
                    else:
                        _HandleLink(jobs, feed, link, title, size, age, season, episode, 'B', category, myCat, myPP,
                                     myScript, False, star, priority=myPrio, rule=str(n))

        # Send email if wanted and not "forced"
        if new_downloads and cfg.email_rss() and not force:
            emailer.rss_mail(feed, new_downloads)

        remove_obsolete(jobs, newlinks)
        return msg

    def run(self):
        """ Run all the URI's and filters """
        if not sabnzbd.PAUSED_ALL:
            active = False
            if self.next_run < time.time():
                self.next_run = time.time() + cfg.rss_rate.get() * 60
            feeds = config.get_rss()
            for feed in feeds.keys():
                try:
                    if feeds[feed].enable.get():
                        logging.info('Starting scheduled RSS read-out for "%s"', feed)
                        active = True
                        self.run_feed(feed, download=True, ignoreFirst=True)
                        # Wait 15 seconds, else sites may get irritated
                        for unused in xrange(15):
                            if self.shutdown:
                                return
                            else:
                                time.sleep(1.0)
                except KeyError:
                    # Feed must have been deleted
                    pass
            if active:
                self.save()
                logging.info('Finished scheduled RSS read-outs')

    @synchronized(LOCK)
    def show_result(self, feed):
        if feed in self.jobs:
            try:
                return self.jobs[feed]
            except:
                return {}
        else:
            return {}

    @synchronized(LOCK)
    def save(self):
        sabnzbd.save_admin(self.jobs, RSS_FILE_NAME)

    @synchronized(LOCK)
    def delete(self, feed):
        if feed in self.jobs:
            del self.jobs[feed]

    @synchronized(LOCK)
    def flag_downloaded(self, feed, fid):
        if feed in self.jobs:
            lst = self.jobs[feed]
            for link in lst:
                if lst[link].get('url', '') == fid:
                    lst[link]['status'] = 'D'
                    lst[link]['time_downloaded'] = time.localtime()

    @synchronized(LOCK)
    def lookup_url(self, feed, url):
        if url and feed in self.jobs:
            lst = self.jobs[feed]
            for link in lst:
                if lst[link].get('url') == url:
                    return lst[link]
        return None

    @synchronized(LOCK)
    def clear_feed(self, feed):
        # Remove any previous references to this feed name, and start fresh
        if feed in self.jobs:
            del self.jobs[feed]

    @synchronized(LOCK)
    def clear_downloaded(self, feed):
        # Mark downloaded jobs, so that they won't be displayed any more.
        if feed in self.jobs:
            for item in self.jobs[feed]:
                if self.jobs[feed][item]['status'] == 'D':
                    self.jobs[feed][item]['status'] = 'D-'

    def check_duplicate(self, title):
        """ Check if this title was in this or other feeds
            Return matching feed name
        """
        title = title.lower()
        for fd in self.jobs:
            for lk in self.jobs[fd]:
                item = self.jobs[fd][lk]
                if item.get('status', ' ')[0] == 'D' and \
                   item.get('title', '').lower() == title:
                    return fd
        return ''


def _HandleLink(jobs, feed, link, title, size, age, season, episode, flag, orgcat, cat, pp, script,
                download, star, priority=NORMAL_PRIORITY, rule=0):
    """ Process one link """
    if script == '':
        script = None
    if pp == '':
        pp = None

    jobs[link] = {}
    jobs[link]['title'] = title
    jobs[link]['url'] = link
    jobs[link]['cat'] = cat
    jobs[link]['pp'] = pp
    jobs[link]['script'] = script
    jobs[link]['prio'] = str(priority)
    jobs[link]['orgcat'] = orgcat
    jobs[link]['size'] = size
    jobs[link]['age'] = age
    jobs[link]['time'] = time.time()
    jobs[link]['rule'] = rule
    jobs[link]['season'] = season
    jobs[link]['episode'] = episode

    if special_rss_site(link):
        nzbname = None
    else:
        nzbname = title

    if download:
        jobs[link]['status'] = 'D'
        jobs[link]['time_downloaded'] = time.localtime()
        logging.info("Adding %s (%s) to queue", link, title)
        sabnzbd.add_url(link, pp=pp, script=script, cat=cat, priority=priority, nzbname=nzbname)
    else:
        if star:
            jobs[link]['status'] = flag + '*'
        else:
            jobs[link]['status'] = flag

def _get_link(uri, entry):
    """ Retrieve the post link from this entry
        Returns (link, category, size)
    """
    link = None
    category = ''
    size = 0L
    uri = uri.lower()
    age = datetime.datetime.now()

    # Try standard link and enclosures first
    link = entry.link
    if not link:
        link = entry.links[0].href
    if 'enclosures' in entry:
        try:
            link = entry.enclosures[0]['href']
            size = int(entry.enclosures[0]['length'])
        except:
            pass

    if size == 0L:
        _RE_SIZE1 = re.compile(r'Size:\s*(\d+\.\d+\s*[KMG]{0,1})B\W*', re.I)
        _RE_SIZE2 = re.compile(r'\W*(\d+\.\d+\s*[KMG]{0,1})B\W*', re.I)
        # Try to find size in Description
        try:
            desc = entry.description.replace('\n', ' ').replace('&nbsp;', ' ')
            m = _RE_SIZE1.search(desc) or _RE_SIZE2.search(desc)
            if m:
                size = from_units(m.group(1))
        except:
            pass

    # Try newznab attribute first, this is the correct one
    try:
        # Convert it to format that calc_age understands
        age = datetime.datetime(*entry['newznab']['usenetdate_parsed'][:6])
    except:
        # Date from feed (usually lags behind)
        try:
            # Convert it to format that calc_age understands
            age = datetime.datetime(*entry.published_parsed[:6])
        except:
            pass
    finally:
        # We need to convert it to local timezone, feedparser always returns UTC
        age = age - datetime.timedelta(seconds=time.timezone)

    # Maybe the newznab also provided SxxExx info
    try:
        season = re.findall('\d+', entry['newznab']['season'])[0]
        episode = re.findall('\d+', entry['newznab']['episode'])[0]
    except:
        season = episode = 0

    if link and 'http' in link.lower():
        try:
            category = entry.cattext
        except:
            try:
                category = entry.category
            except:
                try:  # nzb.su
                    category = entry.tags[0]['term']
                except:
                    try:
                        category = entry.description
                    except:
                        category = ''

        return link, category, size, age, season, episode
    else:
        logging.warning(T('Empty RSS entry found (%s)'), link)
        return None, '', 0L, None, 0, 0


def special_rss_site(url):
    """ Return True if url describes an RSS site with odd titles """
    return cfg.rss_filenames() or match_str(url, cfg.rss_odd_titles())


_RE_SP = re.compile(r's*(\d+)[ex](\d+)', re.I)
def ep_match(season, episode, expr, title=None):
    """ Return True if season, episode is at or above expected
        Optionally `title` can be matched
    """
    m = _RE_SP.search(expr)
    if m:
        # Make sure they are all integers for comparison
        req_season = int(m.group(1))
        req_episode = int(m.group(2))
        season = int_conv(season)
        episode = int_conv(episode)
        if season > req_season or (season == req_season and episode >= req_episode):
            if title:
                show = expr[:m.start()].replace('.', ' ').replace('_', ' ').strip()
                show = show.replace(' ', '[._ ]+')
                return bool(re.search(show, title, re.I))
            else:
                return True
        else:
            return False
    else:
        return True
