# -*- coding: utf-8 -*-
#
# Copyright Grégory Soutadé 2015

# This file is part of iwla

# iwla 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 3 of the License, or
# (at your option) any later version.
#
# iwla 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 iwla.  If not, see <http://www.gnu.org/licenses/>.
#

import re

from iwla import IWLA
from iplugin import IPlugin

"""
Post analysis hook

Find feeds parsers (first hit in feeds conf value and no viewed pages if it's a robot)
If merge_feeds_parsers is set to True, merge feeds parsers with the same user agent
as it must be the same person with a different IP address.

Warning : When merge_feeds_parsers is activated, last access display date is the more
recent date of all merged parsers found

Plugin requirements :
    None

Conf values needed :
    feeds
    feeds_referers*
    merge_feeds_parsers*

Output files :
    None

Statistics creation :
   remote_addr =>
       feed_parser
       feed_name_analysed

Statistics update :
    None

Statistics deletion :
    None
"""

class IWLAPostAnalysisFeeds(IPlugin):
    NOT_A_FEED_PARSER = 0
    FEED_PARSER = 1
    MERGED_FEED_PARSER = 2
    BAD_FEED_PARSER = 3

    def __init__(self, iwla):
        super(IWLAPostAnalysisFeeds, self).__init__(iwla)
        self.API_VERSION = 1
        self.conf_requires = ['feeds']

    def load(self):
        feeds = self.iwla.getConfValue('feeds', [])
        feeds_referers = self.iwla.getConfValue('feeds_referers', [])
        self.merge_feeds_parsers = self.iwla.getConfValue('merge_feeds_parsers', False)
        _merge_feeds_parsers_list = self.iwla.getConfValue('merge_feeds_parsers_list', [])

        if feeds is None: return False

        self.feeds_re = []
        for f in feeds:
            self.feeds_re.append(re.compile(f))

        self.bad_feeds_re = []
        self.bad_feeds_re.append(re.compile(r'.*crawl.*'))

        self.user_agents_re = []
        self.user_agents_re.append(re.compile(r'.*rss.*'))
        self.user_agents_re.append(re.compile(r'.*atom.*'))
        self.user_agents_re.append(re.compile(r'.*feed.*'))

        self.referers_uri = []
        for f in feeds_referers:
            self.referers_uri.append(f)

        self.merge_feeds_parsers_list = []
        for f in _merge_feeds_parsers_list:
            self.merge_feeds_parsers_list.append(re.compile(f))
            
        self.merged_feeds = {}

        return True

    def _appendToMergeCache(self, isFeedParser, key, hit):
        # First time, register into dict
        if self.merged_feeds.get(key, None) is None:
            # Merged
            self.merged_feeds[key] = hit
        elif hit['remote_ip'] != self.merged_feeds[key]['remote_ip']:
            # Next time
            # Current must be ignored
            hit['feed_parser'] = self.NOT_A_FEED_PARSER
            last_access = hit['last_access']
            # Previous matched hit must be set as merged
            isFeedParser = self.MERGED_FEED_PARSER
            hit = self.merged_feeds[key]
            if hit['last_access'] < last_access:
                hit['feed_parser_last_access'] = last_access
            else:
                hit['feed_parser_last_access'] = hit['last_access']
        hit['feed_parser'] = isFeedParser
    
    def mergeFeedsParsers(self, isFeedParser, hit):
        if isFeedParser:
            for r in self.merge_feeds_parsers_list:
                if r.match(hit['remote_addr']) or r.match(hit['remote_ip']):
                    self._appendToMergeCache(isFeedParser, r, hit)
                    return
            #print("No match for %s : %d" % (hit['remote_addr'], hit['viewed_hits'][0] + hit['not_viewed_hits'][0]))
            # Other cases, look for user agent
            user_agent = hit['requests'][0]['http_user_agent'].lower()
            self._appendToMergeCache(isFeedParser, user_agent, hit)

    def hook(self):
        hits = self.iwla.getCurrentVisits()
        for hit in hits.values():
            isFeedParser = hit.get('feed_parser', None)

            # Register already tagged feed parser in merged_feeds
            if self.merge_feeds_parsers and\
               not isFeedParser in (None, self.BAD_FEED_PARSER):
                self.mergeFeedsParsers(isFeedParser, hit)
                continue

            if isFeedParser:
                if hit['feed_parser'] == self.BAD_FEED_PARSER: continue
                if not hit.get('feed_name_analysed', False) and\
                   hit.get('dns_name_replaced', False):
                    hit['feed_name_analysed'] = True
                    addr = hit.get('remote_addr', None)
                    for r in self.bad_feeds_re:
                        if r.match(addr):
                            hit['feed_parser'] = self.BAD_FEED_PARSER
                            break
                continue

            request = hit['requests'][0]
            isFeedParser = self.NOT_A_FEED_PARSER
            uri = request['extract_request']['extract_uri'].lower()
            for regexp in self.feeds_re:
                if regexp.match(uri):
                    isFeedParser = self.FEED_PARSER
                    # Robot that views pages -> bot
                    if hit['robot']:
                        if hit['not_viewed_pages'][0]:
                            isFeedParser = self.NOT_A_FEED_PARSER
                    break

            if isFeedParser == self.NOT_A_FEED_PARSER:
                user_agent = request['http_user_agent'].lower()
                for regexp in self.user_agents_re:
                    if regexp.match(user_agent):
                        isFeedParser = self.FEED_PARSER
                        break
                
            if isFeedParser == self.NOT_A_FEED_PARSER and\
               request.get('extract_referer', False):
                referer = request['extract_referer']['extract_uri'].lower()
                for uri in self.referers_uri:
                    if referer == uri:
                        isFeedParser = self.FEED_PARSER
                        break

            if self.merge_feeds_parsers:
                self.mergeFeedsParsers(isFeedParser, hit)
            else:
                hit['feed_parser'] = isFeedParser