#! /usr/bin/env python
#-*- coding: utf-8 -*-

# pyAggr3g470r - A Web based news aggregator.
# Copyright (C) 2010-2013  Cédric Bonhomme - http://cedricbonhomme.org/
#
# For more information : http://bitbucket.org/cedricbonhomme/pyaggr3g470r/
#
# 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 3 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, see <http://www.gnu.org/licenses/>

__author__ = "Cedric Bonhomme"
__version__ = "$Revision: 1.6 $"
__date__ = "$Date: 2010/12/07 $"
__revision__ = "$Date: 2013/11/17 $"
__copyright__ = "Copyright (c) Cedric Bonhomme"
__license__ = "GPLv3"

#
# This file provides functions used for:
# - the database management;
# - generation of tags cloud;
# - HTML processing;
# - e-mail notifications.
#

import os
import re
import glob
import opml
import operator
import calendar

from BeautifulSoup import BeautifulSoup

from collections import Counter
from contextlib import contextmanager

import conf
import models

# regular expression to check URL
url_finders = [ \
    re.compile("([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}|(((news|telnet|nttp|file|http|ftp|https)://)|(www|ftp)[-A-Za-z0-9]*\\.)[-A-Za-z0-9\\.]+)(:[0-9]*)?/[-A-Za-z0-9_\\$\\.\\+\\!\\*\\(\\),;:@&=\\?/~\\#\\%]*[^]'\\.}>\\),\\\"]"), \
    re.compile("([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}|(((news|telnet|nttp|file|http|ftp|https)://)|(www|ftp)[-A-Za-z0-9]*\\.)[-A-Za-z0-9\\.]+)(:[0-9]*)?"), \
    re.compile("(~/|/|\\./)([-A-Za-z0-9_\\$\\.\\+\\!\\*\\(\\),;:@&=\\?/~\\#\\%]|\\\\)+"), \
    re.compile("'\\<((mailto:)|)[-A-Za-z0-9\\.]+@[-A-Za-z0-9\\.]+") \
]

#import log
#pyaggr3g470r_log = log.Log()

@contextmanager
def opened_w_error(filename, mode="r"):
    try:
        f = open(filename, mode)
    except IOError as err:
        yield None, err
    else:
        try:
            yield f, None
        finally:
            f.close()

def import_opml(email, opml_file):
    """
    Import new feeds from an OPML file.
    """
    user = models.User.objects(email=email).first()
    try:
        subscriptions = opml.parse(opml_file)
    except Exception as e:
        raise e
    for subscription in subscriptions:
        existing_feed = [feed for feed in user.feeds if feed.link == subscription.xmlUrl]
        if len(existing_feed) == 0:
            new_feed = models.Feed(title=subscription.title, description=subscription.description, link=subscription.xmlUrl, \
                                    site_link=subscription.htmlUrl, email=False, enabled=True)
            user.feeds.append(new_feed)
    user.save()

def open_url(url):
    """
    Open an URL with the proxy and the user-agent
    specified in the configuration file.
    """
    if conf.HTTP_PROXY == "":
        proxy = {}
    else:
        proxy = {"http" : conf.HTTP_PROXY}
    opener = urllib.request.FancyURLopener(proxy)
    try:
        opener = urllib.request.build_opener()
        opener.addheaders = [('User-agent', conf.USER_AGENT)]
        return (True, opener.open(url))
    except urllib.error.HTTPError as e:
        # server couldn't fulfill the request
        error = (url, e.code, \
                        http.server.BaseHTTPRequestHandler.responses[e.code][1])
        #pyaggr3g470r_log.error(url + " " + str(e.code) + " " + http.server.BaseHTTPRequestHandler.responses[e.code][1])
        return (False, error)
    except urllib.error.URLError as e:
        # failed to reach the server
        if type(e.reason) == str:
            error = (url, e.reason, e.reason)
            #pyaggr3g470r_log.error(url + " " + e.reason)
        else:
            error = (url, e.reason.errno, e.reason.strerror)
            #pyaggr3g470r_log.error(url + " " + str(e.reason.errno) + " " + e.reason.strerror)
        return (False, error)

def clear_string(data):
    """
    Clear a string by removing HTML tags, HTML special caracters
    and consecutive white spaces (more that one).
    """
    p = re.compile('<[^>]+>') # HTML tags
    q = re.compile('\s') # consecutive white spaces
    return p.sub('', q.sub(' ', data))

def load_stop_words():
    """
    Load the stop words and return them in a list.
    """
    stop_words_lists = glob.glob('./pyaggr3g470r/var/stop_words/*.txt')
    stop_words = []

    for stop_wods_list in stop_words_lists:
        with opened_w_error(stop_wods_list, "r") as (stop_wods_file, err):
            if err:
                stop_words = []
            else:
                stop_words += stop_wods_file.read().split(";")
    return stop_words

def top_words(articles, n=10, size=5):
    """
    Return the n most frequent words in a list.
    """
    stop_words = load_stop_words()
    words = Counter()
    wordre = re.compile(r'\b\w{%s,}\b' % size, re.I)
    for article in articles:
        for word in [elem.lower() for elem in
                wordre.findall(clear_string(article.content)) \
                if elem.lower() not in stop_words]:
            words[word] += 1
    return words.most_common(n)

def tag_cloud(tags):
    """
    Generates a tags cloud.
    """
    tags.sort(key=operator.itemgetter(0))
    return '\n'.join([('<font size=%d><a href="/search/?query=%s" title="Count: %s">%s</a></font>' % \
                    (min(1 + count * 7 / max([tag[1] for tag in tags]), 7), word, format(count, ',d'), word)) \
                        for (word, count) in tags])

def search_feed(url):
    """
    Search a feed in a HTML page.
    """
    soup, page = None, None
    try:
        result = open_url(url)
        if result[0] == True:
            page = open_url(url)[1]
        else:
            return None
        soup = BeautifulSoup(page)
    except:
        return None
    feed_links = soup('link', type='application/atom+xml')
    feed_links.extend(soup('link', type='application/rss+xml'))
    for feed_link in feed_links:
        #if url not in feed_link['href']:
            #return urllib.parse.urljoin(url, feed_link['href'])
        return feed_link['href']
    return None