#!/usr/bin/env python
#
#   RssDB
#

import sys
import sqlite3
import bz2
import binascii
import pickle
import logging
from time import strftime

# available at http://feedparser.org or http://code.google.com/p/feedparser/ 
import feedparser     
 
__version='0.1' 

class RssDB():
    '''
    RSS database
    '''
    def __init__(self, database='rss.sqlite', thread_limit=3):
        '''
        init
        
        database        - database
        treads_limit    - threads limit
        '''
        self.__db_conn = sqlite3.connect(database)
        self.__db_conn.row_factory = sqlite3.Row
        self.__db_cursor = self.__db_conn.cursor()
 
        #insert initial values into feed database
        self.__db_cursor.execute('CREATE TABLE IF NOT EXISTS feeds (id INTEGER PRIMARY KEY AUTOINCREMENT, url VARCHAR(1000) UNIQUE);')
        self.__db_cursor.execute('CREATE TABLE IF NOT EXISTS entries (feed_id, link UNIQUE, data);')
        
        # logging
        self.__logger = logging.getLogger(database.split('.')[0])
        self.__logger.setLevel(logging.DEBUG)
        # console handler
        ch = logging.StreamHandler()
        ch.setLevel(logging.DEBUG)
        # formatter
        ch.setFormatter(logging.Formatter('%(asctime)s;%(name)s;%(levelname)s: %(message)s'))
        self.__logger.addHandler(ch)

    def log(self, level, message):
        '''
        logging message
        '''
        if level == 'debug': self.__logger.debug(message)
        elif level == 'info': self.__logger.info(message)
        elif level == 'warn': self.__logger.warn(message)
        elif level == 'error': self.__logger.error(message)
        elif level == 'critical': self.__logger.critical(message)
        else: print "Warning! Unkown logging level"
        
        
    def sync(self):
        '''
        RSS DB Commit
        '''
        self.__db_conn.commit()

    def compress_data(self, data):
        '''
        compress data
        '''
        return binascii.hexlify(bz2.compress(data))

        
    def feeds(self):
        '''
        return list of feeds in database
        '''
        return self.__db_cursor.execute('SELECT id, url FROM feeds').fetchall()
        
    def add_feed(self, feed):
        '''
        add feed to database
        
        return:
        True - if feed was added
        False - if feed wasn't added
        '''
        try:
            self.__db_cursor.execute('INSERT INTO feeds (url) VALUES ("%s");' % feed)
            self.sync()
            return True
        except sqlite3.IntegrityError:
            return False

    def update_feed_entries(self):
        '''
        update feed entries
        '''
        for info in self.feeds(): 
            self.log('info', (info['url']))
            entries = feedparser.parse(info['url']).entries
            self.store_feed_items(info['id'], entries)

            
    def store_feed_items(self, id, items):
        '''
        Takes a feed_id and a list of items and stored them in the DB 
        '''
        new_items = 0
        for entry in items:
            self.__db_cursor.execute('SELECT link from entries WHERE link="%s"' % entry.link)
            if len(self.__db_cursor.fetchall()) == 0:
                self.__db_cursor.execute('INSERT INTO entries (feed_id, link, data) VALUES (?,?,?)', \
                        (id, entry.link, self.compress_data(pickle.dumps(dict(entry)))))
                new_items += 1
        self.sync()
        if new_items > 0: self.log('info', 'new items: %d' % new_items)
        
    def remove_entries(self):
        '''
        Remove entries
        '''
        self.__db_cursor.execute("DELETE FROM entries;")
        self.__db_cursor.execute("VACUUM;")
        self.sync()
 
    def statistics(self):
        '''
        show statistics
        '''
        print "Total feeds: %d" % self.__db_cursor.execute('SELECT count(*) FROM feeds;').fetchone()[0]
        print "Total entries: %d" % self.__db_cursor.execute('SELECT count(*) FROM entries;').fetchone()[0]
        print "Feeds:"
        for info in self.feeds():
            print "entries: % 5d, feed: %s" % \
                    (self.__db_cursor.execute('SELECT count(*) FROM entries WHERE feed_id=%d;' % info[0]).fetchone()[0], 
                    info[1])
        
if __name__ == "__main__":
    from optparse import OptionParser
    parser = OptionParser(version="%prog, v." + __version)
    parser.add_option("-d", "--database", dest="database", help="RSS database, by default: rss.sqlite")
    parser.add_option("-a", "--add_feed", dest="add_feed", help="add feed link to database")
    parser.add_option("-l", "--feed_list", action='store_true', dest="feed_list", 
                        default=False, help="printout feed list in database")
    parser.add_option("-u", "--update_feed_entries", action='store_true', dest="update_feed_entries", 
                        default=False, help="update feed entries")
    parser.add_option("-s", "--statistics", action='store_true', dest="statistics", 
                        default=False, help="show statistics")
    parser.add_option("-r", "--remove_entries", action='store_true', dest="remove_entries", 
                        default=False, help="remove entries")
    (options, args) = parser.parse_args()

    # definition of database
    if options.database:
        rss_db = RssDB(database=options.database)
    else:
        rss_db = RssDB()
    
    # action: add new feed
    if options.add_feed:
        if rss_db.add_feed(options.add_feed):
            rss_db.log('info', 'Feed: %s was added' % options.add_feed)
        else:
            rss_db.log('warn', 'Feed: %s wasn\'t added' % options.add_feed)
        sys.exit()
    
    # action: print out list of feeds
    elif options.feed_list:
        for feed in rss_db.feeds():
            print "%03d:%s" % (feed[0], feed[1])
        
        sys.exit()
    
    # action: update for new feed entries
    elif options.update_feed_entries:
        try:
            rss_db.update_feed_entries()
        except KeyboardInterrupt:
            print "Interrupted by user"
        
        sys.exit()
    
    # printout statistics
    elif options.statistics:
        print "Statistics"
        rss_db.statistics()
        
        sys.exit()

    # remove entries
    elif options.remove_entries:
        print "Remove feed entries"
        rss_db.remove_entries()
        
        sys.exit()
        
    else:
        print "No arguments. Please use -h for help"