#!/usr/bin/env python3
# vim: ai ts=4 sts=4 sw=4
"""PostgreSQL Planet Aggregator

This file contains the functions to synchronize the list
of twitter handles with a list on the twitter account.

Copyright (C) 2009-2019 PostgreSQL Global Development Group
"""

import psycopg2
import psycopg2.extensions
import configparser
from twitterclient import TwitterClient


class SyncTwitter(TwitterClient):
    def __init__(self, cfg):
        TwitterClient.__init__(self, cfg)

        psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
        self.db = psycopg2.connect(cfg.get('planet', 'db'))

    def Run(self):
        # Get list of handles that should be on the list
        curs = self.db.cursor()
        curs.execute("SELECT DISTINCT lower(twitteruser) FROM feeds WHERE approved AND NOT (twitteruser IS NULL OR twitteruser='') ORDER BY lower(twitteruser)")
        expected = set([r[0].replace('@', '') for r in curs.fetchall()])

        # Get list of current screen names the list is following
        current = set(self.list_subscribers())

        # Start by deleting, then adding the new ones
        for s in current.difference(expected):
            # We don't care about the return code and just keep running if it
            # fails, since we will try again later.
            self.remove_subscriber(s)
        for s in expected.difference(current):
            # If we fail to add a subscriber, stop trying
            if not self.add_subscriber(s):
                # Most likely it's things like it doesn't exist or we don't have permissions
                # to follow it.
                print("Failed to add twitter subscriber {0}, removing from feed record".format(s))

                # To be on the safe side, store the old twitter username. In case the twitter APIs
                # go bonkers on us and we end up removing too much.
                curs.execute("UPDATE feeds SET oldtwitteruser=twitteruser, twitteruser='' WHERE lower(twitteruser)=%(twitter)s", {
                    'twitter': s,
                })
        self.db.commit()


if __name__ == "__main__":
    c = configparser.ConfigParser()
    c.read('planet.ini')
    SyncTwitter(c).Run()