"""Scheduled task for updating user preferences based on stream viewing."""

import json

from celery import shared_task
from database.database import Database
import redis

REDIS_URL = "redis://redis:6379/1"
r = redis.from_url(REDIS_URL, decode_responses=True)

@shared_task
def user_preferences():
    """
    Updates users preferences on different stream categories
    based on the streams they are currently watching
    """
    stats = r.hget("current_viewers", "viewers")
    # If there are any current viewers
    if stats:
        stats = json.loads(stats)
        with Database() as db:
            # Loop over all users and their currently watching streams
            for user_id, stream_ids in stats.items():
                # For each user and stream combination
                for stream_id in stream_ids:
                    # Retrieves category associated with stream
                    current_category = db.fetchone(
                        """SELECT category_id FROM streams
                           WHERE user_id = ?
                        """, (stream_id,))
                    # If stream is still live then update the
                    # user_preferences table to reflect their preferences
                    if current_category:
                        db.execute(
                            """INSERT INTO user_preferences
                               (user_id,category_id,favourability)
                               VALUES (?,?,?)
                               ON CONFLICT(user_id, category_id)
                               DO UPDATE SET
                               favourability = favourability + 1
                            """, (user_id,
                                  current_category["category_id"], 1))