from datetime import timedelta

from django.contrib.auth import get_user_model
from django.db.models import Count, Q
from django.utils import timezone

from misago.categories.models import Category
from misago.conf import settings
from misago.threads.models import Post

from .models import ActivityRanking


UserModel = get_user_model()


def get_active_posters_ranking():
    users = []

    queryset = ActivityRanking.objects.select_related('user', 'user__rank')
    for ranking in queryset.order_by('-score'):
        ranking.user.score = ranking.score
        users.append(ranking.user)

    return {
        'users': users,
        'users_count': len(users),
    }


def build_active_posters_ranking():
    tracked_period = settings.MISAGO_RANKING_LENGTH
    tracked_since = timezone.now() - timedelta(days=tracked_period)

    ActivityRanking.objects.all().delete()

    ranked_categories = []
    for category in Category.objects.all_categories():
        ranked_categories.append(category.pk)

    ranked_posts = Q(posted_on__gte=tracked_since) & Q(category__in=ranked_categories)

    queryset = (
        UserModel.objects
        .filter(is_active=True)
        .annotate(score=Count('post', filter=ranked_posts))
        .order_by('-score')
    )[:settings.MISAGO_RANKING_SIZE]

    new_ranking = []
    for ranking in queryset.iterator():
        new_ranking.append(ActivityRanking(user=ranking, score=ranking.score))
    ActivityRanking.objects.bulk_create(new_ranking)