from datetime import timedelta

from django.conf import settings
from django.contrib.auth import get_user_model
from django.core.urlresolvers import reverse
from django.db.models import Count
from django.http import Http404
from django.shortcuts import redirect, render as django_render
from django.utils import timezone

from misago.forums.models import Forum
from misago.core.cache import cache
from misago.core.shortcuts import get_object_or_404, paginate

from misago.users.models import Rank
from misago.users.online.utils import get_online_queryset
from misago.users.pages import users_list
from misago.users.permissions.profiles import (allow_browse_users_list,
                                               allow_see_users_online_list)


def render(request, template, context):
    context['pages'] = users_list.get_pages(request)

    for page in context['pages']:
        page['reversed_link'] = reverse(page['link'])

    active_rank = context.get('rank')
    for rank in Rank.objects.filter(is_tab=True).order_by('order'):
        context['pages'].append({
            'name': rank.name,
            'reversed_link': reverse('misago:users_rank',
                                     kwargs={'rank_slug': rank.slug}),
            'is_active': active_rank.pk == rank.pk if active_rank else None
        })

    for page in context['pages']:
        if page['is_active']:
            context['active_page'] = page
            break

    return django_render(request, template, context)


def allow_see_list(permission=None):
    def permission_decorator(f):
        def decorator(request, *args, **kwargs):
            allow_browse_users_list(request.user)
            if permission:
                permission(request.user)
            return f(request, *args, **kwargs)
        return decorator
    return permission_decorator


@allow_see_list()
def lander(request):
    default = users_list.get_default_link()
    return redirect(default)


def list_view(request, template, queryset, page, context=None):
    context = context or {}
    context['users'] = paginate(queryset, page, 6 * 3, 5)
    return render(request, template, context)


@allow_see_list()
def active_posters(request, page=0):
    ranking = get_active_posters_rankig()

    template = "misago/userslists/active_posters.html"
    return render(request, template, {
        'tracked_period': settings.MISAGO_RANKING_LENGTH,
        'users': ranking['users'],
        'users_count': ranking['users_count']
    })


def get_active_posters_rankig():
    cache_key = 'misago_active_posters_ranking'
    ranking = cache.get(cache_key, 'nada')
    if ranking == 'nada':
        ranking = get_real_active_posts_ranking()
        cache.set(cache_key, ranking, 18*3600)
    return ranking


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

    ranked_forums = [forum.pk for forum in Forum.objects.all_forums()]

    User = get_user_model()
    queryset = User.objects.filter(posts__gt=0)
    queryset = queryset.filter(post__posted_on__gte=tracked_since,
                               post__forum__in=ranked_forums)
    queryset = queryset.annotate(num_posts=Count('post'))
    queryset = queryset.select_related('user__rank')
    queryset = queryset.order_by('-num_posts')

    queryset = queryset[:settings.MISAGO_RANKING_SIZE]

    return {
        'users': [user for user in queryset],
        'users_count': queryset.count()
    }


@allow_see_list(allow_see_users_online_list)
def online(request, page=0):
    queryset = get_online_queryset(request.user).order_by('user__slug')
    queryset = queryset.select_related('user__rank')

    template = "misago/userslists/online.html"
    try:
        return list_view(request, template, queryset, page, {
            'data_from': timezone.now()
        })
    except Http404:
        return redirect('misago:users_online')


@allow_see_list()
def rank(request, rank_slug, page=0):
    rank = get_object_or_404(Rank.objects.filter(is_tab=True), slug=rank_slug)
    queryset = rank.user_set.order_by('slug')

    template = "misago/userslists/rank.html"
    return list_view(request, template, queryset, page, {'rank': rank})