from django.conf import settings
from django.core.cache import cache
from django.core.paginator import Paginator
from django.db.models import Count, F, Q, Sum
from django.http import JsonResponse
from django.shortcuts import get_object_or_404, redirect
from django.urls import reverse
from django.views import View
from django.views.generic import DetailView, ListView, TemplateView

from ..models import Album, Photo, Redir


class PhotosList(ListView):
    """Shows all public photos sorted by user-selected ordering."""
    model = Photo
    paginate_by = 30

    def get_queryset(self):
        ordering_options = {
            'latest': '-taken_at',
            'liked': '-likes',
            'popular': '-views',
            'favorite': '-is_favorite',
        }
        selected_order = self.request.GET.get('order', 'latest')
        order = ordering_options.get(selected_order, ordering_options['latest'])
        return Photo.objects.filter(album__is_public=True).order_by(order).select_related('album')

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)

        # Canonical_url
        page = self.request.GET.get('page')
        if page and page != '1':
            canonical_url = f"{self.request.build_absolute_uri(reverse('gallery:photos_url'))}?page={page}"
        else:
            canonical_url = self.request.build_absolute_uri(reverse('gallery:photos_url'))

        context.update({
            'order': self.request.GET.get('order', 'latest'),
            'canonical_url': canonical_url,
        })
        return context


class PhotoDetail(DetailView):
    """Shows a single photo and handles liking functionality."""
    model = Photo
    slug_url_kwarg = 'photo_slug'
    template_name = 'gallery/photo_detail.html'

    def get_object(self, queryset=None):
        album_slug = self.kwargs.get('album_slug')
        photo_slug = self.kwargs.get('photo_slug')
        photo = get_object_or_404(Photo.objects.select_related('album'), slug=photo_slug, album__slug=album_slug)

        if photo.slug not in self.request.session:
            photo.add_view()
            self.request.session[photo.slug] = 0

        return photo

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context.update({
            'next': self.object.get_next(),
            'prev': self.object.get_prev(),
            'canonical_url': self.request.build_absolute_uri(self.object.get_absolute_url()),
            'liked': self.request.session.get(f"liked_{self.object.slug}", False)
        })
        return context


class PhotoLike(View):
    """Ajax like photo button."""

    def get(self, request, *args, **kwargs):
        return JsonResponse({'error': 'This endpoint only supports POST requests.'}, status=405)

    def post(self, request, album_slug, photo_slug):
        photo = get_object_or_404(Photo.objects.select_related('album'), slug=photo_slug, album__slug=album_slug)
        session_key = f"liked_{photo.slug}"
        liked = request.session.get(session_key, False)

        if not liked:
            photo.likes += 1
            if request.user.is_authenticated:
                photo.is_favorite = True
            request.session[session_key] = True
            status = "liked"
        else:
            photo.likes = max(0, photo.likes - 1)
            if request.user.is_authenticated:
                photo.is_favorite = False
            request.session[session_key] = False
            status = "unliked"

        photo.save()
        return JsonResponse({'success': True, 'likes': photo.likes, 'status': status})


class PhotoSlideshow(DetailView):
    """Slideshow."""
    model = Photo
    slug_url_kwarg = 'photo_slug'
    template_name = 'gallery/photo_slideshow.html'

    def get_object(self, queryset=None):
        album_slug = self.kwargs.get('album_slug')
        photo_slug = self.kwargs.get('photo_slug')
        photo = get_object_or_404(
            Photo.objects.select_related('album'),
            slug=photo_slug,
            album__slug=album_slug
        )

        if photo.slug not in self.request.session:
            photo.add_view()
            self.request.session[photo.slug] = 0

        return photo

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        current_photo = self.object
        next_photo = current_photo.get_next()

        if not next_photo:
            next_photo = Photo.objects.filter(album=current_photo.album).order_by('taken_at').first()

        context.update({
            'next_photo': next_photo,
            'liked': self.request.session.get(f"liked_{current_photo.slug}", False),
            'canonical_url': self.request.build_absolute_uri(current_photo.get_slideshow_url()),
        })

        return context