from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.http import HttpRequest, HttpResponse, JsonResponse
from django.shortcuts import get_object_or_404, redirect, render
from django.urls import reverse
from django.utils.http import url_has_allowed_host_and_scheme
from django.views.decorators.http import require_POST

from favorites.models import Favorite
from items.models import Item


def wants_json_response(request: HttpRequest) -> bool:
    return (
        request.headers.get("x-requested-with") == "XMLHttpRequest"
        or "application/json" in request.headers.get("accept", "")
    )


@login_required
def index(request: HttpRequest) -> HttpResponse:
    favorite_records = (
        Favorite.objects.filter(user=request.user)
        .select_related("item__category", "item__subcategory")
        .prefetch_related("item__images")
        .order_by("-created_at", "-id")
    )
    items = [favorite.item for favorite in favorite_records]

    return render(request, "favorites/index.html", {
        "items": items,
        "favorite_count": len(items),
        "favorite_item_ids": {item.id for item in items},
    })


@login_required
@require_POST
def toggle(request: HttpRequest) -> HttpResponse:
    item_id = request.POST.get("item_id")
    item = get_object_or_404(Item, pk=item_id)

    favorite = Favorite.objects.filter(user=request.user, item=item).first()
    if favorite:
        favorite.delete()
        is_favorite = False
        message = f"Товар «{item.name}» удалён из избранного."
    else:
        Favorite.objects.create(user=request.user, item=item)
        is_favorite = True
        message = f"Товар «{item.name}» добавлен в избранное."

    favorite_count = Favorite.objects.filter(user=request.user).count()
    next_url = request.POST.get("next") or reverse("favorites:index")

    if wants_json_response(request):
        return JsonResponse({
            "item_id": item.pk,
            "is_favorite": is_favorite,
            "favorite_count": favorite_count,
            "message": message,
        })

    messages.success(request, message)

    if not url_has_allowed_host_and_scheme(
        next_url,
        allowed_hosts={request.get_host()},
        require_https=request.is_secure(),
    ):
        next_url = reverse("favorites:index")

    return redirect(next_url)