from dataclasses import dataclass

from django.http import HttpRequest, HttpResponse, Http404
from django.shortcuts import render

from items.models import Category, Item, Subcategory


@dataclass
class SelectedCategory:
    name: str | None
    id: str | None


@dataclass
class SelectedSubcategory:
    name: str | None
    id: str | None


def index(request: HttpRequest, category: str | None = None) -> HttpResponse:
    selected_category = SelectedCategory(name=None, id=None)
    selected_subcategory = SelectedSubcategory(name=None, id=None)
    subcategories = Subcategory.objects.none()
    subcategory_slug = request.GET.get('subcategory')
    items = (
        Item.objects.select_related('category', 'subcategory')
        .prefetch_related('images')
        .order_by('category__name', 'name')
    )

    if category is None and subcategory_slug:
        raise Http404()

    if category is not None:
        try:
            cat = Category.objects.get(slug=category.lower())
            selected_category = SelectedCategory(name=cat.name, id=cat.slug)
        except Category.DoesNotExist:
            raise Http404()
        subcategories = Subcategory.objects.filter(category=cat).order_by('name')
        items = items.filter(category=cat)

        if subcategory_slug:
            try:
                subcategory_obj = subcategories.get(slug=subcategory_slug.lower())
                selected_subcategory = SelectedSubcategory(name=subcategory_obj.name, id=subcategory_obj.slug)
            except Subcategory.DoesNotExist:
                raise Http404()

            items = items.filter(subcategory=subcategory_obj)

    return render(request, 'catalog/index.html', {
        'categories': Category.objects.order_by('name'),
        'subcategories': subcategories,
        'items': items,
        'selected_category': selected_category,
        'selected_subcategory': selected_subcategory,
    })


def detail(request: HttpRequest, category: str, slug: str) -> HttpResponse:
    try:
        item = (
            Item.objects.select_related('category', 'subcategory')
            .prefetch_related('images')
            .get(category__slug=category.lower(), slug=slug)
        )
    except Item.DoesNotExist:
        raise Http404()

    images = list(item.images.all())

    return render(request, 'catalog/detail.html', {
        'categories': Category.objects.order_by('name'),
        'item': item,
        'images': images,
        'primary_image': images[0] if images else None,
    })