urlpatterns = [
    path('', views.products_list, name='product_list'),
    path('<str:category_slug/>', views.products_list_by_category, name='product_list_by_category'),
    path('<str:category_slug/<str:slug>/', views.products_detail, name='product_detail'),
]

def products_list_by_category(request, category_slug):
    template_name = 'products/product-list.html'
    products_list = Product.objects.filter(category__slug=category_slug).order_by('price')
    categories = Category.objects.all()
    product_filter = ProductFilter(request.GET, queryset=products_list)
    products_list = product_filter.qs
    quantity = products_list.count()

    if products_list:
        min_price = products_list.first().price
        max_price = products_list.last().price

    paginator = Paginator(products_list, 16)
    page = request.GET.get('page')

    try:
        products = paginator.page(page)
    except PageNotAnInteger:
        products = paginator.page(1)
    except EmptyPage:
        products = paginator.page(paginator.num_pages)

    context = { 'products': products,
                'categories': categories,
                'product_filter': product_filter,
                'quantity': quantity,
                }

    if products_list:
        context['max_price'] = max_price
        context['min_price'] = min_price

    return render(request, template_name, context)