#!/usr/bin/env python
# -*- coding: utf-8 -*-
from django.db import models


class ProductQuerySet(models.QuerySet):
    def sorted_in_stock_by_field(self, field):
        queryset = self.extra(select={
            'have_stock':
                'CASE WHEN (SELECT MAX(in_stock) FROM store_productvariation ' +
                'WHERE store_productvariation.product_id = store_product.id) = 0 ' +
                'THEN 0 ELSE 1 END'
        }).order_by('-have_stock', field)

        return queryset