from django.db.models import Q, Count, F, Case, When, IntegerField
from django.db.models.functions import Concat
from.models import Product, Category
 
class ProductManager(models.Manager):
    def search_products(self, query, category=None, min_price=None, max_price=None, in_stock=None, is_featured=None):
        """Complex product search with multiple filter conditions."""
        queryset = self.get_queryset()
 
        search_query = Q(name__icontains=query) | \
                       Q(description__icontains=query) | \
                       Q(sku__iexact=query)
 
        if category:
            search_query &= Q(category__slug=category)
 
        price_query = Q()
        if min_price is not None:
            price_query &= Q(price__gte=min_price)
        if max_price is not None:
            price_query &= Q(price__lte=max_price)
 
        stock_query = Q()
        if in_stock is True:
            stock_query = Q(stock_quantity__gt=0)
        elif in_stock is False:
            stock_query = Q(stock_quantity=0)
 
        featured_query = Q(is_featured=True) if is_featured else Q()
 
        combined_query = search_query & price_query & stock_query & featured_query
 
        return queryset.filter(combined_query).select_related('category').annotate(
            category_product_count=Count('category__products'),
            discounted_price=Case(
                When(discount__gt=0, then=F('price') * (1 - F('discount') / 100)),
                default=F('price'),
                output_field=IntegerField()
            )
        ).order_by('-is_featured', '-created_at')
 
    def get_related_products(self, product, limit=5):
        """Find related products using category and tag matching."""
        return self.get_queryset().filter(
            Q(category=product.category) | Q(tags__in=product.tags.all()),
            Q(is_active=True) & ~Q(pk=product.pk)
        ).annotate(
            matching_criteria=Count('category') + Count('tags')
        ).order_by('-matching_criteria', '?')[:limit]