from django.db.models import Count, Sum, Avg, Q
from django.utils import timezone
from datetime import timedelta
from .models import Product, Order, Review, CustomOrder, UserProfile

class ShopAnalytics:
    """Analytics-Klasse für Shop-Statistiken"""
    
    @staticmethod
    def get_sales_statistics(days=30):
        """Verkaufsstatistiken der letzten X Tage"""
        end_date = timezone.now()
        start_date = end_date - timedelta(days=days)
        
        orders = Order.objects.filter(
            created__range=(start_date, end_date),
            payment_status='paid'
        )
        
        return {
            'total_orders': orders.count(),
            'total_revenue': orders.aggregate(Sum('total_amount'))['total_amount__sum'] or 0,
            'average_order_value': orders.aggregate(Avg('total_amount'))['total_amount__avg'] or 0,
            'top_products': orders.values('items__product__name').annotate(
                count=Count('items__product')
            ).order_by('-count')[:5]
        }
    
    @staticmethod
    def get_product_analytics():
        """Produkt-spezifische Analytics"""
        products = Product.objects.all()
        
        return {
            'total_products': products.count(),
            'in_stock': products.filter(stock__gt=0).count(),
            'low_stock': products.filter(stock__lte=5, stock__gt=0).count(),
            'out_of_stock': products.filter(stock=0).count(),
            'featured_products': products.filter(is_featured=True).count(),
            'custom_orders': products.filter(is_custom_order=True).count(),
            'top_rated': products.annotate(
                avg_rating=Avg('reviews__rating')
            ).filter(avg_rating__gte=4.0).order_by('-avg_rating')[:5]
        }
    
    @staticmethod
    def get_user_analytics():
        """Benutzer-spezifische Analytics"""
        from django.contrib.auth.models import User
        
        users = User.objects.all()
        profiles = UserProfile.objects.all()
        
        return {
            'total_users': users.count(),
            'active_users': users.filter(last_login__gte=timezone.now() - timedelta(days=30)).count(),
            'newsletter_subscribers': profiles.filter(newsletter=True).count(),
            'top_customers': Order.objects.values('user__username').annotate(
                total_spent=Sum('total_amount')
            ).order_by('-total_spent')[:5]
        }
    
    @staticmethod
    def get_custom_order_analytics():
        """Custom Order Analytics"""
        custom_orders = CustomOrder.objects.all()
        
        return {
            'total_custom_orders': custom_orders.count(),
            'pending_orders': custom_orders.filter(status='pending').count(),
            'in_progress': custom_orders.filter(status='in_progress').count(),
            'completed': custom_orders.filter(status='completed').count(),
            'average_completion_time': custom_orders.filter(
                status='completed'
            ).aggregate(
                avg_time=Avg('updated' - 'created')
            )['avg_time']
        }
    
    @staticmethod
    def get_review_analytics():
        """Review Analytics"""
        reviews = Review.objects.all()
        
        return {
            'total_reviews': reviews.count(),
            'average_rating': reviews.aggregate(Avg('rating'))['rating__avg'] or 0,
            'rating_distribution': reviews.values('rating').annotate(
                count=Count('rating')
            ).order_by('rating'),
            'recent_reviews': reviews.order_by('-created')[:10]
        }

class UserBehaviorTracker:
    """Tracking für Benutzerverhalten"""
    
    @staticmethod
    def track_product_view(product, user=None):
        """Produktansicht tracken"""
        # Hier könnte man Redis oder eine separate Tracking-Tabelle verwenden
        pass
    
    @staticmethod
    def track_search_query(query, user=None):
        """Suchanfragen tracken"""
        pass
    
    @staticmethod
    def track_cart_addition(product, user=None):
        """Warenkorb-Hinzufügung tracken"""
        pass