from django.db.models.signals import post_save, pre_save
from django.dispatch import receiver
from django.conf import settings
from django.contrib.sites.shortcuts import get_current_site
from django.core.exceptions import ObjectDoesNotExist
from .models import Order, Product, PaymentError
from .emails import (
    send_order_confirmation,
    send_order_status_update,
    send_shipping_confirmation,
    send_admin_notification,
    send_low_stock_notification
)

@receiver(post_save, sender=Order)
def handle_order_notifications(sender, instance, created, **kwargs):
    """
    Sendet E-Mail-Benachrichtigungen basierend auf Bestellstatus
    """
    if created:
        # Neue Bestellung - Admin benachrichtigen
        notification_type = 'fursuit_order' if any(p.product_type == 'fursuit' for p in instance.products.all()) else 'new_order'
        if hasattr(instance, 'customer_design') and instance.customer_design:
            notification_type = 'custom_design'
        
        send_admin_notification(None, instance, notification_type)
    
    else:
        # Status-Änderung
        try:
            old_instance = Order.objects.get(id=instance.id)
            if old_instance.status != instance.status:
                # Status hat sich geändert - Kunde benachrichtigen
                send_order_status_update(None, instance)
                
                # Bei Versand zusätzlich Versandbestätigung senden
                if instance.status == 'completed' and instance.tracking_number:
                    send_shipping_confirmation(None, instance)
        except ObjectDoesNotExist:
            pass

@receiver(post_save, sender=PaymentError)
def handle_payment_error(sender, instance, created, **kwargs):
    """
    Benachrichtigt den Admin über Zahlungsfehler
    """
    if created:
        send_admin_notification(None, instance.order, 'payment_failed', {
            'payment_error': instance
        })

@receiver(pre_save, sender=Product)
def check_stock_level(sender, instance, **kwargs):
    """
    Überprüft den Lagerbestand und sendet Benachrichtigungen bei niedrigem Stand
    """
    if not instance.pk:  # Neues Produkt
        return
    
    try:
        old_instance = Product.objects.get(pk=instance.pk)
        
        # Wenn der Lagerbestand unter den Schwellenwert fällt
        if (old_instance.stock > settings.LOW_STOCK_THRESHOLD and 
            instance.stock <= settings.LOW_STOCK_THRESHOLD):
            send_low_stock_notification(None, instance)
            
    except ObjectDoesNotExist:
        pass