from django.db import models
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.utils import timezone
from django.db.models import Count
from django.conf import settings

class PageView(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE, related_name='page_views')
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    
    timestamp = models.DateTimeField(auto_now_add=True, db_index=True)
    ip_address = models.GenericIPAddressField()
    user_agent = models.CharField(max_length=512, blank=True)

    class Meta:
        indexes = [
            models.Index(fields=['timestamp']),
            models.Index(fields=['content_type', 'object_id']),
        ]

    @classmethod
    def get_trending_items(cls, model_class, hours=24, limit=10):
        """Get trending items of a specific model class based on views in last X hours.
        
        Args:
            model_class: The model class to get trending items for (e.g., Park, Ride)
            hours (int): Number of hours to look back for views (default: 24)
            limit (int): Maximum number of items to return (default: 10)
        
        Returns:
            QuerySet: The trending items ordered by view count
        """
        content_type = ContentType.objects.get_for_model(model_class)
        cutoff = timezone.now() - timezone.timedelta(hours=hours)
        
        # Query through the ContentType relationship
        item_ids = cls.objects.filter(
            content_type=content_type,
            timestamp__gte=cutoff
        ).values('object_id').annotate(
            view_count=Count('id')
        ).filter(
            view_count__gt=0
        ).order_by('-view_count').values_list('object_id', flat=True)[:limit]

        # Get the actual items in the correct order
        if item_ids:
            # Convert the list to a string of comma-separated values
            id_list = list(item_ids)
            # Use Case/When to preserve the ordering
            from django.db.models import Case, When
            preserved = Case(*[When(pk=pk, then=pos) for pos, pk in enumerate(id_list)])
            return model_class.objects.filter(pk__in=id_list).order_by(preserved)
        
        return model_class.objects.none()