# observations/signals.py

from django.db.models.signals import post_delete, post_save, pre_save
from django.dispatch import receiver
from .models import ObservationPhoto

@receiver(post_delete, sender=ObservationPhoto)
def delete_photo_file_on_delete(sender, instance, **kwargs):
    """Supprimer le fichier photo (et sa miniature) lorsqu'on supprime l'instance ObservationPhoto"""
    if instance.photo and instance.photo.storage.exists(instance.photo.name):
        instance.photo.delete(save=False)
    if instance.thumbnail and instance.thumbnail.storage.exists(instance.thumbnail.name):
        instance.thumbnail.delete(save=False)


@receiver(pre_save, sender=ObservationPhoto)
def delete_old_photo_on_change(sender, instance, **kwargs):
    """Supprimer l'ancien fichier si on remplace la photo"""
    if not instance.pk:
        return  # Nouveau fichier, pas de remplacement
    try:
        old_instance = ObservationPhoto.objects.get(pk=instance.pk)
    except ObservationPhoto.DoesNotExist:
        return
    if old_instance.photo and old_instance.photo != instance.photo:
        if old_instance.photo.storage.exists(old_instance.photo.name):
            old_instance.photo.delete(save=False)
        # Supprimer également l'ancienne miniature
        if old_instance.thumbnail and old_instance.thumbnail.storage.exists(old_instance.thumbnail.name):
            old_instance.thumbnail.delete(save=False)


@receiver(post_save, sender=ObservationPhoto)
def generate_thumbnail_on_save(sender, instance, created, **kwargs):
    """Générer la miniature après l'enregistrement d'une nouvelle photo."""
    if created and instance.photo and not instance.thumbnail:
        instance.generate_thumbnail()