# hadith_app/signals.py

from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.core.cache import cache
from .models import * 

# 1. Define all models that affect the list
# If a Category title changes, the list must update.
# If a Status changes, the list must update.
TARGET_MODELS = [
    Hadis, HadisCategory, HadisCollection, HadisCorrection, HadisInCollection, HadisReference,
    HadisSect, HadisStatus, HadisTag, HadisTransmitter, Transmitters, TransmitterOpinion, TransmitterReliability,
    TransmitterOriginalText, ReferenceImage, BookReference, BookAttribute, BookAuthor, BookReferenceImage,
    NarratorLayer, OpinionStatus, ContentRelease
]


def invalidate_hadis_cache():
    """
    Deletes all Redis cache keys matching '*hadis_api*'.
    Falls back to cache.clear() if cache backend doesn't support delete_pattern.
    """
    try:
        if hasattr(cache, 'delete_pattern'):
            deleted = cache.delete_pattern("*hadis_api*")
            print(f"Cache cleared for hadis_api (deleted {deleted} keys)!")
        else:
            cache.clear()
            print("Cache cleared for hadis_api (fallback clear)!")
    except Exception as e:
        # Fail silently or log error, don't crash the transaction
        print(f"Cache clear failed: {e}")


@receiver(post_save)
@receiver(post_delete)
def clear_hadis_cache(sender, instance, **kwargs):
    """
    Clears the API cache whenever a Hadith or related model is saved/deleted.
    """
    if sender in TARGET_MODELS:
        invalidate_hadis_cache()
        print(f"Cache cleared for {sender.__name__} update!")