from django.db.models.signals import post_save, post_delete, m2m_changed
from django.dispatch import receiver
from utils.cache import invalidate_cache_patterns
from .models import (
    PlaylistItem,
    Podcast,
    PodcastCategory,
    PodcastCollection,
    PodcastPlaylist,
    PodcastPlaylistInCollection,
)

TARGET_MODELS = [
    PodcastCategory,
    PodcastCollection,
    Podcast,
    PodcastPlaylist,
    PodcastPlaylistInCollection,
    PlaylistItem,
]


def invalidate_podcast_cache():
    """
    Invalidates all Redis cache keys for podcast API views.
    """
    return invalidate_cache_patterns("*podcast_api*", "*podcast_list*")


@receiver(post_save)
@receiver(post_delete)
def clear_podcast_cache_on_save_or_delete(sender, instance, **kwargs):
    if sender in TARGET_MODELS:
        invalidate_podcast_cache()


@receiver(m2m_changed)
def clear_podcast_cache_on_m2m(sender, instance, action, **kwargs):
    if action in ('post_add', 'post_remove', 'post_clear'):
        if isinstance(instance, (Podcast, PodcastPlaylist, PodcastCollection, PodcastCategory)):
            invalidate_podcast_cache()