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,
    Video,
    VideoCategory,
    VideoCollection,
    VideoPlaylist,
    VideoPlaylistInCollection,
)

TARGET_MODELS = [
    VideoCategory,
    VideoCollection,
    Video,
    VideoPlaylist,
    VideoPlaylistInCollection,
    PlaylistItem,
]


def invalidate_video_cache():
    """
    Invalidates all Redis cache keys for video API views.
    """
    return invalidate_cache_patterns("*video_api*", "*video_playlists*", "*video_list*")


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


@receiver(m2m_changed)
def clear_video_cache_on_m2m(sender, instance, action, **kwargs):
    if action in ('post_add', 'post_remove', 'post_clear'):
        if isinstance(instance, (Video, VideoPlaylist, VideoCollection, VideoCategory)):
            invalidate_video_cache()