from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.apps import apps
from channels.layers import get_channel_layer
from asgiref.sync import async_to_sync
from django.db import transaction
from .views import get_serializer

MODELS_TO_IGNORE = ['LogEntry', 'Session', 'ContentType', 'AdminLog', 'Permission', 'Group', 'Token', 'Phone_Otp']

def send_model_update(instance, change_type):
    """
    Hàm chung để gửi cập nhật model qua WebSocket.
    """
    model_class = instance.__class__
    model_name = model_class._meta.model_name

    if model_class.__name__ in MODELS_TO_IGNORE:
        return

    _model, serializer_class = get_serializer(model_name)
    if not serializer_class:
        print(f"Warning: No serializer found for model {model_name}. Cannot send update.")
        return

    serializer = serializer_class(instance)
    
    payload = {
        "name": model_name,
        "change_type": change_type,
        "record": serializer.data
    }

    channel_layer = get_channel_layer()
    group_name = f"model_{model_name}_updates"

    async_to_sync(channel_layer.group_send)(
        group_name,
        {
            "type": "realtime.update",
            "payload": payload
        }
    )

def generic_post_save_handler(sender, instance, created, **kwargs):
    """
    Hàm xử lý chung cho tín hiệu post_save từ BẤT KỲ model nào.
    """
    def send_update_after_commit():
        change_type = "created" if created else "updated"
        try:
            refreshed_instance = sender.objects.get(pk=instance.pk)
            send_model_update(refreshed_instance, change_type)
        except sender.DoesNotExist:
            print(f"Object {sender.__name__} {instance.pk} đã bị xóa, bỏ qua gửi update.")
            send_model_update(instance, "deleted")
        except Exception as exc:
            print(f"Lỗi trong send_update_after_commit: {exc}")

    transaction.on_commit(send_update_after_commit)

def generic_post_delete_handler(sender, instance, **kwargs):
    """
    Hàm xử lý chung cho tín hiệu post_delete từ BẤT KỲ model nào.
    """

    def send_delete_after_commit():
        send_model_update(instance, "deleted")

    transaction.on_commit(send_delete_after_commit)

def connect_signals():
    """
    Kết nối các hàm xử lý chung với tín hiệu post_save và post_delete.
    Không chỉ định `sender` để lắng nghe tất cả các model.
    """
    post_save.connect(generic_post_save_handler, dispatch_uid="generic_post_save")
    post_delete.connect(generic_post_delete_handler, dispatch_uid="generic_post_delete")

    print("Connected generic signals for real-time updates.")