import os
from django.utils.deconstruct import deconstructible

@deconstructible
class DynamicUploadTo:
    def __init__(self, prefix, field_name):
        self.prefix = prefix
        self.field_name = field_name

    def __call__(self, instance, filename):
        ext = filename.split('.')[-1]
        fname = self.field_name(instance) if callable(self.field_name) else self.field_name
        if self.prefix == "user":
            filename = f"{instance.nickname}-{fname}.{ext}"
        else:
            filename = f"{instance.id}-{fname}.{ext}"
        return os.path.join(self.prefix, filename)

def file_delete(obj, field):
    getattr(obj, field).delete(save=False)
    setattr(obj, field, None)
    obj.save(update_fields=[field])