import os

def dynamic_upload_to(prefix, field_name_func):
    def wrapper(instance, filename):
        ext = filename.split('.')[-1]
        field_name = field_name_func(instance)

        if prefix == 'user':
            filename = f'{instance.nickname}-{field_name}.{ext}'
        else:
            filename = f'{instance.id}-{field_name}.{ext}'

        return os.path.join(prefix, filename)
    
    return wrapper

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