import magic
from upload.models import AbstractFile
from functools import lru_cache

@lru_cache(maxsize=128)
def get_mimetype_class_map():
    mapping = {}
    for cls in AbstractFile.__subclasses__():
        for mt in getattr(cls, 'allowed_mimetypes', []):
            mapping[mt] = cls
    return mapping


def get_mimetype(file_obj):
    mimetype = magic.from_buffer(file_obj.read(2048), mime=True)
    file_obj.seek(0)
    return mimetype


def get_upload_class_for_mimetype(mimetype):
    mimetype = mimetype.lower().replace('x-', '')  # normalisation légère
    return get_mimetype_class_map().get(mimetype)


def create_upload(request, file_obj):
    pass