from django.utils import translation


class UserLocaleMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        language = None
        activated = False
        user = getattr(request, "user", None)
        if user and getattr(user, "is_authenticated", False):
            language = getattr(user, "preferred_language", None)
            if language:
                translation.activate(language)
                request.LANGUAGE_CODE = language
                activated = True

        response = self.get_response(request)

        active_language = translation.get_language()
        if active_language:
            response["Content-Language"] = active_language

        if activated:
            translation.deactivate()

        return response