from django.shortcuts import redirect

from django.conf import settings

from urllib.parse import urlencode

from re import compile

EXEMPT_URLS = [compile(settings.LOGIN_URL.lstrip('/'))]

if hasattr(settings, 'LOGIN_EXEMPT_URLS'):

    EXEMPT_URLS += [compile(expr) for expr in settings.LOGIN_EXEMPT_URLS]

class MtdcLoginRequiredWithContextMiddleware:

    """

    Middleware intended to emulate login_required decorator so we can forward the context query arg

    """

    def process_request(self, request):

        if not request.user.is_authenticated():

            path = request.path_info.lstrip('/')

            if not any(m.match(path) for m in EXEMPT_URLS):

                if request.GET.get("context", ""):

                    context = request.GET["context"]

                    response = redirect(settings.LOGIN_URL)

                    response["LOCATION"] += "?"+urlencode({"context": context, "next": "/"+path})

                    return response