from django.contrib import messages
from django.contrib.auth.signals import user_logged_in
from django.core.urlresolvers import reverse
from django.dispatch import receiver
from django.utils.safestring import mark_safe
from django.utils.translation import ugettext as _

from .utils import get_kfet_generic_user


@receiver(user_logged_in)
def suggest_auth_generic(sender, request, user, **kwargs):
    """
    Suggest logged in user to continue as the kfet generic user.

    Message is only added if the following conditions are met:
    - the next page (where user is going to be redirected due to successful
        authentication) is related to kfet, i.e. 'k-fet' is in its url.
    - logged in user is a kfet staff member (except the generic user).
    """
    # Filter against the next page.
    if not(hasattr(request, 'GET') and 'next' in request.GET):
        return

    next_page = request.GET['next']
    generic_url = reverse('kfet.login.generic')

    if not('k-fet' in next_page and not next_page.startswith(generic_url)):
        return

    # Filter against the logged in user.
    if not(user.has_perm('kfet.is_team') and user != get_kfet_generic_user()):
        return

    # Seems legit to add message.
    text = _("K-Fêt — Ouvrir une session partagée ?")
    messages.info(request, mark_safe(
        '<a href="#" data-url="{}" onclick="submit_url(this)">{}</a>'
        .format(generic_url, text)
    ))