from django.conf import settings
from django.contrib.auth import authenticate
from django.contrib.auth import forms as auth_forms
from django.contrib.auth import login, logout
from django.contrib.auth.decorators import login_required
from django.shortcuts import redirect, render
from django.utils.http import url_has_allowed_host_and_scheme

"""This enforces the login requirement for non-public pages using 
the decorator mechanism. 
https://www.fullstackpython.com/django-contrib-auth-decorators-login-required-examples.html
"""


class login_required_if_public(object):
    def __init__(self, f):
        if settings.PUBLIC_SITE:
            self.f = login_required(f)
        else:
            self.f = f

    def __call__(self, *args, **kwargs):
        return self.f(*args, **kwargs)


# This is copied from CUYC.cuy.website.view.auth
# If we want to do the whole online-email thing, we would also need to copy across the code in these
# imported files and delete what is superfluous.
# Or we could just load the latest version of django-registration app.
# from cuy.club.models import Member, Message
# from ..forms import WebsiteLoginForm, WebsiteRegisterForm
# from ...common import mail_site_error
# from .generic import user_is_active

"""The login and logout functions.
This is also where we would manage registration: for people wanting to create and validate their individual
logon accounts/forgottenpassword"""

############################
# Authentication Functions #
############################


def expologout(request):
    login_form = auth_forms.AuthenticationForm()
    logout(request)

    return render(request, "login/logout.html", {"form": login_form})


def expologin(request):
    # GET
    if not request.method == "POST":
        if (not request.user.is_authenticated) or (not request.user.is_active):
            return render(request, "login/index.html", {})
        else:
            # going to login page when you are already logged in
            return render(request, "tasks.html", {})

    # POST
    username = request.POST["username"]
    password = request.POST["password"]

    user = authenticate(username=username, password=password)
    if user is None:
        return render(request, "login/index.html", {"invalid": True, "username": username})
    if not user.is_active:
        return render(request, "login/enable.html", {"login_state": "notenabled"})

    try:
        login(request, user)
        # Should do the ?next= stuff here..
        return redirect_after_login(request)
    except:
        return render(request, "errors/generic.html", {})


def redirect_after_login(request):
    nxt = request.GET.get("next", None)
    if nxt is None:
        return redirect(settings.LOGIN_REDIRECT_URL)
    elif not url_has_allowed_host_and_scheme(url=nxt, allowed_hosts={request.get_host()}, require_https=request.is_secure()):
        return redirect(settings.LOGIN_REDIRECT_URL)
    else:
        return redirect(nxt)