"""
The common views of the different organisations.
- Authentication
- Profile edition
"""

from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.contrib.auth.models import User
from django.contrib.auth.views import (
    login as django_login, logout as django_logout
)
from django.http import HttpResponseBadRequest
from django.shortcuts import render, redirect, get_object_or_404
from django.utils.translation import ugettext_lazy as _
from django.views.generic import TemplateView

from .forms import (
    ProfileForm, UserForm, UserRegistrationForm, ProfileRegistrationForm
)
from .shared import get_or_create_clipper


# ---
# Authentcation
# ---

def login(request):
    if request.user.is_authenticated():
        return redirect("home")
    context = {}
    # Fetch the next page from the request data
    if request.method == "GET" and 'next' in request.GET:
        context['next'] = request.GET['next']
    return render(request, "gestion/login_switch.html", context)


def login_ext(request):
    if request.method == "POST" and "username" in request.POST:
        try:
            user = User.objects.get(username=request.POST["username"])
            if user.profile.login_clipper:
                return render(request, "gestion/error.html",
                              {"error_type": "use_clipper_login"})
            if not user.has_usable_password() or user.password in ("", "!"):
                return render(request, "gestion/error.html",
                              {"error_type": "no_password"})
        except User.DoesNotExist:
            pass
    context = {}
    # Fetch the next page from the request data
    if request.method == "GET" and 'next' in request.GET:
        context['next'] = request.GET['next']
    if request.method == "POST" and 'next' in request.POST:
        context['next'] = request.POST['next']
    return django_login(request, template_name='gestion/login.html',
                        extra_context=context)


@login_required
def logout(request):
    if request.user.profile.login_clipper:
        return redirect("gestion:cas_logout")
    else:
        return django_logout(request)


# ---
# User management
# ---

@login_required
def profile(request):
    success = False
    user = request.user
    if request.method == "POST":
        user_form = UserForm(request.POST, instance=user)
        profile_form = ProfileForm(request.POST, instance=user.profile)
        if (user_form.is_valid() and profile_form.is_valid()):
            user_form.save()
            profile_form.save()
            success = True
    else:
        user_form = UserForm(instance=user)
        profile_form = ProfileForm(instance=user.profile)
    return render(request, "gestion/profile.html",
                  {"user_form": user_form, "profile_form": profile_form,
                   "success": success})


# TODO: send "Welcome" email
class RegistrationView(TemplateView):
    user = None
    form_class = None
    form_only = False  # TODO: explain this
    page_url = ""  # TODO: explain this

    def get_form_kwargs(self, **kwargs):
        return kwargs

    # ---
    # Template related code
    # ---

    @property
    def template_name(self):
        if self.form_only:
            return "gestion/registration_form.html"
        else:
            return "gestion/registration.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)

        post_data = kwargs.pop("post_data", None)
        user = self.user
        context["user"] = user
        context["page_url"] = self.page_url
        context["user_form"] = UserRegistrationForm(
            instance=user,
            prefix="user",
            data=post_data
        )
        context["profile_form"] = ProfileRegistrationForm(
            instance=user.profile if user else None,
            prefix="profile",
            data=post_data
        )
        context["extra_form"] = self.form_class(**self.get_form_kwargs(
            prefix="extra",
            data=post_data,
        ))
        return context

    # ---
    # Request processing
    # ---

    def get(self, request, username=""):
        """
        The `user_type` GET parameter is used the following way:
        - If not set, return empty forms.
        - If set to "normal", assume the user exists.
        - If set to, "clipper" create a user linked to a clipper account if a
          user with the provided username doesn't exist.

        The `fullname` GET parameter is only used to create new clipper users
        """
        user_type, fullname = self.clean_GET(request.GET)
        if user_type == "clipper":
            self.user, _ = get_or_create_clipper(username, fullname)
        elif user_type == "normal":
            self.user = get_object_or_404(User, username=username)

        context = self.get_context_data()
        return super().render_to_response(context)

    def post(self, request):
        # the `user_exists` POST parameter indicates that we should expect the
        # user to be in the database already. Otherwise we return a 404 page.
        # TODO: 404 is bad, prefer an "displayable" error
        if "user_exists" in request.POST:
            username = request.POST.get("user-username", "")
            self.user = get_object_or_404(User, username=username)
        context = self.get_context_data(
            post_data=request.POST,
        )
        if all([context["user_form"].is_valid(),
                context["profile_form"].is_valid(),
                context["extra_form"].is_valid()]):
            self.user = context["user_form"].save()
            context["user"] = self.user
            context["profile_form"].save()
            context["extra_form"].save()
            messages.success(
                request,
                _("L'inscription de %(fullname)s (<tt>%(username)s</tt>)"
                  " a été enregistrée avec succès")
                % {"fullname": self.user.get_full_name(),
                   "username": self.user.username}
            )
        return super().render_to_response(context)

    @staticmethod
    def clean_GET(get_params):
        allowed_user_types = {"normal", "clipper", None}
        user_type = get_params.get("user_type")
        if user_type not in allowed_user_types:
            return HttpResponseBadRequest(
                "Invalid value `{}` expected `({})`"
                .format(user_type, "|".join(allowed_user_types))
            )
        fullname = get_params.get("fullname")
        if fullname is not None:
            fullname = str(fullname)
        return user_type, fullname