from django.utils.http import urlsafe_base64_encode, urlsafe_base64_decode
from django.shortcuts import redirect, render, get_object_or_404
from django.contrib.auth.tokens import default_token_generator
from django.contrib.sites.shortcuts import get_current_site
from django.contrib.auth.decorators import login_required
from django.contrib.auth.mixins import LoginRequiredMixin
from django.contrib.auth import logout
from django.contrib import messages
from django.template.loader import render_to_string
from django.utils.translation import gettext_lazy as _
from django.core.mail import EmailMultiAlternatives
from django.views.generic.edit import FormView
from django.utils.encoding import force_bytes
from django.http import HttpResponse, Http404
from django.conf import settings
from django.urls import reverse_lazy
from .forms import RegistrationForm, ChangePasswordForm, DeleteAccountForm
from .models import NelUser


@login_required
def settings_default(request):
    next_page = reverse_lazy('password_change')
    return redirect(next_page)


class ChangePasswordView(LoginRequiredMixin, FormView):
    template_name = 'neluser/settings/security/password.html'
    form_class = ChangePasswordForm
    success_url = reverse_lazy('password_change')

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['tab'] = 'security'
        context['active_block'] = 'password'
        return context

    def get_form_kwargs(self):
        kw = super().get_form_kwargs()
        kw['request'] = self.request
        return kw

    def form_valid(self, form):
        new_password = form.cleaned_data['new_password']
        user = self.request.user
        user.set_password(new_password)
        user.save()
        return super().form_valid(form)


class DeleteAccountView(LoginRequiredMixin, FormView):
    template_name = 'neluser/settings/security/delete_account.html'
    form_class = DeleteAccountForm
    success_url = reverse_lazy('delete_account')

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['tab'] = 'security'
        context['active_block'] = 'delete_account'
        return context

    def get_form_kwargs(self):
        kw = super().get_form_kwargs()
        kw['request'] = self.request
        return kw

    def form_valid(self, form):
        self.request.user.delete()
        logout(self.request)
        messages.info(self.request, _('Your account has been deleted.'))
        return super().form_valid(form)


def send_activation_email(request, user):
    current_site = get_current_site(request)
    context = {
        'email': user.email,
        'domain': current_site.domain,
        'site_name': current_site.name,
        'uid': urlsafe_base64_encode(force_bytes(user.pk)).decode(),
        'user': user,
        'token': default_token_generator.make_token(user),
        'protocol': 'https' if request.is_secure() else 'http',
    }
    subject = render_to_string('neluser/activate_email_subject.txt', context)
    subject = ''.join(subject.splitlines())
    email_message = EmailMultiAlternatives(
        subject,
        render_to_string('neluser/activate_email.txt', context),
        settings.DEFAULT_FROM_EMAIL,
        [user.email]
    )
    email_message.attach_alternative(
        render_to_string('neluser/activate_email.html', context),
        'text/html'
    )
    email_message.send()


def activate(request, uidb64, token):
    uid = urlsafe_base64_decode(uidb64).decode()
    user = get_object_or_404(NelUser, pk=uid)
    if default_token_generator.check_token(user, token):
        user.is_active = True
        user.save()
        return render(
            request,
            'neluser/activate_done.html'
        )
    raise Http404("Unable to activate user %d with token %s." % (uid, token))


def register(request):
    if request.method == 'GET':
        form = RegistrationForm()
    elif request.method == 'POST':
        form = RegistrationForm(data=request.POST)
        if form.is_valid():
            user = form.save(commit=False)
            user.set_password(form.cleaned_data.get('password1'))
            user.is_active = not settings.REGISTER_REQUIRE_VALIDATION
            user.save()
            if settings.REGISTER_REQUIRE_VALIDATION:
                send_activation_email(request, user)
            return render(request, 'neluser/register_done.html')
    return render(request, 'neluser/register.html', {'form': form})