import logging

from django.forms import ModelForm
from django.views.decorators.csrf import csrf_exempt
from django.shortcuts import render

from .models import Unsubscription

logger = logging.getLogger(__name__)

class UnsubscribeForm(ModelForm):
    class Meta:
        model = Unsubscription
        fields = ['email', 'mailout']


@csrf_exempt  # Submitted directly by Gmail and similar - no CSRF token.
def unsubscribe(request):
    """Endpoint for use with Gmail one-click unsubscribe or similar.

    Gmail now requires "List-Unsubscribe" headers for senders over a certain
    monthly volume (currently 5000 emails). Add the following headers to your
    mailout:

        List-Unsubscribe: <https://sfconservancy.org/contacts/unsubscribe/?email=foo@bar.com&mailout=jan2024-news>
        List-Unsubscribe-Post: List-Unsubscribe=One-Click

    Interfaces like Gmail will then provide a user interface to unsubscribe
    which will hit this endpoint.

    Our understanding is that Gmail will submit the form with and HTTP POST request, but
    with GET-style URL parameters. Hence this feature has been built to work both with
    GET and POST-style data as well as GET and POST methods, just in case. Test it like
    this:

    curl -X POST -d 'email=foo@bar.com&mailout=jan2024-new' https://sfconservancy.org/contacts/unsubscribe/
    curl -X POST 'https://sfconservancy.org/contacts/unsubscribe/?email=foo@bar.com&mailout=jan2024-new'

    Or visit in a browser:

    https://sfconservancy.org/contacts/unsubscribe/?email=foo@bar.com&mailout=jan2024-new
    """
    if request.method == 'POST':
        logger.debug('Unsubscribe GET: %s', request.GET)
        logger.debug('Unsubscribe POST: %s', request.POST)
        form = UnsubscribeForm(request.GET.dict() | request.POST.dict())
        if form.is_valid():
            form.save()
            logger.info('Unsubscribed %s', form.cleaned_data['email'])
            return render(request, 'contacts/unsubscribe_success.html')
    else:
        form = UnsubscribeForm(request.GET.dict() | request.POST.dict())
    return render(request, 'contacts/unsubscribe.html', {'form': form})