from __future__ import annotations

import logging

from django.core import signing
from django.core.mail import EmailMultiAlternatives
from django.http import Http404, JsonResponse
from django.shortcuts import get_object_or_404, redirect
from django.template.loader import render_to_string
from django.urls import reverse
from django.views import View

from apps.newsletter.forms import SubscriptionForm
from apps.newsletter.models import NewsletterSubscription
from apps.newsletter.services import ProviderSyncError, get_provider_service

CONFIRMATION_TOKEN_MAX_AGE_SECONDS = 60 * 60 * 24 * 2
logger = logging.getLogger(__name__)


def confirmation_token(email: str) -> str:
    return signing.dumps(email, salt="newsletter-confirm")


def send_confirmation_email(request, subscription: NewsletterSubscription) -> None:
    token = confirmation_token(subscription.email)
    confirm_url = request.build_absolute_uri(reverse("newsletter_confirm", args=[token]))
    context = {"confirmation_url": confirm_url, "subscription": subscription}
    subject = render_to_string("newsletter/email/confirmation_subject.txt", context).strip()
    text_body = render_to_string("newsletter/email/confirmation_body.txt", context)
    html_body = render_to_string("newsletter/email/confirmation_body.html", context)
    message = EmailMultiAlternatives(
        subject=subject,
        body=text_body,
        to=[subscription.email],
    )
    message.attach_alternative(html_body, "text/html")
    message.send()


class SubscribeView(View):
    def post(self, request):
        form = SubscriptionForm(request.POST)
        if not form.is_valid():
            return JsonResponse({"status": "error", "field": "email"}, status=400)
        if form.cleaned_data.get("honeypot"):
            return JsonResponse({"status": "ok"})

        email = form.cleaned_data["email"].lower().strip()
        source = form.cleaned_data.get("source") or "unknown"
        subscription, created = NewsletterSubscription.objects.get_or_create(
            email=email,
            defaults={"source": source},
        )
        if created and not subscription.confirmed:
            send_confirmation_email(request, subscription)
        return JsonResponse({"status": "ok"})


class ConfirmView(View):
    def get(self, request, token: str):
        try:
            email = signing.loads(
                token,
                salt="newsletter-confirm",
                max_age=CONFIRMATION_TOKEN_MAX_AGE_SECONDS,
            )
        except signing.BadSignature as exc:
            raise Http404 from exc
        subscription = get_object_or_404(NewsletterSubscription, email=email)
        subscription.confirmed = True
        subscription.save(update_fields=["confirmed"])
        service = get_provider_service()
        try:
            service.sync(subscription)
        except ProviderSyncError as exc:
            logger.exception("Newsletter provider sync failed: %s", exc)
        return redirect("/")