Add proper email notifications

apps/dashboard/urls.py

@@ -7,9 +7,9 @@ app_name = "dashboard"
 urlpatterns = [
     path("", views.IndexView.as_view(), name="index"),
     path("my-prints/", views.MyPrintsView.as_view(), name="my_prints"),
+    path("p/<slug:slug>/confirm/<str:token>/", views.ConfirmEmailView.as_view(), name="confirm"),
     # Routes to be added as features land (see plan.md Section 7):
     # path("p/<slug:slug>/", views.SubmissionDetailView.as_view(), name="detail"),
     # path("p/<slug:slug>/status/", views.SubmissionStatusFragment.as_view(), name="status"),
-    # path("p/<slug:slug>/confirm/<str:token>/", views.ConfirmEmailView.as_view(), name="confirm"),
     # path("p/<slug:slug>/resend/", views.ResendConfirmationView.as_view(), name="resend"),
 ]

apps/dashboard/views.py

@@ -1,5 +1,11 @@
+import secrets
+
+from django.contrib import messages
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.db.models import Count, Q
+from django.shortcuts import get_object_or_404, redirect
+from django.utils.html import format_html
+from django.views import View
 from django.views.generic import ListView
 
 from apps.submissions.models import Submission
@@ -54,6 +60,76 @@ class IndexView(ListView):
         return ctx
 
 
+class ConfirmEmailView(View):
+    """Email-confirmation landing page (plan.md §7.4 step 8).
+
+    The URL `/p/<slug>/confirm/<token>/` is what the welcome email's button
+    points at. Hitting it does plan.md §7.3's `identifying -> processing`
+    transition (`email_confirmed = True`, `confirmation_token` cleared),
+    then bounces the user back to the dashboard with a green notice. The
+    `processing` worker (plan.md §7.5) picks the row up within ~30 s and
+    moves it to `verifying`, where it becomes visible on the public list.
+
+    Idempotent: hitting the link twice (or after expiry / approval / rejection)
+    doesn't crash -- it just surfaces a neutral "already past the
+    confirmation step" notice and redirects. Constant-time string compare
+    on the token, so a stranger guessing tokens can't sniff prefix matches
+    via response-time differences.
+    """
+
+    def get(self, request, slug, token):
+        # 404 if the row doesn't exist -- including the case where
+        # cleanup_stale has already nuked an unconfirmed submission.
+        sub = get_object_or_404(Submission, slug=slug)
+
+        if sub.status != Submission.Status.IDENTIFYING:
+            # Already past the confirmation step -- treat as a no-op rather
+            # than an error so refreshing / re-clicking is harmless.
+            messages.info(
+                request,
+                format_html(
+                    "Submission <strong class=\"font-mono\">{slug}</strong> is "
+                    "already past the confirmation step (current state: "
+                    "<em>{status}</em>). Nothing more to do.",
+                    slug=sub.slug,
+                    status=sub.get_status_display(),
+                ),
+            )
+            return redirect("dashboard:index")
+
+        # Constant-time compare on the token to make timing-side-channel
+        # attacks against the 32-byte secret impractical.
+        stored = sub.confirmation_token or ""
+        if not stored or not secrets.compare_digest(stored, token):
+            messages.error(
+                request,
+                format_html(
+                    "Couldn't confirm submission <strong class=\"font-mono\">{slug}</strong> &mdash; "
+                    "the link is invalid or has expired. If you submitted "
+                    "this print, please <a href=\"{submit_url}\" class=\"underline font-medium\">"
+                    "submit again</a>.",
+                    slug=sub.slug,
+                    submit_url="/submit/",
+                ),
+            )
+            return redirect("dashboard:index")
+
+        sub.status = Submission.Status.PROCESSING
+        sub.email_confirmed = True
+        sub.confirmation_token = ""
+        sub.save()
+
+        messages.success(
+            request,
+            format_html(
+                "Submission <strong class=\"font-mono\">{slug}</strong> confirmed! "
+                "It'll appear on the dashboard shortly, after validation.",
+                slug=sub.slug,
+            ),
+        )
+        return redirect("dashboard:index")
+
+
 class MyPrintsView(LoginRequiredMixin, ListView):
     """Private listing -- every submission the signed-in user has ever made.