Improve the UX on email management

The most-frequent actions exposed on this UI make no sense:

- You can't make the only email primary (it already is)
- You can't remove your only email
- Re-sending email to a verified email does nothing

Let's try to mediate this a bit by just controlling what buttons are
available for end users. This is a simple display-only fix that doesn't
require any changes to the `django-allauth` backend.

ws/templates/account/email.html

@@ -1,5 +1,6 @@
 {% extends "base.html" %}
 {% load crispy_forms_tags %}
+{% load email_tags %}
 
 {% block head_title %}Emails{% endblock %}
 
@@ -33,9 +34,41 @@ <h3>E-mail Addresses</h3>
       </div>
 
       <div class="btn-group" role="group">
-        <button class="btn btn-default" type="submit" name="action_primary">Make Primary</button>
-        <button class="btn btn-default" type="submit" name="action_send">Re-send Verification</button>
-        <button class="btn btn-default" type="submit" name="action_remove">Remove</button>
+        {# Disable if there's only one email #}
+        {# Always display the button to self-document multi-email support #}
+        <button
+          class="btn btn-default"
+          type="submit"
+          {% if user.emailaddress_set.all|length < 2 %}
+          disabled
+          title="Email address is already primary."
+          {% endif %}
+          name="action_primary">
+            Make Primary
+        </button>
+
+        {# Without using JavaScript, there's no way to disable this per-email #}
+        {# But we can handle the usual case of *all* emails being verified #}
+        {% if user.emailaddress_set.all|has_unverified_email %}
+          <button
+            class="btn btn-default"
+            type="submit"
+            name="action_send">
+              Re-send Verification
+          </button>
+        {% endif %}
+
+        {# Always display the button to self-document multi-email support #}
+        <button
+          class="btn btn-default"
+          type="submit"
+          {% if user.emailaddress_set.all|length < 2 %}
+          disabled
+          title="Cannot remove your only email address."
+          {% endif %}
+          name="action_remove">
+            Remove
+        </button>
       </div>
     </form>
 

ws/templatetags/email_tags.py

@@ -1,11 +1,19 @@
+from allauth.account.models import EmailAddress
 from django import template
+from django.db.models import QuerySet
 
 from ws import enums
+from ws.models import Trip
 
 register = template.Library()
 
 
-def _conditional_rendering(trip):
+@register.filter
+def has_unverified_email(emails: QuerySet[EmailAddress]) -> bool:
+    return any(not email.verified for email in emails)
+
+
+def _conditional_rendering(trip: Trip) -> dict[str, bool]:
     return {
         "show_program": trip.program_enum != enums.Program.NONE,
         "show_trip_type": trip.trip_type_enum != enums.TripType.NONE,

ws/tests/views/test_account.py

@@ -270,3 +270,163 @@ def test_attempt_changing_to_insecure_password(self):
         form_group = soup.find(class_="has-error")
         self.assertTrue(form_group)
         self.assertTrue(form_group.find(string="This password is too common."))
+
+
+class ManageEmailsTest(TestCase):
+    maxDiff = None
+
+    def _get_buttons(self, user):
+        self.client.force_login(user)
+        response = self.client.get("/accounts/email/")
+        soup = BeautifulSoup(response.content, "html.parser")
+        form = soup.find("form", action="/accounts/email/")
+        return {btn.text.strip(): btn.attrs for btn in form.find_all("button")}
+
+    def test_one_primary_email(self):
+        """Test the usual case -- just one verified primary email."""
+        user = factories.UserFactory(
+            emailaddress__primary=True,
+            emailaddress__verified=True,
+        )
+
+        self.assertEqual(
+            self._get_buttons(user),
+            {
+                "Make Primary": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "disabled": "",
+                    "title": "Email address is already primary.",
+                    "name": "action_primary",
+                },
+                # Notably "Re-send Verification" is missing entirely
+                "Remove": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "disabled": "",
+                    "title": "Cannot remove your only email address.",
+                    "name": "action_remove",
+                },
+            },
+        )
+
+    def test_one_unverified_email(self):
+        user = factories.UserFactory(emailaddress__verified=False)
+
+        self.assertEqual(
+            self._get_buttons(user),
+            {
+                "Make Primary": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "disabled": "",
+                    "title": "Email address is already primary.",
+                    "name": "action_primary",
+                },
+                "Re-send Verification": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_send",
+                },
+                "Remove": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "disabled": "",
+                    "title": "Cannot remove your only email address.",
+                    "name": "action_remove",
+                },
+            },
+        )
+
+    def test_two_verified_emails(self):
+        """With two emails, we can remove either or make either primary."""
+        user = factories.UserFactory()
+        factories.EmailAddressFactory(
+            user=user,
+            email="[email protected]",
+            primary=False,
+            verified=True,
+        )
+
+        self.assertEqual(
+            self._get_buttons(user),
+            {
+                "Make Primary": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_primary",
+                },
+                # Notably "Re-send Verification" is missing entirely -- both are verified!
+                "Remove": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_remove",
+                },
+            },
+        )
+
+    def test_two_emails_but_one_unverified(self):
+        """Test the case of a newly-added but still unverified email."""
+        user = factories.UserFactory(
+            emailaddress__verified=True,
+        )
+        factories.EmailAddressFactory(
+            user=user,
+            email="[email protected]",
+            primary=False,
+            verified=False,
+        )
+
+        self.assertEqual(
+            self._get_buttons(user),
+            {
+                "Make Primary": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_primary",
+                },
+                # Because there's at least one unverified email, we allow re-sending
+                "Re-send Verification": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_send",
+                },
+                "Remove": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_remove",
+                },
+            },
+        )
+
+    def test_multiple_unverified(self):
+        """You can still add an email even if one is unverified!"""
+        user = factories.UserFactory()
+        factories.EmailAddressFactory(
+            user=user,
+            email="[email protected]",
+            primary=False,
+            verified=False,
+        )
+
+        self.assertEqual(
+            self._get_buttons(user),
+            {
+                "Make Primary": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_primary",
+                },
+                # Because there's at least one unverified email, we allow re-sending
+                "Re-send Verification": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_send",
+                },
+                "Remove": {
+                    "class": ["btn", "btn-default"],
+                    "type": "submit",
+                    "name": "action_remove",
+                },
+            },
+        )