From d828ba0bc60cc62f0b8274986610c78457f7d39d Mon Sep 17 00:00:00 2001
From: Mouse Reeve <mousereeve@mouses-mbp-new.attlocal.net>
Date: Mon, 20 Nov 2023 09:56:51 -0800
Subject: [PATCH] Give admins option to test if a theme loads correctly

If a theme is uploaded incorrectly or has errors in it, users can still
select the theme but it will cause a 500 error on every page, making the
app unusable and also making it impossible for them to switch to a
functional theme.

A better fix would be to fail gracefully, but in lieu of that, this will
at least let admins confirm if a theme is broken safely.
---
 bookwyrm/migrations/0187_theme_loads.py | 18 +++++++++++
 bookwyrm/models/site.py                 |  1 +
 bookwyrm/templates/settings/themes.html | 43 +++++++++++++++++++++++++
 bookwyrm/urls.py                        |  5 +++
 bookwyrm/views/__init__.py              |  2 +-
 bookwyrm/views/admin/themes.py          | 20 ++++++++++++
 6 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 bookwyrm/migrations/0187_theme_loads.py

diff --git a/bookwyrm/migrations/0187_theme_loads.py b/bookwyrm/migrations/0187_theme_loads.py
new file mode 100644
index 000000000..3649c991c
--- /dev/null
+++ b/bookwyrm/migrations/0187_theme_loads.py
@@ -0,0 +1,18 @@
+# Generated by Django 3.2.23 on 2023-11-20 17:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("bookwyrm", "0186_invite_request_notification"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="theme",
+            name="loads",
+            field=models.BooleanField(blank=True, null=True),
+        ),
+    ]
diff --git a/bookwyrm/models/site.py b/bookwyrm/models/site.py
index a27c4b70d..b962d597b 100644
--- a/bookwyrm/models/site.py
+++ b/bookwyrm/models/site.py
@@ -149,6 +149,7 @@ class Theme(SiteModel):
     created_date = models.DateTimeField(auto_now_add=True)
     name = models.CharField(max_length=50, unique=True)
     path = models.CharField(max_length=50, unique=True)
+    loads = models.BooleanField(null=True, blank=True)
 
     def __str__(self):
         # pylint: disable=invalid-str-returned
diff --git a/bookwyrm/templates/settings/themes.html b/bookwyrm/templates/settings/themes.html
index d27aeb0ce..c077fa5e3 100644
--- a/bookwyrm/templates/settings/themes.html
+++ b/bookwyrm/templates/settings/themes.html
@@ -12,6 +12,15 @@
 {% endblock %}
 
 {% block panel %}
+{% if broken_theme %}
+<div class="notification is-danger">
+    <span class="icon icon-warning" aria-hidden="true"></span>
+    <span>
+        {% trans "One of your themes appears to be broken. Selecting this theme will make the application unusable." %}
+    </span>
+</div>
+{% endif %}
+
 {% if success %}
 <div class="notification is-success is-light">
     <span class="icon icon-check" aria-hidden="true"></span>
@@ -98,6 +107,9 @@
                 <th>
                     {% trans "Actions" %}
                 </th>
+                <th>
+                    {% trans "Status" %}
+                </th>
             </tr>
             {% for theme in themes %}
             <tr>
@@ -112,6 +124,37 @@
                         </button>
                     </form>
                 </td>
+                <td>
+                {% if theme.loads is None %}
+
+                    <form method="POST" action="{% url 'settings-themes-test' theme.id %}">
+                        {% csrf_token %}
+                        <button type="submit" class="button is-small">
+                            <span class="icon icon-question-circle" aria-hidden="true"></span>
+                            <span>{% trans "Test theme" %}</span>
+                        </button>
+                    </form>
+
+                {% elif not theme.loads %}
+
+                    <span class="tag is-danger">
+                        <span class="icon icon-warning" aria-hidden="true"></span>
+                        <span>
+                            {% trans "Broken theme" %}
+                        </span>
+                    </span>
+
+                {% else %}
+
+                    <span class="tag is-success">
+                        <span class="icon icon-check" aria-hidden="true"></span>
+                        <span>
+                            {% trans "Loaded successfully" %}
+                        </span>
+                    </span>
+
+                {% endif %}
+                </td>
             </tr>
             {% endfor %}
         </table>
diff --git a/bookwyrm/urls.py b/bookwyrm/urls.py
index 8541f4fb6..233e7786e 100644
--- a/bookwyrm/urls.py
+++ b/bookwyrm/urls.py
@@ -109,6 +109,11 @@ urlpatterns = [
         views.delete_theme,
         name="settings-themes-delete",
     ),
+    re_path(
+        r"^settings/themes/(?P<theme_id>\d+)/test/?$",
+        views.test_theme,
+        name="settings-themes-test",
+    ),
     re_path(
         r"^settings/announcements/?$",
         views.Announcements.as_view(),
diff --git a/bookwyrm/views/__init__.py b/bookwyrm/views/__init__.py
index 2d2e97f52..4d298617c 100644
--- a/bookwyrm/views/__init__.py
+++ b/bookwyrm/views/__init__.py
@@ -30,7 +30,7 @@ from .admin.reports import (
     moderator_delete_user,
 )
 from .admin.site import Site, Registration, RegistrationLimited
-from .admin.themes import Themes, delete_theme
+from .admin.themes import Themes, delete_theme, test_theme
 from .admin.user_admin import UserAdmin, UserAdminList, ActivateUserAdmin
 
 # user preferences
diff --git a/bookwyrm/views/admin/themes.py b/bookwyrm/views/admin/themes.py
index 5658d243a..284a90833 100644
--- a/bookwyrm/views/admin/themes.py
+++ b/bookwyrm/views/admin/themes.py
@@ -6,6 +6,8 @@ from django.utils.decorators import method_decorator
 from django.views import View
 from django.views.decorators.http import require_POST
 
+from sass_processor.processor import sass_processor
+
 from bookwyrm import forms, models
 
 
@@ -40,6 +42,7 @@ class Themes(View):
 def get_view_data():
     """data for view"""
     return {
+        "broken_theme": models.Theme.objects.filter(loads=False).exists(),
         "themes": models.Theme.objects.all(),
         "theme_form": forms.ThemeForm(),
     }
@@ -52,3 +55,20 @@ def delete_theme(request, theme_id):
     """Remove a theme"""
     get_object_or_404(models.Theme, id=theme_id).delete()
     return redirect("settings-themes")
+
+
+@require_POST
+@permission_required("bookwyrm.system_administration", raise_exception=True)
+# pylint: disable=unused-argument
+def test_theme(request, theme_id):
+    """Remove a theme"""
+    theme = get_object_or_404(models.Theme, id=theme_id)
+
+    try:
+        sass_processor(theme.path)
+        theme.loads = True
+    except Exception:  # pylint: disable=broad-except
+        theme.loads = False
+
+    theme.save()
+    return redirect("settings-themes")