items no one has ever marked can be deleted.

catalog/templates/catalog_edit.html

@@ -70,10 +70,12 @@
             </div>
             {% endif %}
 
-            {% if request.user.is_staff %}
             <div class="aside-section-wrapper">
               <div class="action-panel">
-
+                {% if item.is_deleted %}
+                <i>条目已被删除</i>
+                {% else %}
+                {% if request.user.is_staff %}
                 <div class="action-panel__label">{% trans '合并到另一条目' %} </div>
                 <div class="action-panel__button-group">
                   <form method="post" action="{% url 'catalog:merge' item.url_path item.uuid %}" onsubmit="return confirm('Confirm merging?');">
@@ -82,21 +84,21 @@
                     <input class="button" type="submit" value="{% trans '提交' %}">
                   </form>
                 </div>
-
+                {% endif %}
                 <div class="action-panel__label">{% trans '删除' %} </div>
+                {% if item.deletable or request.user.is_superuser %}
                 <div class="action-panel__button-group">
-                  <form method="post" action="{% url 'catalog:delete' item.url_path item.uuid %}" onsubmit="return confirm('Confirm deletion?');">
+                  <form method="post" action="{% url 'catalog:delete' item.url_path item.uuid %}" onsubmit="return confirm('确认删除吗？');">
                     {% csrf_token %}
                     <input class="button" type="submit" value="{% trans '提交' %}">
                   </form>
                 </div>
+                {% else %}
+                <i>条目已被用户标记过</i>
+                {% endif %}
+                {% endif %}
               </div>
-
-              {% if item.is_deteled %}
-              <!-- TODO undelete -->
-              {% endif %}
             </div>
-            {% endif %}
 
           {% endif %}
           </div>

catalog/views.py

@@ -185,9 +185,9 @@ def edit(request, item_path, item_uuid):
 def delete(request, item_path, item_uuid):
     if request.method != "POST":
         raise BadRequest()
-    if not request.user.is_staff:
-        raise PermissionDenied()
     item = get_object_or_404(Item, uid=get_uuid_or_404(item_uuid))
+    if not request.user.is_superuser and not item.deletable:
+        raise PermissionDenied()
     for res in item.external_resources.all():
         res.item = None
         res.save()

journal/models.py

@@ -1150,3 +1150,13 @@ def update_journal_for_merged_item(legacy_item_uuid):
                     f"deleted piece {p} when merging {cls.__name__}: {legacy_item} -> {new_item}"
                 )
                 p.delete()
+
+
+def journal_exists_for_item(item):
+    for cls in list(Content.__subclasses__()) + list(ListMember.__subclasses__()):
+        if cls.objects.filter(item=item).exists():
+            return False
+    return True
+
+
+Item.deletable = property(journal_exists_for_item)