Aug 5 - Update code to follow up ST - MT14c

app/models/support.py

@@ -18,6 +18,29 @@ class SupportChatSession(db.Model):
         order_by='SupportChatMessage.created_at',
     )
 
+    @property
+    def message_count(self):
+        """Number of turns in this session.
+
+        `messages` is a plain list relationship here (ST's is lazy='dynamic'),
+        so this is len() rather than .count(). It is already loaded whenever the
+        session is, so this costs no extra query.
+        """
+        return len(self.messages)
+
+    @property
+    def preview(self):
+        """First user message, for list views.
+
+        Scans the loaded list instead of ST's .filter_by(role='user').first(),
+        for the same reason. `messages` is ordered by created_at, so the first
+        match is the opening question.
+        """
+        for m in self.messages:
+            if m.role == 'user':
+                return m.content
+        return '(no messages)'
+
     def __repr__(self):
         return f'<SupportChatSession {self.id}>'