fix: use textual batch update for llm chunks

Author: cristipufu

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "uipath-dev"
-version = "0.0.9"
+version = "0.0.10"
 description = "UiPath Developer Console"
 readme = { file = "README.md", content-type = "text/markdown" }
 requires-python = ">=3.11"

src/uipath/dev/ui/panels/chat_panel.py

@@ -36,12 +36,14 @@ class ChatPanel(Container):
 
     _chat_widgets: dict[str, Markdown]
     _last_update_time: dict[str, float]
+    _last_content: dict[str, str]
 
     def __init__(self, **kwargs):
         """Initialize the chat panel."""
         super().__init__(**kwargs)
         self._chat_widgets = {}
         self._last_update_time = {}
+        self._last_content = {}
 
     def compose(self) -> ComposeResult:
         """Compose the UI layout."""
@@ -52,12 +54,13 @@ def compose(self) -> ComposeResult:
                 id="chat-input",
             )
 
-    def update_messages(self, run: ExecutionRun) -> None:
+    def refresh(self, run: ExecutionRun) -> None:
         """Update the chat panel with messages from the given execution run."""
         chat_view = self.query_one("#chat-view")
         chat_view.remove_children()
         self._chat_widgets.clear()
         self._last_update_time.clear()
+        self._last_content.clear()
 
         for chat_msg in run.messages:
             self.add_chat_message(
@@ -76,7 +79,6 @@ def add_chat_message(
         chat_view = self.query_one("#chat-view")
 
         message = chat_msg.message
-
         if message is None:
             return
 
@@ -118,23 +120,45 @@ def add_chat_message(
         now = time.monotonic()
         last_update = self._last_update_time.get(message.message_id, 0.0)
 
-        if existing:
+        def should_update() -> bool:
             event = chat_msg.event
-            should_update = (
+            finished = (
                 event
                 and event.exchange
                 and event.exchange.message
                 and event.exchange.message.end is not None
             )
-            if should_update or now - last_update > 0.15:
+            # Always update when the message is finished; otherwise throttle.
+            return finished or (now - last_update > 0.15)
+
+        if existing:
+            if not should_update():
+                return
+
+            prev_content = self._last_content.get(message.message_id, "")
+
+            # Fast path: message is growing by appending new text.
+            if isinstance(existing, Markdown) and content.startswith(prev_content):
+                delta = content[len(prev_content) :]
+                if delta:
+                    # Streaming update: only append the new portion.
+                    existing.append(delta)
+            else:
+                # Fallback for non-monotonic changes: full update.
                 existing.update(content)
-                self._last_update_time[message.message_id] = now
-                if auto_scroll:
-                    chat_view.scroll_end(animate=False)
+
+            self._last_content[message.message_id] = content
+            self._last_update_time[message.message_id] = now
+
+            if auto_scroll:
+                chat_view.scroll_end(animate=False)
         else:
+            # First time we see this message: create a new widget.
             widget_instance = widget_cls(content)
             chat_view.mount(widget_instance)
             self._chat_widgets[message.message_id] = widget_instance
             self._last_update_time[message.message_id] = now
+            self._last_content[message.message_id] = content
+
             if auto_scroll:
                 chat_view.scroll_end(animate=False)

src/uipath/dev/ui/panels/run_details_panel.py

@@ -307,7 +307,7 @@ def _show_run_details(self, run: ExecutionRun):
 
     def _show_run_chat(self, run: ExecutionRun) -> None:
         chat_panel = self.query_one("#chat-panel", ChatPanel)
-        chat_panel.update_messages(run)
+        chat_panel.refresh(run)
 
     def _rebuild_spans_tree(self):
         """Rebuild the spans tree from current run's traces."""