Refactor workflow routing and greeting management in Brain classes

- Update WorkflowBrain to handle greeting playback more effectively, ensuring that the initial greeting completes before transitioning to the first node.
- Introduce new methods for managing greeting states and conditions, enhancing the interaction flow for user turns.
- Refactor WorkflowLLMRouter to improve routing logic and ensure proper handling of conditional paths.
- Enhance tests to verify the correct behavior of greeting management and routing under various scenarios, including waiting for audio playback to finish.
- Update frontend components to reflect changes in edge handling and improve user experience in workflow configurations.

backend/tests/test_pipeline_events.py

@@ -4,7 +4,11 @@ import unittest
 from types import SimpleNamespace
 from unittest.mock import patch
 
-from pipecat.frames.frames import OutputTransportMessageUrgentFrame
+from pipecat.frames.frames import (
+    BotStartedSpeakingFrame,
+    BotStoppedSpeakingFrame,
+    OutputTransportMessageUrgentFrame,
+)
 from services.pipecat.pipeline_events import bind_cascade_pipeline_events
 
 
@@ -23,6 +27,18 @@ class _EventSource:
 class _Worker:
     def __init__(self):
         self.frames = []
+        self.handlers = {}
+        self.downstream_types = set()
+
+    def add_reached_downstream_filter(self, types):
+        self.downstream_types.update(types)
+
+    def event_handler(self, name):
+        def decorator(handler):
+            self.handlers[name] = handler
+            return handler
+
+        return decorator
 
     async def queue_frame(self, frame):
         self.frames.append(frame)
@@ -34,12 +50,17 @@ class _Brain:
     def __init__(self, worker):
         self.worker = worker
         self.prepared_greeting = ""
+        self.greeting_pending = False
+        self.greeting_finished = 0
 
     def prepare_greeting_context(self, greeting, _context):
         self.prepared_greeting = greeting
 
-    async def on_connected(self):
-        pass
+    async def on_connected(self, *, greeting_pending=False):
+        self.greeting_pending = greeting_pending
+
+    async def on_greeting_finished(self):
+        self.greeting_finished += 1
 
     async def on_client_ready(self):
         for content, timestamp in (
@@ -101,8 +122,46 @@ class PipelineEventTest(unittest.IsolatedAsyncioTestCase):
         )
         self.assertEqual(transcripts[0]["timestamp"], greeting_time)
         self.assertEqual(brain.prepared_greeting, "助手开场白")
+        self.assertTrue(brain.greeting_pending)
         clock.assert_called_once_with()
 
+    async def test_greeting_releases_workflow_only_after_real_playback_stop(self):
+        transport = _EventSource()
+        text_input = _EventSource()
+        user_aggregator = _EventSource()
+        assistant_aggregator = _EventSource()
+        worker = _Worker()
+        brain = _Brain(worker)
+
+        bind_cascade_pipeline_events(
+            transport=transport,
+            worker=worker,
+            brain=brain,
+            context=SimpleNamespace(),
+            text_input=text_input,
+            user_aggregator=user_aggregator,
+            assistant_aggregator=assistant_aggregator,
+            greeting="助手开场白",
+            vision_enabled=False,
+            vision_state={"client_id": None},
+        )
+
+        await transport.handlers["on_client_connected"](transport, object())
+        playback_handler = worker.handlers["on_frame_reached_downstream"]
+
+        # An unrelated stop cannot release startup until this greeting has
+        # actually produced audio.
+        await playback_handler(worker, BotStoppedSpeakingFrame())
+        self.assertEqual(brain.greeting_finished, 0)
+
+        await playback_handler(worker, BotStartedSpeakingFrame())
+        await playback_handler(worker, BotStoppedSpeakingFrame())
+        self.assertEqual(brain.greeting_finished, 1)
+
+        # Duplicate transport notifications are harmless.
+        await playback_handler(worker, BotStoppedSpeakingFrame())
+        self.assertEqual(brain.greeting_finished, 1)
+
 
 if __name__ == "__main__":
     unittest.main()