fix(feishu): support @bot message in topic groups (#1206)

* fix(feishu): support @bot message in topic groups

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* fix(feishu): preserve rich-text formatting and add parser unit tests

* chore(test): remove unused import to fix ruff lint error

* style: auto-format imports to satisfy ruff

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/app/channels/feishu.py

@@ -466,7 +466,33 @@ class FeishuChannel(Channel):
 
             # Parse message content
             content = json.loads(message.content)
-            text = content.get("text", "").strip()
+            
+            if "text" in content:
+                # Handle plain text messages
+                text = content["text"]
+            elif "content" in content and isinstance(content["content"], list):
+                # Handle rich-text messages with a top-level "content" list (e.g., topic groups/posts)
+                text_paragraphs: list[str] = []
+                for paragraph in content["content"]:
+                    if isinstance(paragraph, list):
+                        paragraph_text_parts: list[str] = []
+                        for element in paragraph:
+                            if isinstance(element, dict):
+                                # Include both normal text and @ mentions
+                                if element.get("tag") in ("text", "at"):
+                                    text_value = element.get("text", "")
+                                    if text_value:
+                                        paragraph_text_parts.append(text_value)
+                        if paragraph_text_parts:
+                            # Join text segments within a paragraph with spaces to avoid "helloworld"
+                            text_paragraphs.append(" ".join(paragraph_text_parts))
+                
+                # Join paragraphs with blank lines to preserve paragraph boundaries
+                text = "\n\n".join(text_paragraphs)
+            else:
+                text = ""
+            text = text.strip()
+            
             logger.info(
                 "[Feishu] parsed message: chat_id=%s, msg_id=%s, root_id=%s, sender=%s, text=%r",
                 chat_id,

backend/tests/test_feishu_parser.py

@@ -0,0 +1,81 @@
+import json
+from unittest.mock import MagicMock
+
+import pytest
+
+from app.channels.feishu import FeishuChannel
+from app.channels.message_bus import MessageBus
+
+
+def test_feishu_on_message_plain_text():
+    bus = MessageBus()
+    config = {"app_id": "test", "app_secret": "test"}
+    channel = FeishuChannel(bus, config)
+
+    # Create mock event
+    event = MagicMock()
+    event.event.message.chat_id = "chat_1"
+    event.event.message.message_id = "msg_1"
+    event.event.message.root_id = None
+    event.event.sender.sender_id.open_id = "user_1"
+    
+    # Plain text content
+    content_dict = {"text": "Hello world"}
+    event.event.message.content = json.dumps(content_dict)
+
+    # Call _on_message
+    channel._on_message(event)
+
+    # Since main_loop isn't running in this synchronous test, we can't easily assert on bus,
+    # but we can intercept _make_inbound to check the parsed text.
+    with pytest.MonkeyPatch.context() as m:
+        mock_make_inbound = MagicMock()
+        m.setattr(channel, "_make_inbound", mock_make_inbound)
+        channel._on_message(event)
+        
+        mock_make_inbound.assert_called_once()
+        assert mock_make_inbound.call_args[1]["text"] == "Hello world"
+
+
+def test_feishu_on_message_rich_text():
+    bus = MessageBus()
+    config = {"app_id": "test", "app_secret": "test"}
+    channel = FeishuChannel(bus, config)
+
+    # Create mock event
+    event = MagicMock()
+    event.event.message.chat_id = "chat_1"
+    event.event.message.message_id = "msg_1"
+    event.event.message.root_id = None
+    event.event.sender.sender_id.open_id = "user_1"
+    
+    # Rich text content (topic group / post)
+    content_dict = {
+        "content": [
+            [
+                {"tag": "text", "text": "Paragraph 1, part 1."},
+                {"tag": "text", "text": "Paragraph 1, part 2."}
+            ],
+            [
+                {"tag": "at", "text": "@bot"},
+                {"tag": "text", "text": " Paragraph 2."}
+            ]
+        ]
+    }
+    event.event.message.content = json.dumps(content_dict)
+
+    with pytest.MonkeyPatch.context() as m:
+        mock_make_inbound = MagicMock()
+        m.setattr(channel, "_make_inbound", mock_make_inbound)
+        channel._on_message(event)
+        
+        mock_make_inbound.assert_called_once()
+        parsed_text = mock_make_inbound.call_args[1]["text"]
+        
+        # Expected text:
+        # Paragraph 1, part 1. Paragraph 1, part 2.
+        # 
+        # @bot  Paragraph 2.
+        assert "Paragraph 1, part 1. Paragraph 1, part 2." in parsed_text
+        assert "@bot  Paragraph 2." in parsed_text
+        assert "\n\n" in parsed_text