fix(api): Robustly handle complex LangChain message content in API responses and persistence

tests/api/test_utils.py

@@ -1,5 +1,6 @@
 from datetime import timedelta
-from ea_chatbot.api.utils import create_access_token, decode_access_token
+from ea_chatbot.api.utils import create_access_token, decode_access_token, convert_to_json_compatible
+from langchain_core.messages import AIMessage
 
 def test_create_and_decode_access_token():
     """Test that a token can be created and then decoded."""
@@ -22,3 +23,29 @@ def test_expired_token():
     token = create_access_token(data, expires_delta=timedelta(minutes=-1))
     
     assert decode_access_token(token) is None
+
+def test_convert_to_json_compatible_complex_message():
+    """Test that list-based message content is handled correctly."""
+    # Mock a message with list-based content (blocks)
+    msg = AIMessage(content=[
+        {"type": "text", "text": "Hello "},
+        {"type": "text", "text": "world!"},
+        {"type": "other", "data": "ignore me"}
+    ])
+    
+    result = convert_to_json_compatible(msg)
+    assert result["content"] == "Hello world!"
+    assert result["type"] == "ai"
+
+def test_convert_to_json_compatible_message_with_text_prop():
+    """Test that .text property is prioritized if available."""
+    # Using a MagicMock to simulate the property safely
+    from unittest.mock import MagicMock
+    msg = MagicMock(spec=AIMessage)
+    msg.content = "Raw content"
+    msg.text = "Just the text"
+    msg.type = "ai"
+    msg.additional_kwargs = {}
+    
+    result = convert_to_json_compatible(msg)
+    assert result["content"] == "Just the text"