chore: Finalize cleanup phases (docstrings, utility consolidation, dev app isolation)

backend/src/ea_chatbot/api/utils.py

@@ -1,12 +1,39 @@
 from datetime import datetime, timedelta, timezone
-from typing import Optional, Any
+from typing import Optional, Any, List
 from jose import JWTError, jwt
 from pydantic import BaseModel
-from langchain_core.messages import BaseMessage
+from langchain_core.messages import BaseMessage, HumanMessage, AIMessage, SystemMessage
 from ea_chatbot.config import Settings
+from ea_chatbot.history.models import Message
 
 settings = Settings()
 
+def map_db_messages_to_langchain(db_messages: List[Message]) -> List[BaseMessage] :
+    """
+    Converts a list of database Message models to LangChain BaseMessage objects.
+    
+    Args:
+        db_messages: List of Message objects from the database.
+        
+    Returns:
+        List of HumanMessage, AIMessage, or SystemMessage objects.
+    """
+    lc_messages: List[BaseMessage] = []
+    
+    for m in db_messages:
+        role = m.role.lower()
+        if role == "user":
+            lc_messages.append(HumanMessage(content=m.content))
+        elif role == "assistant":
+            lc_messages.append(AIMessage(content=m.content))
+        elif role == "system":
+            lc_messages.append(SystemMessage(content=m.content))
+        else:
+            # Default to HumanMessage for unknown roles
+            lc_messages.append(HumanMessage(content=m.content))
+            
+    return lc_messages
+
 def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
     """
     Create a JWT access token.