from langchain_openai import ChatOpenAI
from langchain_core.messages import HumanMessage, AIMessage
from os import getenv
from dotenv import load_dotenv
from pydantic import SecretStr

load_dotenv()

def get_llm(provider: str):
    """Return a LangChain chat model for the requested provider."""
    return ChatOpenAI(
      api_key=SecretStr(getenv("OPENROUTER_API_KEY","")),
      base_url=getenv("OPENROUTER_BASE_URL"),
      model=provider,
    )

def get_messages(chats, chat_id):
    return [HumanMessage(**m) if m["role"] == "human" else AIMessage(**m) for m in chats[chat_id]]