from langchain_groq import ChatGroq
from langchain_openai import ChatOpenAI
import os

def get_llm(provider: str, api_key: str):
    if not api_key or not api_key.strip():
        raise ValueError("API key is missing or empty")

    provider = provider.lower()

    if provider == "groq":
        # ✅ Set env var as fallback (Groq SDK expects this sometimes)
        os.environ["GROQ_API_KEY"] = api_key

        return ChatGroq(
            model="openai/gpt-oss-120b",
            api_key=api_key,
            temperature=0
        )

    elif provider == "openai":
        return ChatOpenAI(
            model="gpt-4o-mini",
            api_key=api_key,
            temperature=0
        )

    else:
        raise ValueError(f"Unsupported LLM provider: {provider}")