from functools import cache

from langchain_openai import ChatOpenAI

from app.config import settings


@cache
def get_llm() -> ChatOpenAI:
    if not settings.llm_api_key.strip() or not settings.llm_model.strip():
        raise ValueError("未配置 LLM_API_KEY 或 LLM_MODEL")
    return ChatOpenAI(
        model=settings.llm_model,
        api_key=settings.llm_api_key,
        base_url=settings.llm_base_url,
        timeout=settings.llm_timeout,
        max_retries=settings.llm_max_retries,
    )