from typing import Optional
from langchain_openai import ChatOpenAI
from config import Config


def create_chat_model(model_section: Optional[str] = None) -> ChatOpenAI:
    """创建 LLM 实例"""
    model_config = Config.get_model_config(model_section)
    return ChatOpenAI(
        model=model_config['model'],
        api_key=model_config['api_key'],
        base_url=model_config.get('base_url'),
        temperature=0.1,
        max_retries=Config.MAX_RETRIES,
        timeout=Config.TIMEOUT
    )