# app/core/llm.py
import os
from dotenv import load_dotenv
from langchain_openai import AzureChatOpenAI, ChatOpenAI

# 加载.env文件中的环境变量
load_dotenv()

# 获取配置的LLM供应商
LLM_PROVIDER = os.getenv("LLM_PROVIDER", "openai").lower()

llm = None

print(f"--- [Core] Initializing LLM with provider: {LLM_PROVIDER} ---")

if LLM_PROVIDER == "azure":
    # --- Azure OpenAI 配置 ---
    required_vars = [
        "AZURE_OPENAI_ENDPOINT", "AZURE_OPENAI_API_KEY",
        "OPENAI_API_VERSION", "AZURE_OPENAI_CHAT_DEPLOYMENT_NAME"
    ]
    if not all(os.getenv(var) for var in required_vars):
        raise ValueError("One or more Azure OpenAI environment variables for chat are not set.")

    llm = AzureChatOpenAI(
        azure_endpoint=os.getenv("AZURE_OPENAI_ENDPOINT"),
        api_key=os.getenv("AZURE_OPENAI_API_KEY"),
        api_version=os.getenv("OPENAI_API_VERSION"),
        azure_deployment=os.getenv("AZURE_OPENAI_CHAT_DEPLOYMENT_NAME"),
        temperature=0,
    )

elif LLM_PROVIDER == "openai":
    # --- 标准 OpenAI 配置 ---
    if not os.getenv("OPENAI_API_KEY"):
        raise ValueError("OPENAI_API_KEY is not set for the 'openai' provider.")

    llm = ChatOpenAI(
        api_key=os.getenv("OPENAI_API_KEY"),
        model_name=os.getenv("OPENAI_MODEL_NAME", "gpt-4o"),
        temperature=0,
    )

else:
    raise ValueError(f"Unsupported LLM_PROVIDER: {LLM_PROVIDER}. Please use 'azure' or 'openai'.")