# File: backend/app/main.py (Update - Add startup event)
# Description: FastAPI 应用入口 (添加数据库初始化)

from fastapi import FastAPI
from starlette.middleware.cors import CORSMiddleware
from app.api.v1.api import api_router as api_router_v1
import app.core.config # Ensure config is loaded
from app.db.database import create_db_and_tables # Import table creation function
from contextlib import asynccontextmanager

# --- Lifespan context manager for startup/shutdown events ---
@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup actions
    print("应用程序启动中...")
    await create_db_and_tables() # Create database tables on startup
    print("数据库表已检查/创建。")
    # You can add the default assistant creation here if needed,
    # but doing it in the service/model definition might be simpler for defaults.
    yield
    # Shutdown actions
    print("应用程序关闭中...")

# Create FastAPI app with lifespan context manager
app = FastAPI(title="CherryAI Backend", version="0.1.0", lifespan=lifespan)

# --- CORS Middleware ---
origins = [ "http://localhost:3000", "http://127.0.0.1:3000" ]
app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# --- API Routers ---
app.include_router(api_router_v1, prefix="/api/v1")

# --- Root Endpoint ---
@app.get("/", tags=["Root"])
async def read_root():
  return {"message": "欢迎来到 CherryAI 后端！"}