"""FastAPI 应用入口：lifespan 管理 scheduler、首次启动创建 admin。"""
import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from sqlalchemy.exc import OperationalError

from app.api.router import api_router
from app.config import get_settings
from app.database import Base, SessionLocal, engine
from app.models.user import User
from app.scheduler.scheduler import scheduler_lifespan
from app.security import hash_password
from app.utils.logging import setup_logging

setup_logging()
log = logging.getLogger(__name__)
settings = get_settings()


def init_database() -> None:
    """建表（Alembic 是首选；这里兜底确保首次启动也能跑）。"""
    try:
        # 实际生产用 alembic upgrade head；这里仅当表不存在时创建
        Base.metadata.create_all(bind=engine)
        log.info("Database tables ensured")
    except OperationalError as e:
        log.error("Database init failed: %s", e)
        raise


def init_admin() -> None:
    """首次启动创建 admin 账号（仅当 users 表为空时）。"""
    with SessionLocal() as db:
        try:
            existing = db.query(User).count()
            if existing > 0:
                log.info("Existing users found (%d), skip admin init", existing)
                return
            admin = User(
                username="admin",
                password_hash=hash_password(settings.INITIAL_ADMIN_PASSWORD),
                is_admin=True,
                is_active=True,
            )
            db.add(admin)
            db.commit()
            log.warning(
                "Initial admin account created. username=admin  "
                "Please change the password after first login."
            )
        except Exception:
            db.rollback()
            raise


@asynccontextmanager
async def lifespan(app: FastAPI):
    init_database()
    init_admin()
    async with scheduler_lifespan():
        log.info("Application ready")
        yield
    log.info("Application shutting down")


app = FastAPI(
    title="Backup System",
    description="数据备份管理系统 - MySQL / 目录 备份到本地 / S3",
    version="0.1.0",
    lifespan=lifespan,
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.cors_origins_list,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.get("/api/health")
def health() -> dict:
    return {"status": "ok"}


app.include_router(api_router, prefix="/api")


@app.exception_handler(Exception)
async def global_exception_handler(request, exc):
    log.exception("Unhandled error on %s %s", request.method, request.url)
    return JSONResponse(
        status_code=500,
        content={"detail": f"Internal server error: {type(exc).__name__}"},
    )