"""接口鉴权：从 Authorization 头取出用户中心 token，换取当前用户"""

from fastapi import Depends, Request

from app.clients.user_center import BEARER_CHALLENGE, UserCenterClient, get_user_center
from app.config import settings
from app.core.exceptions import BizException
from app.schemas.user import CurrentUser

# AUTH_ENABLED=false 时所有请求共用的本地调试用户
DEV_USER = CurrentUser(id=0, username="dev")


def _bearer_token(request: Request) -> str:
    scheme, _, token = request.headers.get("Authorization", "").partition(" ")
    token = token.strip()
    if scheme.lower() != "bearer" or not token:
        raise BizException(401, "请先登录", BEARER_CHALLENGE)
    return token


async def get_current_user(
    request: Request, client: UserCenterClient = Depends(get_user_center)
) -> CurrentUser:
    """同一请求内 FastAPI 会缓存结果，路由级和函数级重复声明只校验一次"""
    if not settings.auth_enabled:
        return DEV_USER
    return await client.fetch_current_user(_bearer_token(request))