"""
路由公共依赖。

提供“可选登录”依赖与权限判断工具：
- 文章可见性控制需要区分“游客”和“登录用户”
- 携带有效令牌时返回用户，未携带令牌时返回 None
"""

from typing import Optional

from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPAuthorizationCredentials
from sqlalchemy.orm import Session

from ..auth import bearer_scheme, decode_token
from ..database import get_db
from ..models import ROLE_BLOGGER, ROLE_FRIEND, User


def get_optional_user(
    credentials: HTTPAuthorizationCredentials = Depends(bearer_scheme),
    db: Session = Depends(get_db),
) -> Optional[User]:
    """可选登录依赖：未携带令牌返回 None；令牌无效返回 401；否则返回当前用户。"""
    if credentials is None:
        return None
    payload = decode_token(credentials.credentials)
    try:
        user_id = int(payload.get("sub"))
    except (TypeError, ValueError):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="令牌无效")
    user = db.query(User).filter(User.id == user_id).first()
    # 令牌版本校验：与 get_current_user 保持一致，密码重置后旧令牌失效
    if user is not None and (payload.get("ver") or 0) != (user.token_version or 0):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="登录状态已失效，请重新登录")
    return user


def can_read_friend_article(user: Optional[User]) -> bool:
    """判断用户是否具备查看好友文章的权限（friend / blogger）。"""
    return user is not None and user.role in (ROLE_FRIEND, ROLE_BLOGGER)