"""JWT 认证 + 权限控制"""
from datetime import datetime, timedelta
from typing import Optional
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from passlib.context import CryptContext
from sqlalchemy.orm import Session
from database import get_db
from config import SECRET_KEY, ALGORITHM, ACCESS_TOKEN_EXPIRE_MINUTES

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/auth/login")


def hash_password(password: str) -> str:
    return pwd_context.hash(password)


def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    """从 JWT token 解析当前用户"""
    from models import User
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="登录已过期，请重新登录",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        sub = payload.get("sub")
        if sub is None:
            raise credentials_exception
        user_id = int(sub)
    except (JWTError, ValueError, TypeError):
        raise credentials_exception

    user = db.query(User).filter(User.id == user_id).first()
    if user is None or not user.is_active:
        raise credentials_exception
    return user


def require_permission(*perms: str):
    """权限校验依赖：要求当前用户拥有指定权限中的至少一项"""
    def perm_checker(current_user=Depends(get_current_user)):
        if not current_user.role_ref:
            raise HTTPException(status_code=403, detail="未分配角色")
        user_perms = current_user.permissions or []
        if not any(p in user_perms for p in perms):
            raise HTTPException(status_code=403, detail="权限不足")
        return current_user
    return perm_checker