"""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 models import User, UserRole
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)) -> User:
    """从 JWT token 解析当前用户"""
    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])
        user_id: int = payload.get("sub")
        if user_id is None:
            raise credentials_exception
    except JWTError:
        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_role(*roles: UserRole):
    """权限装饰器：要求当前用户具有指定角色之一"""
    def role_checker(current_user: User = Depends(get_current_user)):
        if current_user.role not in [r.value for r in roles] and current_user.role not in roles:
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail="权限不足"
            )
        return current_user
    return role_checker