from jose import JWTError, jwt
from datetime import datetime, timedelta
from fastapi.security import OAuth2PasswordBearer
from fastapi import Depends, HTTPException

SECRET_KEY = "your-secret-key-change-in-production"   # 生产环境用环境变量
ALGORITHM = "HS256"
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/auth/token")

def create_access_token(data: dict, expires_delta: timedelta):
    to_encode = data.copy()
    expire = datetime.utcnow() + expires_delta
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

def get_current_user(token: str = Depends(oauth2_scheme)):
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        role: str = payload.get("role")
        if username is None:
            raise HTTPException(401, "无效令牌")
        return {"username": username, "role": role}
    except JWTError:
        raise HTTPException(401, "令牌验证失败")