from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from fastapi import HTTPException, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
import db

SECRET_KEY = "your-secret-key-change-in-production"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 60 * 24

security = HTTPBearer()
optional_security = HTTPBearer(auto_error=False)

import bcrypt

# 使用原生 bcrypt 进行密码校验，解决 passlib 与 bcrypt 5.x 的兼容性问题
def verify_password(plain_password: str, hashed_password: str) -> bool:
    try:
        return bcrypt.checkpw(plain_password.encode('utf-8'), hashed_password.encode('utf-8'))
    except Exception:
        return False

# 使用原生 bcrypt 生成密码哈希
def get_password_hash(password: str) -> str:
    salt = bcrypt.gensalt()
    return bcrypt.hashpw(password.encode('utf-8'), salt).decode('utf-8')

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

def get_current_user(credentials: HTTPAuthorizationCredentials = Depends(security)):
    token = credentials.credentials
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id: int = payload.get("id")
        if user_id is None:
            raise HTTPException(status_code=401, detail="无效的认证信息")
    except JWTError:
        raise HTTPException(status_code=403, detail="登录已过期，请重新登录")
    
    user = db.get_user_by_id(user_id)
    if user is None:
        raise HTTPException(status_code=404, detail="用户不存在")
    return user

def get_optional_user(credentials: Optional[HTTPAuthorizationCredentials] = Depends(optional_security)):
    if not credentials:
        return None
    try:
        payload = jwt.decode(credentials.credentials, SECRET_KEY, algorithms=[ALGORITHM])
        user_id = payload.get("id")
        if user_id:
            return db.get_user_by_id(user_id)
    except JWTError:
        return None
    return None