"""安全模块：密码哈希 + JWT"""

import os
import secrets
import warnings
from datetime import datetime, timedelta, timezone
from typing import Optional
import bcrypt
from jose import jwt, JWTError

# JWT 密钥：生产环境必须通过环境变量 JWT_SECRET_KEY 设置
SECRET_KEY = os.getenv("JWT_SECRET_KEY")
if not SECRET_KEY:
    warnings.warn(
        "未设置 JWT_SECRET_KEY 环境变量，使用临时随机密钥（重启后所有 Token 将失效）。"
        "生产环境请务必设置 JWT_SECRET_KEY 环境变量。",
        stacklevel=2,
    )
    SECRET_KEY = secrets.token_urlsafe(32)
assert SECRET_KEY is not None
SECRET_KEY_TYPED: str = SECRET_KEY
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_HOURS = int(os.getenv("ACCESS_TOKEN_EXPIRE_HOURS", "24"))


def hash_password(password: str) -> str:
    pwd_bytes = password.encode("utf-8")
    # bcrypt 限制72字节，截断
    pwd_bytes = pwd_bytes[:72]
    return bcrypt.hashpw(pwd_bytes, bcrypt.gensalt()).decode("utf-8")


def verify_password(plain: str, hashed: str) -> bool:
    try:
        return bcrypt.checkpw(plain.encode("utf-8")[:72], hashed.encode("utf-8"))
    except Exception:
        return False


def create_access_token(
    data: dict, expires_hours: int = ACCESS_TOKEN_EXPIRE_HOURS
) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + timedelta(hours=expires_hours)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY_TYPED, algorithm=ALGORITHM)


def decode_access_token(token: str) -> Optional[dict]:
    try:
        return jwt.decode(token, SECRET_KEY_TYPED, algorithms=[ALGORITHM])
    except JWTError:
        return None