from datetime import datetime, timedelta
from typing import Optional, Union, Any

from jose import jwt
from passlib.context import CryptContext
from app.core.config import settings

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")


def create_access_token(
    subject: Union[str, Any], expires_delta: Optional[timedelta] = None
) -> str:
    """
    创建 JWT Access Token

    Args:
        subject: 用户标识（通常是用户名或用户ID）
        expires_delta: 过期时间增量

    Returns:
        JWT token 字符串
    """
    if expires_delta:
        expire = datetime.now() + expires_delta
    else:
        expire = datetime.now() + timedelta(
            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
        )

    to_encode = {
        "exp": expire,
        "sub": str(subject),
        "type": "access",
        "iat": datetime.now(),
    }
    encoded_jwt = jwt.encode(
        to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM
    )
    return encoded_jwt


def create_refresh_token(subject: Union[str, Any]) -> str:
    """
    创建 JWT Refresh Token（长期有效）

    Args:
        subject: 用户标识

    Returns:
        JWT refresh token 字符串
    """
    expire = datetime.now() + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)

    to_encode = {
        "exp": expire,
        "sub": str(subject),
        "type": "refresh",
        "iat": datetime.now(),
    }
    encoded_jwt = jwt.encode(
        to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM
    )
    return encoded_jwt


def verify_password(plain_password: str, hashed_password: str) -> bool:
    """
    验证密码

    Args:
        plain_password: 明文密码
        hashed_password: 密码哈希

    Returns:
        是否匹配
    """
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str) -> str:
    """
    生成密码哈希

    Args:
        password: 明文密码

    Returns:
        bcrypt 哈希字符串
    """
    return pwd_context.hash(password)