from datetime import datetime, timedelta, timezone
from typing import Optional
from jose import JWTError, jwt
from app.core.config import settings
from fastapi import Response
from passlib.context import CryptContext

# 密码加密上下文
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    if expires_delta is not None:
        expire = datetime.now(timezone.utc) + expires_delta
        to_encode.update({"exp": expire})
    
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm="HS256")
    return encoded_jwt

def set_jwt_cookie(response: Response, token: str):
    """设置JWT cookie"""
    response.set_cookie(
        key="access_token",
        value=f"Bearer {token}",
        httponly=True,  # 防止JavaScript访问
        secure=not settings.DEBUG,  # 生产环境使用HTTPS
        samesite="lax",  # CSRF保护
        max_age=None if settings.ACCESS_TOKEN_EXPIRE_MINUTES is None 
               else settings.ACCESS_TOKEN_EXPIRE_MINUTES * 60
    )

def clear_jwt_cookie(response: Response):
    """清除JWT cookie"""
    response.delete_cookie(
        key="access_token",
        httponly=True,
        secure=not settings.DEBUG,
        samesite="lax"
    )

def verify_token(token: str) -> Optional[str]:
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=["HS256"])
        phone: str = payload.get("sub")
        if phone is None:
            return None
        return phone
    except JWTError:
        return None 

def get_password_hash(password: str) -> str:
    """获取密码哈希值"""
    return pwd_context.hash(password)

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