package auth

import (
	"github.com/dgrijalva/jwt-go"
	"github.com/pkg/errors"
	"time"
)

func newJWT(jwtSecretKey string, userID string, expSec int64) (string, error) {
	token := jwt.New(jwt.SigningMethodHS256)
	claims := make(jwt.MapClaims)

	if expSec > 0 {
		claims["exp"] = time.Now().Add(time.Duration(expSec) * time.Second).Unix()
	}

	claims["aud"] = userID
	claims["iat"] = time.Now().Unix()
	token.Claims = claims

	tokenString, err := token.SignedString([]byte(jwtSecretKey))
	if err != nil {
		return "", errors.New(err.Error())
	}

	return tokenString, nil
}

func checkJWT(jwtSecretKey string, tokenStr string) (bool, string, error) {
	token, err := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
		return []byte(jwtSecretKey), nil
	})
	if err != nil {
		var validationErr *jwt.ValidationError

		ok := errors.As(err, &validationErr)
		if !ok {
			return false, "", errors.New(err.Error())
		}

		if validationErr.Errors == jwt.ValidationErrorExpired {
			return false, "", nil
		}

		return false, "", errors.New(err.Error())
	}

	claims, ok := token.Claims.(jwt.MapClaims)
	if !ok {
		return false, "", errors.New("类型转换失败")
	}

	userID, ok := claims["aud"].(string)
	if !ok {
		return false, "", errors.New("类型转换失败")
	}

	return token.Valid, userID, nil
}