// Copyright 2020 Lingfei Kong <colin404@foxmail.com>. All rights reserved.
// Use of this source code is governed by a MIT style
// license that can be found in the LICENSE file.

package main

import (
	"fmt"

	"github.com/golang-jwt/jwt/v4"
)

func main() {
	rawJWT := `eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJpYW0uYXV0aHoubWFybW90ZWR1LmNvbSIsImV4cCI6MTYwNDEyODQwMywiaWF0IjoxNjA0MTI4NDAyLCJpc3MiOiJpYW1jdGwiLCJraWQiOiJpZDEifQ.Itr5u4C-nTeA01qbjjl7RzuPD-aSQazsJZY_Z25aGnI`

	// Verify the token
	claims := &jwt.MapClaims{}
	parsedT, err := jwt.ParseWithClaims(rawJWT, claims, func(token *jwt.Token) (interface{}, error) {
		// Validate the alg is HMAC signature
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}

		if kid, ok := token.Header["kid"].(string); ok {
			fmt.Println("kid", kid)
		}

		return []byte("key1"), nil
	})

	if err != nil || !parsedT.Valid {
		fmt.Println("token valid failed", err)

		return
	}

	fmt.Println("ok")
}