package main

import (
	"encoding/base64"
	"fmt"
	"log"
	"os"
	"time"

	"github.com/tezli/jwt"
)

func main() {
	key := os.Getenv("JWT_PRIVATE_KEY")
	privateKey, err := base64.StdEncoding.DecodeString(key)
	if err != nil {
		log.Fatalf("Could not read private key: %s", err.Error())
	}

	// selecting an algoithm
	algorithm, err := jwt.NewES256(privateKey)
	if err != nil {
		log.Fatalf("Could not instantiate algorithm: %s", err.Error())
	}

	// creating a token
	then := time.Now().Add(time.Hour).Unix()
	claims := &jwt.Claims{
		Expires: then,
	}
	createdToken, err := jwt.Create(claims, algorithm)
	if err != nil {
		log.Fatalf("Could not create token: %s", err.Error())
	}

	// parsing a token
	parsedToken, err := jwt.Parse(createdToken, algorithm)
	if err != nil {
		log.Fatalf("Could not parse token: %s", err.Error())
	}

	// verifying a token
	if !parsedToken.IsValid() || parsedToken.IsExpired() {
		log.Fatal("Token ist not valid (anymore)")
	}
	fmt.Println("OK")
}