package jwt

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
)

func NewHMACKey(n int) []byte {
	res := make([]byte, n)
	rand.Reader.Read(res)
	return res
}

func CachedRSAkey() (*rsa.PrivateKey, error) {
	keyPath := filepath.Join(os.TempDir(), "narco-jwt-test.key")
	f, err := os.Open(keyPath)
	if err != nil {
		if os.IsNotExist(err) == false {
			return nil, err
		}
		// generate a key
		log.Printf("Generating a new key")
		key, err := rsa.GenerateKey(rand.Reader, 1024)
		if err != nil {
			return nil, err
		}

		f, err := os.Create(keyPath)
		if err != nil {
			log.Printf("Could not cache the generated key: %s", err)
			return key, nil
		}

		data := x509.MarshalPKCS1PrivateKey(key)
		_, err = f.Write(data)
		if err != nil {
			log.Printf("Could not cache the generated key: %s", err)
		}

		return key, nil
	}

	keydata, err := ioutil.ReadAll(f)
	if err != nil {
		return nil, fmt.Errorf("Could not read %s: %s", keyPath, err)
	}

	return x509.ParsePKCS1PrivateKey(keydata)
}