package otp_test

import (
	"fmt"

	"dev.justinjudd.org/justin/otp"
)

// Just an example for storing OTP keys on the client
var keys map[Key]string

// Key is used as keys for the otp key storing map
type Key struct {
	Issuer, Label string
}

func GetCode(issuer, username string) (string, error) {

	mapKey := Key{issuer, username}

	// Get the stored Key URL
	keyURL, ok := keys[mapKey]
	if !ok {
		return "", nil
	}

	// Build the key from the URL
	key, err := otp.FromURL(keyURL)
	if err != nil {
		return "", err
	}

	// Verify Issuer and Label are correct
	if key.Issuer() != issuer || key.Label() != username {
		return "", nil
	}

	code := key.OTP()

	// If using HOTP, than need to save the state
	keyURL = key.URL()
	keys[mapKey] = keyURL

	return code, nil
}

func Example_hOTPClient() {
	issuer := "example.com"
	username := "username"

	code, err := GetCode(issuer, username)
	if err != nil {
		// Handle error
	}

	// Present code to user, or send code to server
	fmt.Println(code)
}