package test

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"
)

// Methods to generate private keys. If generation starts slowing down test
// execution then switch over to pre-generated keys.

// NewEC256Key returns an ECDSA key over the P256 curve
func NewEC256Key(tb testing.TB) *ecdsa.PrivateKey {
	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	require.NoError(tb, err)
	return key
}

// NewKeyID returns a random id useful for identifying keys
func NewKeyID(tb testing.TB) string {
	choices := make([]byte, 32)
	_, err := rand.Read(choices)
	require.NoError(tb, err)
	return keyIDFromBytes(choices)
}

func keyIDFromBytes(choices []byte) string {
	const alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	var builder strings.Builder
	for _, choice := range choices {
		builder.WriteByte(alphabet[int(choice)%len(alphabet)])
	}
	return builder.String()
}