// Copyright 2021 Gravitational, Inc
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package sshutils

import (
	"github.com/gravitational/trace"
	"golang.org/x/crypto/ssh"
)

// Fingerprint returns SSH RFC4716 fingerprint of the key
func Fingerprint(key ssh.PublicKey) string {
	return ssh.FingerprintSHA256(key)
}

// AuthorizedKeyFingerprint returns fingerprint from public key
// in authorized key format
func AuthorizedKeyFingerprint(publicKey []byte) (string, error) {
	key, _, _, _, err := ssh.ParseAuthorizedKey(publicKey)
	if err != nil {
		return "", trace.Wrap(err)
	}
	return Fingerprint(key), nil
}

// PrivateKeyFingerprint returns fingerprint of the public key
// extracted from the PEM encoded private key
func PrivateKeyFingerprint(keyBytes []byte) (string, error) {
	signer, err := ssh.ParsePrivateKey(keyBytes)
	if err != nil {
		return "", trace.Wrap(err)
	}
	return Fingerprint(signer.PublicKey()), nil
}