/*
 *
 * Copyright 2020 The KubeSphere Authors.
 *
 * 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 pkiutil

import (
	"crypto"
	cryptorand "crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"github.com/pkg/errors"
	certutil "k8s.io/client-go/util/cert"
)

// NewCSRAndKey generates a new key and CSR and that could be signed to create the given certificate
func NewCSRAndKey(config *certutil.Config) (*x509.CertificateRequest, *rsa.PrivateKey, error) {
	key, err := certutil.NewPrivateKey()
	if err != nil {
		return nil, nil, errors.Wrap(err, "unable to create private key")
	}

	csr, err := NewCSR(*config, key)
	if err != nil {
		return nil, nil, errors.Wrap(err, "unable to generate CSR")
	}

	return csr, key, nil
}

// NewCSR creates a new CSR
func NewCSR(cfg certutil.Config, key crypto.Signer) (*x509.CertificateRequest, error) {
	template := &x509.CertificateRequest{
		Subject: pkix.Name{
			CommonName:   cfg.CommonName,
			Organization: cfg.Organization,
		},
		DNSNames:    cfg.AltNames.DNSNames,
		IPAddresses: cfg.AltNames.IPs,
	}

	csrBytes, err := x509.CreateCertificateRequest(cryptorand.Reader, template, key)

	if err != nil {
		return nil, errors.Wrap(err, "failed to create a CSR")
	}

	return x509.ParseCertificateRequest(csrBytes)
}