/*
Copyright 2019 The Jetstack cert-manager contributors.

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 selfsigned

import (
	"context"

	corev1 "k8s.io/api/core/v1"
	k8sErrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/klog"

	"github.com/jetstack/cert-manager/pkg/apis/certmanager/v1alpha1"
	"github.com/jetstack/cert-manager/pkg/issuer"
	"github.com/jetstack/cert-manager/pkg/util/errors"
	"github.com/jetstack/cert-manager/pkg/util/kube"
	"github.com/jetstack/cert-manager/pkg/util/pki"
)

func (c *SelfSigned) Issue(ctx context.Context, crt *v1alpha1.Certificate) (*issuer.IssueResponse, error) {
	// get a copy of the existing/currently issued Certificate's private key
	signeePrivateKey, err := kube.SecretTLSKey(ctx, c.secretsLister, crt.Namespace, crt.Spec.SecretName)
	if k8sErrors.IsNotFound(err) || errors.IsInvalidData(err) {
		// if one does not already exist, generate a new one
		signeePrivateKey, err = pki.GeneratePrivateKeyForCertificate(crt)
		if err != nil {
			c.Recorder.Eventf(crt, corev1.EventTypeWarning, "PrivateKeyError", "Error generating certificate private key: %v", err)
			// don't trigger a retry. An error from this function implies some
			// invalid input parameters, and retrying without updating the
			// resource will not help.
			return nil, nil
		}
	}
	if err != nil {
		klog.Errorf("Error getting private key %q for certificate: %v", crt.Spec.SecretName, err)
		return nil, err
	}

	// extract the public component of the key
	signeePublicKey, err := pki.PublicKeyForPrivateKey(signeePrivateKey)
	if err != nil {
		klog.Errorf("Error getting public key from private key: %v", err)
		return nil, err
	}

	// generate a x509 certificate template for this Certificate
	template, err := pki.GenerateTemplate(crt)
	if err != nil {
		c.Recorder.Eventf(crt, corev1.EventTypeWarning, "ErrorSigning", "Error signing certificate: %v", err)
		return nil, err
	}

	// sign and encode the certificate
	certPem, _, err := pki.SignCertificate(template, template, signeePublicKey, signeePrivateKey)
	if err != nil {
		c.Recorder.Eventf(crt, corev1.EventTypeWarning, "ErrorSigning", "Error signing certificate: %v", err)
		return nil, err
	}

	// Encode output private key
	keyPem, err := pki.EncodePrivateKey(signeePrivateKey, crt.Spec.KeyEncoding)
	if err != nil {
		c.Recorder.Eventf(crt, corev1.EventTypeWarning, "ErrorPrivateKey", "Error encoding private key: %v", err)
		return nil, err
	}

	return &issuer.IssueResponse{
		PrivateKey:  keyPem,
		Certificate: certPem,
		CA:          certPem,
	}, nil
}
