/*
Copyright 2015 The Kubernetes 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 e2e

import (
	"bytes"
	"crypto/rand"
	"crypto/rsa"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"
	"fmt"
	"io"
	"math/big"
	"net"
	"net/http"
	"strings"
	"time"

	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/apis/extensions"
	client "k8s.io/kubernetes/pkg/client/unversioned"
	utilnet "k8s.io/kubernetes/pkg/util/net"
	"k8s.io/kubernetes/test/e2e/framework"
)

const (
	rsaBits  = 2048
	validFor = 365 * 24 * time.Hour
)

// generateRSACerts generates a basic self signed certificate using a key length
// of rsaBits, valid for validFor time.
func generateRSACerts(host string, isCA bool, keyOut, certOut io.Writer) error {
	if len(host) == 0 {
		return fmt.Errorf("Require a non-empty host for client hello")
	}
	priv, err := rsa.GenerateKey(rand.Reader, rsaBits)
	if err != nil {
		return fmt.Errorf("Failed to generate key: %v", err)
	}
	notBefore := time.Now()
	notAfter := notBefore.Add(validFor)

	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)

	if err != nil {
		return fmt.Errorf("failed to generate serial number: %s", err)
	}
	template := x509.Certificate{
		SerialNumber: serialNumber,
		Subject: pkix.Name{
			CommonName:   "default",
			Organization: []string{"Acme Co"},
		},
		NotBefore: notBefore,
		NotAfter:  notAfter,

		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
	}

	hosts := strings.Split(host, ",")
	for _, h := range hosts {
		if ip := net.ParseIP(h); ip != nil {
			template.IPAddresses = append(template.IPAddresses, ip)
		} else {
			template.DNSNames = append(template.DNSNames, h)
		}
	}

	if isCA {
		template.IsCA = true
		template.KeyUsage |= x509.KeyUsageCertSign
	}

	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
	if err != nil {
		return fmt.Errorf("Failed to create certificate: %s", err)
	}
	if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
		return fmt.Errorf("Failed creating cert: %v", err)
	}
	if err := pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)}); err != nil {
		return fmt.Errorf("Failed creating keay: %v", err)
	}
	return nil
}

// buildTransport creates a transport for use in executing HTTPS requests with
// the given certs. Note that the given rootCA must be configured with isCA=true.
func buildTransport(serverName string, rootCA []byte) (*http.Transport, error) {
	pool := x509.NewCertPool()
	ok := pool.AppendCertsFromPEM(rootCA)
	if !ok {
		return nil, fmt.Errorf("Unable to load serverCA.")
	}
	return utilnet.SetTransportDefaults(&http.Transport{
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: false,
			ServerName:         serverName,
			RootCAs:            pool,
		},
	}), nil
}

// buildInsecureClient returns an insecure http client. Can be used for "curl -k".
func buildInsecureClient(timeout time.Duration) *http.Client {
	t := &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}
	return &http.Client{Timeout: timeout, Transport: utilnet.SetTransportDefaults(t)}
}

// createSecret creates a secret containing TLS certificates for the given Ingress.
// If a secret with the same name already exists in the namespace of the
// Ingress, it's updated.
func createSecret(kubeClient *client.Client, ing *extensions.Ingress) (host string, rootCA, privKey []byte, err error) {
	var k, c bytes.Buffer
	tls := ing.Spec.TLS[0]
	host = strings.Join(tls.Hosts, ",")
	framework.Logf("Generating RSA cert for host %v", host)

	if err = generateRSACerts(host, true, &k, &c); err != nil {
		return
	}
	cert := c.Bytes()
	key := k.Bytes()
	secret := &api.Secret{
		ObjectMeta: api.ObjectMeta{
			Name: tls.SecretName,
		},
		Data: map[string][]byte{
			api.TLSCertKey:       cert,
			api.TLSPrivateKeyKey: key,
		},
	}
	var s *api.Secret
	if s, err = kubeClient.Secrets(ing.Namespace).Get(tls.SecretName); err == nil {
		// TODO: Retry the update. We don't really expect anything to conflict though.
		framework.Logf("Updating secret %v in ns %v with hosts %v for ingress %v", secret.Name, secret.Namespace, host, ing.Name)
		s.Data = secret.Data
		_, err = kubeClient.Secrets(ing.Namespace).Update(s)
	} else {
		framework.Logf("Creating secret %v in ns %v with hosts %v for ingress %v", secret.Name, secret.Namespace, host, ing.Name)
		_, err = kubeClient.Secrets(ing.Namespace).Create(secret)
	}
	return host, cert, key, err
}