package control

import (
	"context"
	"crypto"
	cryptorand "crypto/rand"
	"crypto/x509"
	b64 "encoding/base64"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"math/rand"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"text/template"
	"time"

	"k8s.io/apimachinery/pkg/util/sets"

	"github.com/pkg/errors"
	certutil "github.com/rancher/dynamiclistener/cert"
	"github.com/rancher/k3s/pkg/clientaccess"
	"github.com/rancher/k3s/pkg/cluster"
	"github.com/rancher/k3s/pkg/daemons/config"
	"github.com/rancher/k3s/pkg/daemons/executor"
	"github.com/rancher/k3s/pkg/passwd"
	"github.com/rancher/k3s/pkg/token"
	"github.com/rancher/k3s/pkg/version"
	"github.com/rancher/wrangler-api/pkg/generated/controllers/rbac"
	"github.com/sirupsen/logrus"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	apiserverconfigv1 "k8s.io/apiserver/pkg/apis/config/v1"
	"k8s.io/apiserver/pkg/authentication/authenticator"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	ccm "k8s.io/cloud-provider"
	ccmapp "k8s.io/cloud-provider/app"
	ccmopt "k8s.io/cloud-provider/options"
	app2 "k8s.io/controller-manager/app"
	"k8s.io/kubernetes/pkg/controlplane"
	"k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes"
	"k8s.io/kubernetes/pkg/proxy/util"

	// registering k3s cloud provider
	_ "github.com/rancher/k3s/pkg/cloudprovider"
	// for client metric registration
	_ "k8s.io/component-base/metrics/prometheus/restclient"
)

var (
	localhostIP        = net.ParseIP("127.0.0.1")
	requestHeaderCN    = "system:auth-proxy"
	kubeconfigTemplate = template.Must(template.New("kubeconfig").Parse(`apiVersion: v1
clusters:
- cluster:
    server: {{.URL}}
    certificate-authority: {{.CACert}}
  name: local
contexts:
- context:
    cluster: local
    namespace: default
    user: user
  name: Default
current-context: Default
kind: Config
preferences: {}
users:
- name: user
  user:
    client-certificate: {{.ClientCert}}
    client-key: {{.ClientKey}}
`))
)

const (
	ipsecTokenSize = 48
	aescbcKeySize  = 32
)

func Server(ctx context.Context, cfg *config.Control) error {
	rand.Seed(time.Now().UTC().UnixNano())

	runtime := &config.ControlRuntime{}
	cfg.Runtime = runtime

	if err := prepare(ctx, cfg, runtime); err != nil {
		return errors.Wrap(err, "preparing server")
	}

	cfg.Runtime.Tunnel = setupTunnel()
	util.DisableProxyHostnameCheck = true

	auth, handler, err := apiServer(ctx, cfg, runtime)
	if err != nil {
		return err
	}

	if err := waitForAPIServerInBackground(ctx, runtime); err != nil {
		return err
	}

	basicAuth, err := basicAuthenticator(runtime.PasswdFile)
	if err != nil {
		return err
	}

	runtime.Authenticator = combineAuthenticators(basicAuth, auth)
	runtime.Handler = handler

	if !cfg.NoScheduler {
		if err := scheduler(cfg, runtime); err != nil {
			return err
		}
	}

	if err := controllerManager(cfg, runtime); err != nil {
		return err
	}

	if !cfg.DisableCCM {
		cloudControllerManager(ctx, cfg, runtime)
	}

	return nil
}

func controllerManager(cfg *config.Control, runtime *config.ControlRuntime) error {
	argsMap := map[string]string{
		"kubeconfig":                       runtime.KubeConfigController,
		"service-account-private-key-file": runtime.ServiceKey,
		"allocate-node-cidrs":              "true",
		"cluster-cidr":                     cfg.ClusterIPRange.String(),
		"root-ca-file":                     runtime.ServerCA,
		"port":                             "10252",
		"profiling":                        "false",
		"address":                          localhostIP.String(),
		"bind-address":                     localhostIP.String(),
		"secure-port":                      "0",
		"use-service-account-credentials":  "true",
		"cluster-signing-cert-file":        runtime.ClientCA,
		"cluster-signing-key-file":         runtime.ClientCAKey,
	}
	if cfg.NoLeaderElect {
		argsMap["leader-elect"] = "false"
	}
	if !cfg.DisableCCM {
		argsMap["configure-cloud-routes"] = "false"
		argsMap["controllers"] = "*,-service,-route,-cloud-node-lifecycle"
	}

	args := config.GetArgsList(argsMap, cfg.ExtraControllerArgs)
	logrus.Infof("Running kube-controller-manager %s", config.ArgString(args))

	return executor.ControllerManager(runtime.APIServerReady, args)
}

func scheduler(cfg *config.Control, runtime *config.ControlRuntime) error {
	argsMap := map[string]string{
		"kubeconfig":   runtime.KubeConfigScheduler,
		"port":         "10251",
		"address":      "127.0.0.1",
		"bind-address": "127.0.0.1",
		"secure-port":  "0",
		"profiling":    "false",
	}
	if cfg.NoLeaderElect {
		argsMap["leader-elect"] = "false"
	}
	args := config.GetArgsList(argsMap, cfg.ExtraSchedulerAPIArgs)

	logrus.Infof("Running kube-scheduler %s", config.ArgString(args))
	return executor.Scheduler(runtime.APIServerReady, args)
}

func apiServer(ctx context.Context, cfg *config.Control, runtime *config.ControlRuntime) (authenticator.Request, http.Handler, error) {
	argsMap := make(map[string]string)

	setupStorageBackend(argsMap, cfg)

	certDir := filepath.Join(cfg.DataDir, "tls", "temporary-certs")
	os.MkdirAll(certDir, 0700)

	argsMap["cert-dir"] = certDir
	argsMap["allow-privileged"] = "true"
	argsMap["authorization-mode"] = strings.Join([]string{modes.ModeNode, modes.ModeRBAC}, ",")
	argsMap["service-account-signing-key-file"] = runtime.ServiceKey
	argsMap["service-cluster-ip-range"] = cfg.ServiceIPRange.String()
	argsMap["advertise-port"] = strconv.Itoa(cfg.AdvertisePort)
	if cfg.AdvertiseIP != "" {
		argsMap["advertise-address"] = cfg.AdvertiseIP
	}
	argsMap["insecure-port"] = "0"
	argsMap["secure-port"] = strconv.Itoa(cfg.APIServerPort)
	if cfg.APIServerBindAddress == "" {
		argsMap["bind-address"] = localhostIP.String()
	} else {
		argsMap["bind-address"] = cfg.APIServerBindAddress
	}
	argsMap["tls-cert-file"] = runtime.ServingKubeAPICert
	argsMap["tls-private-key-file"] = runtime.ServingKubeAPIKey
	argsMap["service-account-key-file"] = runtime.ServiceKey
	argsMap["service-account-issuer"] = version.Program
	argsMap["api-audiences"] = "unknown"
	argsMap["kubelet-certificate-authority"] = runtime.ServerCA
	argsMap["kubelet-client-certificate"] = runtime.ClientKubeAPICert
	argsMap["kubelet-client-key"] = runtime.ClientKubeAPIKey
	argsMap["requestheader-client-ca-file"] = runtime.RequestHeaderCA
	argsMap["requestheader-allowed-names"] = requestHeaderCN
	argsMap["proxy-client-cert-file"] = runtime.ClientAuthProxyCert
	argsMap["proxy-client-key-file"] = runtime.ClientAuthProxyKey
	argsMap["requestheader-extra-headers-prefix"] = "X-Remote-Extra-"
	argsMap["requestheader-group-headers"] = "X-Remote-Group"
	argsMap["requestheader-username-headers"] = "X-Remote-User"
	argsMap["client-ca-file"] = runtime.ClientCA
	argsMap["enable-admission-plugins"] = "NodeRestriction"
	argsMap["anonymous-auth"] = "false"
	argsMap["profiling"] = "false"
	argsMap["feature-gates=ServiceAccountIssuerDiscovery"] = "false"
	if cfg.EncryptSecrets {
		argsMap["encryption-provider-config"] = runtime.EncryptionConfig
	}
	args := config.GetArgsList(argsMap, cfg.ExtraAPIArgs)

	logrus.Infof("Running kube-apiserver %s", config.ArgString(args))
	return executor.APIServer(ctx, runtime.ETCDReady, args)
}

func defaults(config *config.Control) {
	if config.ClusterIPRange == nil {
		_, clusterIPNet, _ := net.ParseCIDR("10.42.0.0/16")
		config.ClusterIPRange = clusterIPNet
	}

	if config.ServiceIPRange == nil {
		_, serviceIPNet, _ := net.ParseCIDR("10.43.0.0/16")
		config.ServiceIPRange = serviceIPNet
	}

	if len(config.ClusterDNS) == 0 {
		config.ClusterDNS = net.ParseIP("10.43.0.10")
	}

	if config.AdvertisePort == 0 {
		config.AdvertisePort = config.HTTPSPort
	}

	if config.APIServerPort == 0 {
		if config.HTTPSPort != 0 {
			config.APIServerPort = config.HTTPSPort + 1
		} else {
			config.APIServerPort = 6444
		}
	}

	if config.DataDir == "" {
		config.DataDir = "./management-state"
	}
}

func prepare(ctx context.Context, config *config.Control, runtime *config.ControlRuntime) error {
	var err error

	defaults(config)

	if err := os.MkdirAll(config.DataDir, 0700); err != nil {
		return err
	}

	config.DataDir, err = filepath.Abs(config.DataDir)
	if err != nil {
		return err
	}

	os.MkdirAll(filepath.Join(config.DataDir, "tls"), 0700)
	os.MkdirAll(filepath.Join(config.DataDir, "cred"), 0700)

	runtime.ClientCA = filepath.Join(config.DataDir, "tls", "client-ca.crt")
	runtime.ClientCAKey = filepath.Join(config.DataDir, "tls", "client-ca.key")
	runtime.ServerCA = filepath.Join(config.DataDir, "tls", "server-ca.crt")
	runtime.ServerCAKey = filepath.Join(config.DataDir, "tls", "server-ca.key")
	runtime.RequestHeaderCA = filepath.Join(config.DataDir, "tls", "request-header-ca.crt")
	runtime.RequestHeaderCAKey = filepath.Join(config.DataDir, "tls", "request-header-ca.key")
	runtime.IPSECKey = filepath.Join(config.DataDir, "cred", "ipsec.psk")

	runtime.ServiceKey = filepath.Join(config.DataDir, "tls", "service.key")
	runtime.PasswdFile = filepath.Join(config.DataDir, "cred", "passwd")
	runtime.NodePasswdFile = filepath.Join(config.DataDir, "cred", "node-passwd")

	runtime.KubeConfigAdmin = filepath.Join(config.DataDir, "cred", "admin.kubeconfig")
	runtime.KubeConfigController = filepath.Join(config.DataDir, "cred", "controller.kubeconfig")
	runtime.KubeConfigScheduler = filepath.Join(config.DataDir, "cred", "scheduler.kubeconfig")
	runtime.KubeConfigAPIServer = filepath.Join(config.DataDir, "cred", "api-server.kubeconfig")
	runtime.KubeConfigCloudController = filepath.Join(config.DataDir, "cred", "cloud-controller.kubeconfig")

	runtime.ClientAdminCert = filepath.Join(config.DataDir, "tls", "client-admin.crt")
	runtime.ClientAdminKey = filepath.Join(config.DataDir, "tls", "client-admin.key")
	runtime.ClientControllerCert = filepath.Join(config.DataDir, "tls", "client-controller.crt")
	runtime.ClientControllerKey = filepath.Join(config.DataDir, "tls", "client-controller.key")
	runtime.ClientCloudControllerCert = filepath.Join(config.DataDir, "tls", "client-cloud-controller.crt")
	runtime.ClientCloudControllerKey = filepath.Join(config.DataDir, "tls", "client-cloud-controller.key")
	runtime.ClientSchedulerCert = filepath.Join(config.DataDir, "tls", "client-scheduler.crt")
	runtime.ClientSchedulerKey = filepath.Join(config.DataDir, "tls", "client-scheduler.key")
	runtime.ClientKubeAPICert = filepath.Join(config.DataDir, "tls", "client-kube-apiserver.crt")
	runtime.ClientKubeAPIKey = filepath.Join(config.DataDir, "tls", "client-kube-apiserver.key")
	runtime.ClientKubeProxyCert = filepath.Join(config.DataDir, "tls", "client-kube-proxy.crt")
	runtime.ClientKubeProxyKey = filepath.Join(config.DataDir, "tls", "client-kube-proxy.key")
	runtime.ClientK3sControllerCert = filepath.Join(config.DataDir, "tls", "client-"+version.Program+"-controller.crt")
	runtime.ClientK3sControllerKey = filepath.Join(config.DataDir, "tls", "client-"+version.Program+"-controller.key")

	runtime.ServingKubeAPICert = filepath.Join(config.DataDir, "tls", "serving-kube-apiserver.crt")
	runtime.ServingKubeAPIKey = filepath.Join(config.DataDir, "tls", "serving-kube-apiserver.key")

	runtime.ClientKubeletKey = filepath.Join(config.DataDir, "tls", "client-kubelet.key")
	runtime.ServingKubeletKey = filepath.Join(config.DataDir, "tls", "serving-kubelet.key")

	runtime.ClientAuthProxyCert = filepath.Join(config.DataDir, "tls", "client-auth-proxy.crt")
	runtime.ClientAuthProxyKey = filepath.Join(config.DataDir, "tls", "client-auth-proxy.key")

	runtime.ETCDServerCA = filepath.Join(config.DataDir, "tls", "etcd", "server-ca.crt")
	runtime.ETCDServerCAKey = filepath.Join(config.DataDir, "tls", "etcd", "server-ca.key")
	runtime.ETCDPeerCA = filepath.Join(config.DataDir, "tls", "etcd", "peer-ca.crt")
	runtime.ETCDPeerCAKey = filepath.Join(config.DataDir, "tls", "etcd", "peer-ca.key")
	runtime.ServerETCDCert = filepath.Join(config.DataDir, "tls", "etcd", "server-client.crt")
	runtime.ServerETCDKey = filepath.Join(config.DataDir, "tls", "etcd", "server-client.key")
	runtime.PeerServerClientETCDCert = filepath.Join(config.DataDir, "tls", "etcd", "peer-server-client.crt")
	runtime.PeerServerClientETCDKey = filepath.Join(config.DataDir, "tls", "etcd", "peer-server-client.key")
	runtime.ClientETCDCert = filepath.Join(config.DataDir, "tls", "etcd", "client.crt")
	runtime.ClientETCDKey = filepath.Join(config.DataDir, "tls", "etcd", "client.key")

	if config.EncryptSecrets {
		runtime.EncryptionConfig = filepath.Join(config.DataDir, "cred", "encryption-config.json")
	}

	cluster := cluster.New(config)

	if err := cluster.Bootstrap(ctx); err != nil {
		return err
	}

	if err := genCerts(config, runtime); err != nil {
		return err
	}

	if err := genServiceAccount(runtime); err != nil {
		return err
	}

	if err := genUsers(config, runtime); err != nil {
		return err
	}

	if err := genEncryptedNetworkInfo(config, runtime); err != nil {
		return err
	}

	if err := genEncryptionConfig(config, runtime); err != nil {
		return err
	}

	if err := readTokens(runtime); err != nil {
		return err
	}

	ready, err := cluster.Start(ctx)
	if err != nil {
		return err
	}

	runtime.ETCDReady = ready
	return nil
}

func readTokens(runtime *config.ControlRuntime) error {
	tokens, err := passwd.Read(runtime.PasswdFile)
	if err != nil {
		return err
	}

	if nodeToken, ok := tokens.Pass("node"); ok {
		runtime.AgentToken = "node:" + nodeToken
	}
	if serverToken, ok := tokens.Pass("server"); ok {
		runtime.ServerToken = "server:" + serverToken
	}

	return nil
}

func genEncryptedNetworkInfo(controlConfig *config.Control, runtime *config.ControlRuntime) error {
	if s, err := os.Stat(runtime.IPSECKey); err == nil && s.Size() > 0 {
		psk, err := ioutil.ReadFile(runtime.IPSECKey)
		if err != nil {
			return err
		}
		controlConfig.IPSECPSK = strings.TrimSpace(string(psk))
		return nil
	}

	psk, err := token.Random(ipsecTokenSize)
	if err != nil {
		return err
	}

	controlConfig.IPSECPSK = psk
	if err := ioutil.WriteFile(runtime.IPSECKey, []byte(psk+"\n"), 0600); err != nil {
		return err
	}

	return nil
}

func migratePassword(p *passwd.Passwd) error {
	server, _ := p.Pass("server")
	node, _ := p.Pass("node")
	if server == "" && node != "" {
		return p.EnsureUser("server", version.Program+":server", node)
	}
	return nil
}

func getServerPass(passwd *passwd.Passwd, config *config.Control) (string, error) {
	var (
		err error
	)

	serverPass := config.Token
	if serverPass == "" {
		serverPass, _ = passwd.Pass("server")
	}
	if serverPass == "" {
		serverPass, err = token.Random(16)
		if err != nil {
			return "", err
		}
	}

	return serverPass, nil
}

func getNodePass(config *config.Control, serverPass string) string {
	if config.AgentToken == "" {
		if _, passwd, ok := clientaccess.ParseUsernamePassword(serverPass); ok {
			return passwd
		}
		return serverPass
	}
	return config.AgentToken
}

func genUsers(config *config.Control, runtime *config.ControlRuntime) error {
	passwd, err := passwd.Read(runtime.PasswdFile)
	if err != nil {
		return err
	}

	if err := migratePassword(passwd); err != nil {
		return err
	}

	serverPass, err := getServerPass(passwd, config)
	if err != nil {
		return err
	}

	nodePass := getNodePass(config, serverPass)

	if err := passwd.EnsureUser("node", version.Program+":agent", nodePass); err != nil {
		return err
	}

	if err := passwd.EnsureUser("server", version.Program+":server", serverPass); err != nil {
		return err
	}

	return passwd.Write(runtime.PasswdFile)
}

func genCerts(config *config.Control, runtime *config.ControlRuntime) error {
	if err := genClientCerts(config, runtime); err != nil {
		return err
	}
	if err := genServerCerts(config, runtime); err != nil {
		return err
	}
	if err := genRequestHeaderCerts(config, runtime); err != nil {
		return err
	}
	if err := genETCDCerts(config, runtime); err != nil {
		return err
	}
	return nil
}

type signedCertFactory = func(commonName string, organization []string, certFile, keyFile string) (bool, error)

func getSigningCertFactory(regen bool, altNames *certutil.AltNames, extKeyUsage []x509.ExtKeyUsage, caCertFile, caKeyFile string) signedCertFactory {
	return func(commonName string, organization []string, certFile, keyFile string) (bool, error) {
		return createClientCertKey(regen, commonName, organization, altNames, extKeyUsage, caCertFile, caKeyFile, certFile, keyFile)
	}
}

func genClientCerts(config *config.Control, runtime *config.ControlRuntime) error {
	regen, err := createSigningCertKey(version.Program+"-client", runtime.ClientCA, runtime.ClientCAKey)
	if err != nil {
		return err
	}

	factory := getSigningCertFactory(regen, nil, []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth}, runtime.ClientCA, runtime.ClientCAKey)

	var certGen bool
	apiEndpoint := fmt.Sprintf("https://127.0.0.1:%d", config.APIServerPort)

	certGen, err = factory("system:admin", []string{"system:masters"}, runtime.ClientAdminCert, runtime.ClientAdminKey)
	if err != nil {
		return err
	}
	if certGen {
		if err := KubeConfig(runtime.KubeConfigAdmin, apiEndpoint, runtime.ServerCA, runtime.ClientAdminCert, runtime.ClientAdminKey); err != nil {
			return err
		}
	}

	certGen, err = factory("system:kube-controller-manager", nil, runtime.ClientControllerCert, runtime.ClientControllerKey)
	if err != nil {
		return err
	}
	if certGen {
		if err := KubeConfig(runtime.KubeConfigController, apiEndpoint, runtime.ServerCA, runtime.ClientControllerCert, runtime.ClientControllerKey); err != nil {
			return err
		}
	}

	certGen, err = factory("system:kube-scheduler", nil, runtime.ClientSchedulerCert, runtime.ClientSchedulerKey)
	if err != nil {
		return err
	}
	if certGen {
		if err := KubeConfig(runtime.KubeConfigScheduler, apiEndpoint, runtime.ServerCA, runtime.ClientSchedulerCert, runtime.ClientSchedulerKey); err != nil {
			return err
		}
	}

	certGen, err = factory("kube-apiserver", nil, runtime.ClientKubeAPICert, runtime.ClientKubeAPIKey)
	if err != nil {
		return err
	}
	if certGen {
		if err := KubeConfig(runtime.KubeConfigAPIServer, apiEndpoint, runtime.ServerCA, runtime.ClientKubeAPICert, runtime.ClientKubeAPIKey); err != nil {
			return err
		}
	}

	if _, err = factory("system:kube-proxy", nil, runtime.ClientKubeProxyCert, runtime.ClientKubeProxyKey); err != nil {
		return err
	}
	// This user (system:k3s-controller by default) must be bound to a role in rolebindings.yaml or the downstream equivalent
	if _, err = factory("system:"+version.Program+"-controller", nil, runtime.ClientK3sControllerCert, runtime.ClientK3sControllerKey); err != nil {
		return err
	}

	if _, _, err := certutil.LoadOrGenerateKeyFile(runtime.ClientKubeletKey, regen); err != nil {
		return err
	}

	certGen, err = factory("cloud-controller-manager", nil, runtime.ClientCloudControllerCert, runtime.ClientCloudControllerKey)
	if err != nil {
		return err
	}
	if certGen {
		if err := KubeConfig(runtime.KubeConfigCloudController, apiEndpoint, runtime.ServerCA, runtime.ClientCloudControllerCert, runtime.ClientCloudControllerKey); err != nil {
			return err
		}
	}

	return nil
}

func createServerSigningCertKey(config *config.Control, runtime *config.ControlRuntime) (bool, error) {
	TokenCA := filepath.Join(config.DataDir, "tls", "token-ca.crt")
	TokenCAKey := filepath.Join(config.DataDir, "tls", "token-ca.key")

	if exists(TokenCA, TokenCAKey) && !exists(runtime.ServerCA) && !exists(runtime.ServerCAKey) {
		logrus.Infof("Upgrading token-ca files to server-ca")
		if err := os.Link(TokenCA, runtime.ServerCA); err != nil {
			return false, err
		}
		if err := os.Link(TokenCAKey, runtime.ServerCAKey); err != nil {
			return false, err
		}
		return true, nil
	}
	return createSigningCertKey(version.Program+"-server", runtime.ServerCA, runtime.ServerCAKey)
}

func addSANs(altNames *certutil.AltNames, sans []string) {
	for _, san := range sans {
		ip := net.ParseIP(san)
		if ip == nil {
			altNames.DNSNames = append(altNames.DNSNames, san)
		} else {
			altNames.IPs = append(altNames.IPs, ip)
		}
	}
}

func genServerCerts(config *config.Control, runtime *config.ControlRuntime) error {
	regen, err := createServerSigningCertKey(config, runtime)
	if err != nil {
		return err
	}

	_, apiServerServiceIP, err := controlplane.ServiceIPRange(*config.ServiceIPRange)
	if err != nil {
		return err
	}

	altNames := &certutil.AltNames{
		DNSNames: []string{"kubernetes.default.svc", "kubernetes.default", "kubernetes", "localhost"},
		IPs:      []net.IP{apiServerServiceIP},
	}

	addSANs(altNames, config.SANs)

	if _, err := createClientCertKey(regen, "kube-apiserver", nil,
		altNames, []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		runtime.ServerCA, runtime.ServerCAKey,
		runtime.ServingKubeAPICert, runtime.ServingKubeAPIKey); err != nil {
		return err
	}

	if _, _, err := certutil.LoadOrGenerateKeyFile(runtime.ServingKubeletKey, regen); err != nil {
		return err
	}

	return nil
}

func genETCDCerts(config *config.Control, runtime *config.ControlRuntime) error {
	regen, err := createSigningCertKey("etcd-server", runtime.ETCDServerCA, runtime.ETCDServerCAKey)
	if err != nil {
		return err
	}

	altNames := &certutil.AltNames{
		DNSNames: []string{"localhost"},
	}
	addSANs(altNames, config.SANs)

	if _, err := createClientCertKey(regen, "etcd-server", nil,
		altNames, []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
		runtime.ETCDServerCA, runtime.ETCDServerCAKey,
		runtime.ServerETCDCert, runtime.ServerETCDKey); err != nil {
		return err
	}

	if _, err := createClientCertKey(regen, "etcd-client", nil,
		nil, []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
		runtime.ETCDServerCA, runtime.ETCDServerCAKey,
		runtime.ClientETCDCert, runtime.ClientETCDKey); err != nil {
		return err
	}

	regen, err = createSigningCertKey("etcd-peer", runtime.ETCDPeerCA, runtime.ETCDPeerCAKey)
	if err != nil {
		return err
	}

	if _, err := createClientCertKey(regen, "etcd-peer", nil,
		altNames, []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
		runtime.ETCDPeerCA, runtime.ETCDPeerCAKey,
		runtime.PeerServerClientETCDCert, runtime.PeerServerClientETCDKey); err != nil {
		return err
	}

	return nil
}

func genRequestHeaderCerts(config *config.Control, runtime *config.ControlRuntime) error {
	regen, err := createSigningCertKey(version.Program+"-request-header", runtime.RequestHeaderCA, runtime.RequestHeaderCAKey)
	if err != nil {
		return err
	}

	if _, err := createClientCertKey(regen, requestHeaderCN, nil,
		nil, []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
		runtime.RequestHeaderCA, runtime.RequestHeaderCAKey,
		runtime.ClientAuthProxyCert, runtime.ClientAuthProxyKey); err != nil {
		return err
	}

	return nil
}

func createClientCertKey(regen bool, commonName string, organization []string, altNames *certutil.AltNames, extKeyUsage []x509.ExtKeyUsage, caCertFile, caKeyFile, certFile, keyFile string) (bool, error) {
	caBytes, err := ioutil.ReadFile(caCertFile)
	if err != nil {
		return false, err
	}

	pool := x509.NewCertPool()
	pool.AppendCertsFromPEM(caBytes)

	// check for certificate expiration
	if !regen {
		regen = expired(certFile, pool)
	}

	if !regen {
		regen = sansChanged(certFile, altNames)
	}

	if !regen {
		if exists(certFile, keyFile) {
			return false, nil
		}
	}

	caKeyBytes, err := ioutil.ReadFile(caKeyFile)
	if err != nil {
		return false, err
	}

	caKey, err := certutil.ParsePrivateKeyPEM(caKeyBytes)
	if err != nil {
		return false, err
	}

	caCert, err := certutil.ParseCertsPEM(caBytes)
	if err != nil {
		return false, err
	}

	keyBytes, _, err := certutil.LoadOrGenerateKeyFile(keyFile, regen)
	if err != nil {
		return false, err
	}

	key, err := certutil.ParsePrivateKeyPEM(keyBytes)
	if err != nil {
		return false, err
	}

	cfg := certutil.Config{
		CommonName:   commonName,
		Organization: organization,
		Usages:       extKeyUsage,
	}
	if altNames != nil {
		cfg.AltNames = *altNames
	}
	cert, err := certutil.NewSignedCert(cfg, key.(crypto.Signer), caCert[0], caKey.(crypto.Signer))
	if err != nil {
		return false, err
	}

	return true, certutil.WriteCert(certFile, append(certutil.EncodeCertPEM(cert), certutil.EncodeCertPEM(caCert[0])...))
}

func exists(files ...string) bool {
	for _, file := range files {
		if _, err := os.Stat(file); err != nil {
			return false
		}
	}
	return true
}

func genServiceAccount(runtime *config.ControlRuntime) error {
	_, keyErr := os.Stat(runtime.ServiceKey)
	if keyErr == nil {
		return nil
	}

	key, err := certutil.NewPrivateKey()
	if err != nil {
		return err
	}

	return certutil.WriteKey(runtime.ServiceKey, certutil.EncodePrivateKeyPEM(key))
}

func createSigningCertKey(prefix, certFile, keyFile string) (bool, error) {
	if exists(certFile, keyFile) {
		return false, nil
	}

	caKeyBytes, _, err := certutil.LoadOrGenerateKeyFile(keyFile, false)
	if err != nil {
		return false, err
	}

	caKey, err := certutil.ParsePrivateKeyPEM(caKeyBytes)
	if err != nil {
		return false, err
	}

	cfg := certutil.Config{
		CommonName: fmt.Sprintf("%s-ca@%d", prefix, time.Now().Unix()),
	}

	cert, err := certutil.NewSelfSignedCACert(cfg, caKey.(crypto.Signer))
	if err != nil {
		return false, err
	}

	if err := certutil.WriteCert(certFile, certutil.EncodeCertPEM(cert)); err != nil {
		return false, err
	}
	return true, nil
}

func KubeConfig(dest, url, caCert, clientCert, clientKey string) error {
	data := struct {
		URL        string
		CACert     string
		ClientCert string
		ClientKey  string
	}{
		URL:        url,
		CACert:     caCert,
		ClientCert: clientCert,
		ClientKey:  clientKey,
	}

	output, err := os.Create(dest)
	if err != nil {
		return err
	}
	defer output.Close()

	return kubeconfigTemplate.Execute(output, &data)
}

func setupStorageBackend(argsMap map[string]string, cfg *config.Control) {
	argsMap["storage-backend"] = "etcd3"
	// specify the endpoints
	if len(cfg.Datastore.Endpoint) > 0 {
		argsMap["etcd-servers"] = cfg.Datastore.Endpoint
	}
	// storage backend tls configuration
	if len(cfg.Datastore.CAFile) > 0 {
		argsMap["etcd-cafile"] = cfg.Datastore.CAFile
	}
	if len(cfg.Datastore.CertFile) > 0 {
		argsMap["etcd-certfile"] = cfg.Datastore.CertFile
	}
	if len(cfg.Datastore.KeyFile) > 0 {
		argsMap["etcd-keyfile"] = cfg.Datastore.KeyFile
	}
}

func sansChanged(certFile string, sans *certutil.AltNames) bool {
	if sans == nil {
		return false
	}

	certBytes, err := ioutil.ReadFile(certFile)
	if err != nil {
		return false
	}

	certificates, err := certutil.ParseCertsPEM(certBytes)
	if err != nil {
		return false
	}

	if len(certificates) == 0 {
		return false
	}

	if !sets.NewString(certificates[0].DNSNames...).HasAll(sans.DNSNames...) {
		return true
	}

	ips := sets.NewString()
	for _, ip := range certificates[0].IPAddresses {
		ips.Insert(ip.String())
	}

	for _, ip := range sans.IPs {
		if !ips.Has(ip.String()) {
			return true
		}
	}

	return false
}

func expired(certFile string, pool *x509.CertPool) bool {
	certBytes, err := ioutil.ReadFile(certFile)
	if err != nil {
		return false
	}
	certificates, err := certutil.ParseCertsPEM(certBytes)
	if err != nil {
		return false
	}
	_, err = certificates[0].Verify(x509.VerifyOptions{
		Roots: pool,
		KeyUsages: []x509.ExtKeyUsage{
			x509.ExtKeyUsageAny,
		},
	})
	if err != nil {
		return true
	}
	return certutil.IsCertExpired(certificates[0], config.CertificateRenewDays)
}

func cloudControllerManager(ctx context.Context, cfg *config.Control, runtime *config.ControlRuntime) {
	// Reference: https://github.com/kubernetes/kubernetes/pull/93764
	// The above-linked change made the in-tree cloud-controller-manager command much more flexible
	// but much more complicated to wrap. It now validates some of the configuration very early on, before
	// the CLI args are parsed, so some of the configuration needs to be hardcoded instead of set via flags.

	argsMap := map[string]string{
		"profiling": "false",
	}
	args := config.GetArgsList(argsMap, cfg.ExtraCloudControllerArgs)

	s, err := ccmopt.NewCloudControllerManagerOptions()
	if err != nil {
		logrus.Fatalf("Unable to initialize cloudcontroller options: %v", err)
	}

	s.KubeCloudShared.AllocateNodeCIDRs = true
	s.KubeCloudShared.CloudProvider.Name = version.Program
	s.KubeCloudShared.ClusterCIDR = cfg.ClusterIPRange.String()
	s.KubeCloudShared.ConfigureCloudRoutes = false
	s.Kubeconfig = runtime.KubeConfigCloudController
	s.NodeStatusUpdateFrequency = metav1.Duration{Duration: 1 * time.Minute}
	s.SecureServing.BindAddress = localhostIP
	s.SecureServing.BindPort = 0

	if cfg.NoLeaderElect {
		s.Generic.LeaderElection.LeaderElect = false
	}

	c, err := s.Config([]string{}, []string{})
	if err != nil {
		logrus.Fatalf("Unable to create cloudcontroller config from options: %v", err)
	}

	cloud, err := ccm.InitCloudProvider(version.Program, runtime.KubeConfigCloudController)
	if err != nil {
		logrus.Fatalf("Cloud provider could not be initialized: %v", err)
	}
	if cloud == nil {
		logrus.Fatalf("Cloud provider is nil")
	}

	cloud.Initialize(c.ClientBuilder, make(chan struct{}))
	if informerUserCloud, ok := cloud.(ccm.InformerUser); ok {
		informerUserCloud.SetInformers(c.SharedInformers)
	}

	controllerInitializers := ccmapp.DefaultControllerInitializers(c.Complete(), cloud)
	delete(controllerInitializers, "service")
	delete(controllerInitializers, "route")

	command := ccmapp.NewCloudControllerManagerCommand(s, c, controllerInitializers)
	command.SetArgs(args)
	// register k3s cloud provider

	go func() {
		for {
			// check for the cloud controller rbac binding
			if err := checkForCloudControllerPrivileges(runtime); err != nil {
				logrus.Infof("Waiting for cloudcontroller rbac role to be created")
				select {
				case <-ctx.Done():
					logrus.Fatalf("cloud-controller-manager context canceled: %v", ctx.Err())
				case <-time.After(time.Second):
					continue
				}
			}
			break
		}
		logrus.Infof("Running cloud-controller-manager for provider %v with args %v", cloud.ProviderName(), config.ArgString(args))
		logrus.Fatalf("cloud-controller-manager exited: %v", command.ExecuteContext(ctx))
	}()
}

func checkForCloudControllerPrivileges(runtime *config.ControlRuntime) error {
	restConfig, err := clientcmd.BuildConfigFromFlags("", runtime.KubeConfigAdmin)
	if err != nil {
		return err
	}
	crb := rbac.NewFactoryFromConfigOrDie(restConfig).Rbac().V1().ClusterRoleBinding()
	_, err = crb.Get("cloud-controller-manager", metav1.GetOptions{})
	if err != nil {
		return err
	}
	return nil
}

func waitForAPIServerInBackground(ctx context.Context, runtime *config.ControlRuntime) error {
	restConfig, err := clientcmd.BuildConfigFromFlags("", runtime.KubeConfigAdmin)
	if err != nil {
		return err
	}

	k8sClient, err := kubernetes.NewForConfig(restConfig)
	if err != nil {
		return err
	}

	done := make(chan struct{})
	runtime.APIServerReady = done

	go func() {
		defer close(done)

	etcdLoop:
		for {
			select {
			case <-ctx.Done():
				return
			case <-runtime.ETCDReady:
				break etcdLoop
			case <-time.After(30 * time.Second):
				logrus.Infof("Waiting for etcd server to become available")
			}
		}

		logrus.Infof("Waiting for API server to become available")
		for {
			select {
			case <-ctx.Done():
				return
			case err := <-promise(func() error { return app2.WaitForAPIServer(k8sClient, 30*time.Second) }):
				if err != nil {
					logrus.Infof("Waiting for API server to become available")
					continue
				}
				return
			}
		}
	}()

	return nil
}

func promise(f func() error) <-chan error {
	c := make(chan error, 1)
	go func() {
		c <- f()
		close(c)
	}()
	return c
}

func genEncryptionConfig(controlConfig *config.Control, runtime *config.ControlRuntime) error {
	if !controlConfig.EncryptSecrets {
		return nil
	}
	if s, err := os.Stat(runtime.EncryptionConfig); err == nil && s.Size() > 0 {
		return nil
	}

	aescbcKey := make([]byte, aescbcKeySize, aescbcKeySize)
	_, err := cryptorand.Read(aescbcKey)
	if err != nil {
		return err
	}
	encodedKey := b64.StdEncoding.EncodeToString(aescbcKey)

	encConfig := apiserverconfigv1.EncryptionConfiguration{
		TypeMeta: metav1.TypeMeta{
			Kind:       "EncryptionConfiguration",
			APIVersion: "apiserver.config.k8s.io/v1",
		},
		Resources: []apiserverconfigv1.ResourceConfiguration{
			{
				Resources: []string{"secrets"},
				Providers: []apiserverconfigv1.ProviderConfiguration{
					{
						AESCBC: &apiserverconfigv1.AESConfiguration{
							Keys: []apiserverconfigv1.Key{
								{
									Name:   "aescbckey",
									Secret: encodedKey,
								},
							},
						},
					},
					{
						Identity: &apiserverconfigv1.IdentityConfiguration{},
					},
				},
			},
		},
	}
	jsonfile, err := json.Marshal(encConfig)
	if err != nil {
		return err
	}
	return ioutil.WriteFile(runtime.EncryptionConfig, jsonfile, 0600)
}