/*
Copyright 2016 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 master

import (
	"crypto/x509"
	"encoding/json"
	"fmt"
	"path"
	"runtime"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	kuberuntime "k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	clientset "k8s.io/client-go/kubernetes"
	"k8s.io/client-go/pkg/api"
	"k8s.io/client-go/pkg/api/v1"
	extensions "k8s.io/client-go/pkg/apis/extensions/v1beta1"
	certutil "k8s.io/client-go/util/cert"
	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
)

const (
	kubeDiscoverySecretName = "clusterinfo"
	kubeDiscoveryName       = "kube-discovery"
)

// TODO: Remove this file as soon as jbeda's token discovery refactoring PR has merged

func encodeKubeDiscoverySecretData(dcfg *kubeadmapi.TokenDiscovery, apicfg kubeadmapi.API, caCert *x509.Certificate) map[string][]byte {
	var (
		data         = map[string][]byte{}
		endpointList = []string{}
		tokenMap     = map[string]string{}
	)

	for _, addr := range apicfg.AdvertiseAddresses {
		endpointList = append(endpointList, fmt.Sprintf("https://%s:%d", addr, apicfg.Port))
	}

	tokenMap[dcfg.ID] = dcfg.Secret

	data["endpoint-list.json"], _ = json.Marshal(endpointList)
	data["token-map.json"], _ = json.Marshal(tokenMap)
	data["ca.pem"] = certutil.EncodeCertPEM(caCert)

	return data
}

func CreateDiscoveryDeploymentAndSecret(cfg *kubeadmapi.MasterConfiguration, client *clientset.Clientset) error {
	caCertificatePath := path.Join(kubeadmapi.GlobalEnvParams.HostPKIPath, kubeadmconstants.CACertName)
	caCerts, err := certutil.CertsFromFile(caCertificatePath)
	if err != nil {
		return fmt.Errorf("couldn't load the CA certificate file %s: %v", caCertificatePath, err)
	}

	// We are only putting one certificate in the certificate pem file, so it's safe to just pick the first one
	// TODO: Support multiple certs here in order to be able to rotate certs
	caCert := caCerts[0]

	secret := &v1.Secret{
		ObjectMeta: metav1.ObjectMeta{Name: kubeDiscoverySecretName},
		Type:       v1.SecretTypeOpaque,
		Data:       encodeKubeDiscoverySecretData(cfg.Discovery.Token, cfg.API, caCert),
	}
	if _, err := client.Secrets(metav1.NamespaceSystem).Create(secret); err != nil {
		return fmt.Errorf("failed to create %q secret [%v]", kubeDiscoverySecretName, err)
	}

	if err := createDiscoveryDeployment(client); err != nil {
		return err
	}

	fmt.Println("[token-discovery] Created the kube-discovery deployment, waiting for it to become ready")

	start := time.Now()
	wait.PollInfinite(kubeadmconstants.APICallRetryInterval, func() (bool, error) {
		d, err := client.Extensions().Deployments(metav1.NamespaceSystem).Get(kubeDiscoveryName, metav1.GetOptions{})
		if err != nil {
			return false, nil
		}
		if d.Status.AvailableReplicas < 1 {
			return false, nil
		}
		return true, nil
	})
	fmt.Printf("[token-discovery] kube-discovery is ready after %f seconds\n", time.Since(start).Seconds())

	return nil
}

func createDiscoveryDeployment(client *clientset.Clientset) error {
	discoveryBytes, err := kubeadmutil.ParseTemplate(KubeDiscoveryDeployment, struct{ ImageRepository, Arch string }{
		ImageRepository: kubeadmapi.GlobalEnvParams.RepositoryPrefix,
		Arch:            runtime.GOARCH,
	})
	if err != nil {
		return fmt.Errorf("error when parsing kube-discovery template: %v", err)
	}

	discoveryDeployment := &extensions.Deployment{}
	if err := kuberuntime.DecodeInto(api.Codecs.UniversalDecoder(), discoveryBytes, discoveryDeployment); err != nil {
		return fmt.Errorf("unable to decode kube-discovery deployment %v", err)
	}
	if _, err := client.ExtensionsV1beta1().Deployments(metav1.NamespaceSystem).Create(discoveryDeployment); err != nil {
		return fmt.Errorf("unable to create a new discovery deployment: %v", err)
	}
	return nil
}