package cmds

import (
	"context"
	"errors"
	"net/url"
	"strings"
	"time"

	"github.com/rancher/k3k/pkg/apis/k3k.io/v1alpha1"
	k3kcluster "github.com/rancher/k3k/pkg/controller/cluster"
	"github.com/rancher/k3k/pkg/controller/kubeconfig"
	"github.com/sirupsen/logrus"
	"github.com/urfave/cli/v2"
	v1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
	"k8s.io/client-go/util/retry"
	"k8s.io/utils/ptr"
)

type CreateConfig struct {
	token                string
	clusterCIDR          string
	serviceCIDR          string
	servers              int
	agents               int
	serverArgs           cli.StringSlice
	agentArgs            cli.StringSlice
	serverEnvs           cli.StringSlice
	agentEnvs            cli.StringSlice
	persistenceType      string
	storageClassName     string
	storageRequestSize   string
	version              string
	mode                 string
	kubeconfigServerHost string
	policy               string
}

func NewClusterCreateCmd(appCtx *AppContext) *cli.Command {
	createConfig := &CreateConfig{}

	flags := CommonFlags(appCtx)
	flags = append(flags, FlagNamespace(appCtx))
	flags = append(flags, newCreateFlags(createConfig)...)

	return &cli.Command{
		Name:            "create",
		Usage:           "Create new cluster",
		UsageText:       "k3kcli cluster create [command options] NAME",
		Action:          createAction(appCtx, createConfig),
		Flags:           flags,
		HideHelpCommand: true,
	}
}

func createAction(appCtx *AppContext, config *CreateConfig) cli.ActionFunc {
	return func(clx *cli.Context) error {
		ctx := context.Background()
		client := appCtx.Client

		if clx.NArg() != 1 {
			return cli.ShowSubcommandHelp(clx)
		}

		name := clx.Args().First()
		if name == k3kcluster.ClusterInvalidName {
			return errors.New("invalid cluster name")
		}

		if config.mode == string(v1alpha1.SharedClusterMode) && config.agents != 0 {
			return errors.New("invalid flag, --agents flag is only allowed in virtual mode")
		}

		namespace := appCtx.Namespace(name)

		if err := createNamespace(ctx, client, namespace, config.policy); err != nil {
			return err
		}

		if strings.Contains(config.version, "+") {
			orig := config.version
			config.version = strings.Replace(config.version, "+", "-", -1)
			logrus.Warnf("Invalid K3s docker reference version: '%s'. Using '%s' instead", orig, config.version)
		}

		if config.token != "" {
			logrus.Info("Creating cluster token secret")

			obj := k3kcluster.TokenSecretObj(config.token, name, namespace)

			if err := client.Create(ctx, &obj); err != nil {
				return err
			}
		}

		logrus.Infof("Creating cluster [%s] in namespace [%s]", name, namespace)

		cluster := newCluster(name, namespace, config)

		cluster.Spec.Expose = &v1alpha1.ExposeConfig{
			NodePort: &v1alpha1.NodePortConfig{},
		}

		// add Host IP address as an extra TLS-SAN to expose the k3k cluster
		url, err := url.Parse(appCtx.RestConfig.Host)
		if err != nil {
			return err
		}

		host := strings.Split(url.Host, ":")
		if config.kubeconfigServerHost != "" {
			host = []string{config.kubeconfigServerHost}
		}

		cluster.Spec.TLSSANs = []string{host[0]}

		if err := client.Create(ctx, cluster); err != nil {
			if apierrors.IsAlreadyExists(err) {
				logrus.Infof("Cluster [%s] already exists", name)
			} else {
				return err
			}
		}

		logrus.Infof("Extracting Kubeconfig for [%s] cluster", name)

		logrus.Infof("waiting for cluster to be available..")

		// retry every 5s for at most 2m, or 25 times
		availableBackoff := wait.Backoff{
			Duration: 5 * time.Second,
			Cap:      2 * time.Minute,
			Steps:    25,
		}

		cfg := kubeconfig.New()

		var kubeconfig *clientcmdapi.Config

		if err := retry.OnError(availableBackoff, apierrors.IsNotFound, func() error {
			kubeconfig, err = cfg.Generate(ctx, client, cluster, host[0])
			return err
		}); err != nil {
			return err
		}

		return writeKubeconfigFile(cluster, kubeconfig)
	}
}

func newCluster(name, namespace string, config *CreateConfig) *v1alpha1.Cluster {
	cluster := &v1alpha1.Cluster{
		ObjectMeta: metav1.ObjectMeta{
			Name:      name,
			Namespace: namespace,
		},
		TypeMeta: metav1.TypeMeta{
			Kind:       "Cluster",
			APIVersion: "k3k.io/v1alpha1",
		},
		Spec: v1alpha1.ClusterSpec{
			Servers:     ptr.To(int32(config.servers)),
			Agents:      ptr.To(int32(config.agents)),
			ClusterCIDR: config.clusterCIDR,
			ServiceCIDR: config.serviceCIDR,
			ServerArgs:  config.serverArgs.Value(),
			AgentArgs:   config.agentArgs.Value(),
			ServerEnvs:  env(config.serverEnvs.Value()),
			AgentEnvs:   env(config.agentEnvs.Value()),
			Version:     config.version,
			Mode:        v1alpha1.ClusterMode(config.mode),
			Persistence: v1alpha1.PersistenceConfig{
				Type:               v1alpha1.PersistenceMode(config.persistenceType),
				StorageClassName:   ptr.To(config.storageClassName),
				StorageRequestSize: config.storageRequestSize,
			},
		},
	}
	if config.storageClassName == "" {
		cluster.Spec.Persistence.StorageClassName = nil
	}

	if config.token != "" {
		cluster.Spec.TokenSecretRef = &v1.SecretReference{
			Name:      k3kcluster.TokenSecretName(name),
			Namespace: namespace,
		}
	}

	return cluster
}

func env(envSlice []string) []v1.EnvVar {
	var envVars []v1.EnvVar

	for _, env := range envSlice {
		keyValue := strings.Split(env, "=")
		if len(keyValue) != 2 {
			logrus.Fatalf("incorrect value for environment variable %s", env)
		}

		envVars = append(envVars, v1.EnvVar{
			Name:  keyValue[0],
			Value: keyValue[1],
		})
	}

	return envVars
}