/*

 Copyright 2019 The KubeSphere 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 kubectl

import (
	"fmt"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes"
	"k8s.io/klog"
	"kubesphere.io/kubesphere/pkg/models"
	"math/rand"
	"os"

	appsv1 "k8s.io/api/apps/v1"
	"k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"

	"k8s.io/apimachinery/pkg/api/errors"

	"kubesphere.io/kubesphere/pkg/constants"
)

const (
	namespace = constants.KubeSphereControlNamespace
)

type Interface interface {
	GetKubectlPod(username string) (models.PodInfo, error)
	CreateKubectlDeploy(username string) error
	DelKubectlDeploy(username string) error
}

type operator struct {
	k8sClient kubernetes.Interface
	informers informers.SharedInformerFactory
}

func NewKubectlOperator(k8sClient kubernetes.Interface, informers informers.SharedInformerFactory) Interface {
	return &operator{k8sClient: k8sClient, informers: informers}
}

var DefaultImage = "kubesphere/kubectl:advanced-1.0.0"

func init() {
	if env := os.Getenv("KUBECTL_IMAGE"); env != "" {
		DefaultImage = env
	}
}

func (o *operator) GetKubectlPod(username string) (models.PodInfo, error) {
	deployName := fmt.Sprintf("kubectl-%s", username)
	deploy, err := o.informers.Apps().V1().Deployments().Lister().Deployments(namespace).Get(deployName)
	if err != nil {
		klog.Errorln(err)
		return models.PodInfo{}, err
	}

	selectors := deploy.Spec.Selector.MatchLabels
	labelSelector := labels.Set(selectors).AsSelector()
	pods, err := o.informers.Core().V1().Pods().Lister().Pods(namespace).List(labelSelector)
	if err != nil {
		klog.Errorln(err)
		return models.PodInfo{}, err
	}

	pod, err := selectCorrectPod(namespace, pods)
	if err != nil {
		klog.Errorln(err)
		return models.PodInfo{}, err
	}

	info := models.PodInfo{Namespace: pod.Namespace, Pod: pod.Name, Container: pod.Status.ContainerStatuses[0].Name}

	return info, nil

}

func selectCorrectPod(namespace string, pods []*v1.Pod) (kubectlPod *v1.Pod, err error) {

	var kubectlPodList []*v1.Pod
	for _, pod := range pods {
		for _, condition := range pod.Status.Conditions {
			if condition.Type == "Ready" && condition.Status == "True" {
				kubectlPodList = append(kubectlPodList, pod)
			}
		}
	}
	if len(kubectlPodList) < 1 {
		err = fmt.Errorf("cannot find valid kubectl pod in namespace:%s", namespace)
		return &v1.Pod{}, err
	}

	random := rand.Intn(len(kubectlPodList))

	return kubectlPodList[random], nil
}

func (o *operator) CreateKubectlDeploy(username string) error {
	k8sClient := o.k8sClient
	deployName := fmt.Sprintf("kubectl-%s", username)
	_, err := k8sClient.AppsV1().Deployments(namespace).Get(deployName, metav1.GetOptions{})
	if err == nil {
		return nil
	}

	replica := int32(1)
	selector := metav1.LabelSelector{MatchLabels: map[string]string{"username": username}}
	deployment := appsv1.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name: deployName,
		},
		Spec: appsv1.DeploymentSpec{
			Replicas: &replica,
			Selector: &selector,
			Template: v1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: map[string]string{
						"username": username,
					},
				},
				Spec: v1.PodSpec{
					Containers: []v1.Container{
						{Name: "kubectl",
							Image: DefaultImage,
						},
					},
					ServiceAccountName: "kubesphere-cluster-admin",
				},
			},
		},
	}

	_, err = k8sClient.AppsV1().Deployments(namespace).Create(&deployment)

	return err
}

func (o *operator) DelKubectlDeploy(username string) error {
	k8sClient := o.k8sClient
	deployName := fmt.Sprintf("kubectl-%s", username)
	_, err := k8sClient.AppsV1().Deployments(namespace).Get(deployName, metav1.GetOptions{})
	if errors.IsNotFound(err) {
		return nil
	}

	if err != nil {
		err := fmt.Errorf("delete username %s failed, reason:%v", username, err)
		return err
	}

	deletePolicy := metav1.DeletePropagationBackground

	err = k8sClient.AppsV1().Deployments(namespace).Delete(deployName, &metav1.DeleteOptions{PropagationPolicy: &deletePolicy})
	if err != nil {
		err := fmt.Errorf("delete username %s failed, reason:%v", username, err)
		return err
	}

	return nil
}
