package e2e

import (
	"context"
	"fmt"
	"strings"

	"github.com/onsi/ginkgo"
	"github.com/onsi/gomega"
	appsv1 "k8s.io/api/apps/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/rand"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/klog/v2"
	"sigs.k8s.io/controller-runtime/pkg/client"

	clusterv1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
	policyv1alpha1 "github.com/karmada-io/karmada/pkg/apis/policy/v1alpha1"
	workv1alpha2 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha2"
	"github.com/karmada-io/karmada/pkg/util"
	"github.com/karmada-io/karmada/pkg/util/helper"
	"github.com/karmada-io/karmada/pkg/util/names"
	"github.com/karmada-io/karmada/test/e2e/framework"
	testhelper "github.com/karmada-io/karmada/test/helper"
)

// failover testing is used to test the rescheduling situation when some initially scheduled clusters fail
var _ = ginkgo.Describe("failover testing", func() {
	ginkgo.Context("Deployment propagation testing", func() {
		var disabledClusters []*clusterv1alpha1.Cluster
		policyNamespace := testNamespace
		policyName := deploymentNamePrefix + rand.String(RandomStrLength)
		deploymentNamespace := testNamespace
		deploymentName := policyName
		deployment := testhelper.NewDeployment(deploymentNamespace, deploymentName)
		maxGroups := 1
		minGroups := 1
		numOfFailedClusters := 1

		// targetClusterNames is a slice of cluster names in resource binding
		var targetClusterNames []string

		// set MaxGroups=MinGroups=1, label is location=CHN.
		policy := testhelper.NewPropagationPolicy(policyNamespace, policyName, []policyv1alpha1.ResourceSelector{
			{
				APIVersion: deployment.APIVersion,
				Kind:       deployment.Kind,
				Name:       deployment.Name,
			},
		}, policyv1alpha1.Placement{
			ClusterAffinity: &policyv1alpha1.ClusterAffinity{
				LabelSelector: &metav1.LabelSelector{
					// only test push mode clusters
					// because pull mode clusters cannot be disabled by changing APIEndpoint
					MatchLabels: pushModeClusterLabels,
				},
			},
			SpreadConstraints: []policyv1alpha1.SpreadConstraint{
				{
					SpreadByField: policyv1alpha1.SpreadByFieldCluster,
					MaxGroups:     maxGroups,
					MinGroups:     minGroups,
				},
			},
		})

		ginkgo.It("deployment failover testing", func() {
			framework.CreatePropagationPolicy(karmadaClient, policy)
			framework.CreateDeployment(kubeClient, deployment)

			fmt.Printf("View the results of the initial scheduling")
			targetClusterNames, _ = getTargetClusterNames(deployment)
			for _, clusterName := range targetClusterNames {
				fmt.Printf("%s is the target cluster\n", clusterName)
			}

			ginkgo.By("set one cluster condition status to false", func() {
				temp := numOfFailedClusters
				for _, targetClusterName := range targetClusterNames {
					if temp > 0 {
						err := disableCluster(controlPlaneClient, targetClusterName)
						gomega.Expect(err).ShouldNot(gomega.HaveOccurred())

						fmt.Printf("cluster %s is false\n", targetClusterName)

						// wait for the current cluster status changing to false
						err = wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
							currentCluster, err := util.GetCluster(controlPlaneClient, targetClusterName)
							if err != nil {
								return false, err
							}
							if meta.IsStatusConditionPresentAndEqual(currentCluster.Status.Conditions, clusterv1alpha1.ClusterConditionReady, metav1.ConditionFalse) {
								fmt.Printf("current cluster %s is false\n", targetClusterName)
								disabledClusters = append(disabledClusters, currentCluster)
								return true, nil
							}
							return false, nil
						})
						gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
						temp--
					}
				}
			})

			ginkgo.By("check whether deployment of failed cluster is rescheduled to other available cluster", func() {
				totalNum := 0

				targetClusterNames, err := getTargetClusterNames(deployment)
				gomega.Expect(err).ShouldNot(gomega.HaveOccurred())

				for _, targetClusterName := range targetClusterNames {
					// the target cluster should be overwritten to another available cluster
					gomega.Expect(isDisabled(targetClusterName, disabledClusters)).Should(gomega.BeFalse())

					clusterClient := framework.GetClusterClient(targetClusterName)
					gomega.Expect(clusterClient).ShouldNot(gomega.BeNil())

					klog.Infof("Check whether deployment(%s/%s) is present on cluster(%s)", deploymentNamespace, deploymentName, targetClusterName)
					err := wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
						_, err = clusterClient.AppsV1().Deployments(deploymentNamespace).Get(context.TODO(), deploymentName, metav1.GetOptions{})
						if err != nil {
							if apierrors.IsNotFound(err) {
								return false, nil
							}
							return false, err
						}
						fmt.Printf("Deployment(%s/%s) is present on cluster(%s).\n", deploymentNamespace, deploymentName, targetClusterName)
						return true, nil
					})
					gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
					totalNum++
					gomega.Expect(totalNum == minGroups).Should(gomega.BeTrue())
				}
				fmt.Printf("reschedule in %d target cluster\n", totalNum)
			})

			ginkgo.By("check if the scheduled condition is true", func() {
				err := wait.PollImmediate(pollInterval, pollTimeout, func() (bool, error) {
					rb, err := getResourceBinding(deployment)
					gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
					return meta.IsStatusConditionTrue(rb.Status.Conditions, workv1alpha2.Scheduled), nil
				})
				gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
			})

			ginkgo.By("recover not ready cluster", func() {
				for _, disabledCluster := range disabledClusters {
					fmt.Printf("cluster %s is waiting for recovering\n", disabledCluster.Name)
					originalAPIEndpoint := getClusterAPIEndpoint(disabledCluster.Name)

					err := recoverCluster(controlPlaneClient, disabledCluster.Name, originalAPIEndpoint)
					gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
					// wait for the disabled cluster recovered
					err = wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
						currentCluster, err := util.GetCluster(controlPlaneClient, disabledCluster.Name)
						if err != nil {
							return false, err
						}
						if meta.IsStatusConditionPresentAndEqual(currentCluster.Status.Conditions, clusterv1alpha1.ClusterConditionReady, metav1.ConditionTrue) {
							fmt.Printf("cluster %s recovered\n", disabledCluster.Name)
							return true, nil
						}
						return false, nil
					})
					gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
				}
			})

			framework.RemoveDeployment(kubeClient, deployment.Namespace, deployment.Name)
			framework.RemovePropagationPolicy(karmadaClient, policy.Namespace, policy.Name)
		})
	})
})

// disableCluster will set wrong API endpoint of current cluster
func disableCluster(c client.Client, clusterName string) error {
	err := wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
		clusterObj := &clusterv1alpha1.Cluster{}
		if err := c.Get(context.TODO(), client.ObjectKey{Name: clusterName}, clusterObj); err != nil {
			if apierrors.IsConflict(err) {
				return false, nil
			}
			return false, err
		}
		// set the APIEndpoint of matched cluster to a wrong value
		unavailableAPIEndpoint := "https://172.19.1.3:6443"
		clusterObj.Spec.APIEndpoint = unavailableAPIEndpoint
		if err := c.Update(context.TODO(), clusterObj); err != nil {
			if apierrors.IsConflict(err) {
				return false, nil
			}
			return false, err
		}
		return true, nil
	})
	return err
}

// recoverCluster will recover API endpoint of the disable cluster
func recoverCluster(c client.Client, clusterName string, originalAPIEndpoint string) error {
	err := wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
		clusterObj := &clusterv1alpha1.Cluster{}
		if err := c.Get(context.TODO(), client.ObjectKey{Name: clusterName}, clusterObj); err != nil {
			return false, err
		}
		clusterObj.Spec.APIEndpoint = originalAPIEndpoint
		if err := c.Update(context.TODO(), clusterObj); err != nil {
			if apierrors.IsConflict(err) {
				return false, nil
			}
			return false, err
		}
		fmt.Printf("recovered API endpoint is %s\n", clusterObj.Spec.APIEndpoint)
		return true, nil
	})
	return err
}

// get the target cluster names from binding information
func getTargetClusterNames(deployment *appsv1.Deployment) (targetClusterNames []string, err error) {
	bindingName := names.GenerateBindingName(deployment.Kind, deployment.Name)
	binding := &workv1alpha2.ResourceBinding{}

	err = wait.PollImmediate(pollInterval, pollTimeout, func() (done bool, err error) {
		err = controlPlaneClient.Get(context.TODO(), client.ObjectKey{Namespace: deployment.Namespace, Name: bindingName}, binding)
		if err != nil {
			if apierrors.IsNotFound(err) {
				return false, nil
			}
			return false, err
		}

		if !helper.IsBindingReady(&binding.Status) {
			klog.Infof("The ResourceBinding(%s/%s) hasn't been scheduled.", binding.Namespace, binding.Name)
			return false, nil
		}

		return true, nil
	})
	if err != nil {
		return nil, err
	}
	for _, cluster := range binding.Spec.Clusters {
		targetClusterNames = append(targetClusterNames, cluster.Name)
	}
	klog.Infof("The ResourceBinding(%s/%s) schedule result is: %s", binding.Namespace, binding.Name, strings.Join(targetClusterNames, ","))
	return targetClusterNames, nil
}

// indicate if the cluster is disabled
func isDisabled(clusterName string, disabledClusters []*clusterv1alpha1.Cluster) bool {
	for _, cluster := range disabledClusters {
		if cluster.Name == clusterName {
			return true
		}
	}
	return false
}

// get the API endpoint of a specific cluster
func getClusterAPIEndpoint(clusterName string) (apiEndpoint string) {
	for _, cluster := range framework.Clusters() {
		if cluster.Name == clusterName {
			apiEndpoint = cluster.Spec.APIEndpoint
			fmt.Printf("original API endpoint of the cluster %s is %s\n", clusterName, apiEndpoint)
		}
	}
	return apiEndpoint
}