// RAINBOND, Application Management Platform
// Copyright (C) 2014-2017 Goodrain Co., Ltd.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version. For any non-GPL usage of Rainbond,
// one or multiple Commercial Licenses authorized by Goodrain Co., Ltd.
// must be obtained first.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.

package kubecache

import (
	"fmt"
	"math"
	"time"

	"github.com/pquerna/ffjson/ffjson"

	conf "github.com/goodrain/rainbond/cmd/node/option"
	"github.com/goodrain/rainbond/node/nodem/client"

	"github.com/Sirupsen/logrus"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/pkg/api/v1"
	policy "k8s.io/client-go/pkg/apis/policy/v1beta1"
	"k8s.io/client-go/tools/clientcmd"
)

const (
	//EvictionKind EvictionKind
	EvictionKind = "Eviction"
	//EvictionSubresource EvictionSubresource
	EvictionSubresource = "pods/eviction"
)

//KubeClient KubeClient
type KubeClient interface {
	UpK8sNode(*client.HostNode) (*v1.Node, error)
	DownK8sNode(nodename string) error
	GetAllPods() (pods []*v1.Pod, err error)
	GetPods(namespace string) (pods []*v1.Pod, err error)
	GetNodeByName(nodename string) (*v1.Node, error)
	GetNodes() ([]*v1.Node, error)
	GetNode(nodeName string) (*v1.Node, error)
	CordonOrUnCordon(nodeName string, drain bool) (*v1.Node, error)
	UpdateLabels(nodeName string, labels map[string]string) (*v1.Node, error)
	DeleteOrEvictPodsSimple(nodeName string) error
	GetPodsByNodes(nodeName string) (pods []v1.Pod, err error)
	GetEndpoints(namespace string, selector labels.Selector) ([]*v1.Endpoints, error)
	GetServices(namespace string, selector labels.Selector) ([]*v1.Service, error)
	Stop()
}

//NewKubeClient NewKubeClient
func NewKubeClient(cfg *conf.Conf) (KubeClient, error) {
	config, err := clientcmd.BuildConfigFromFlags("", cfg.K8SConfPath)
	if err != nil {
		return nil, err
	}
	config.QPS = 50
	config.Burst = 100
	cli, err := kubernetes.NewForConfig(config)
	if err != nil {
		return nil, err
	}
	stop := make(chan struct{})
	sharedInformers := informers.NewSharedInformerFactory(cli, cfg.MinResyncPeriod)
	sharedInformers.Core().V1().Services().Informer()
	sharedInformers.Core().V1().Endpoints().Informer()
	sharedInformers.Core().V1().Nodes().Informer()
	sharedInformers.Core().V1().Pods().Informer()
	sharedInformers.Start(stop)
	return &kubeClient{
		kubeclient:      cli,
		stop:            stop,
		sharedInformers: sharedInformers,
	}, nil
}

type kubeClient struct {
	kubeclient      *kubernetes.Clientset
	sharedInformers informers.SharedInformerFactory
	stop            chan struct{}
}

func (k *kubeClient) Stop() {
	if k.stop != nil {
		close(k.stop)
	}
}

//GetNodeByName get node
func (k *kubeClient) GetNodeByName(nodename string) (*v1.Node, error) {
	return k.sharedInformers.Core().V1().Nodes().Lister().Get(nodename)
}

//CordonOrUnCordon node scheduler
// drain:true can't scheduler ,false can scheduler
func (k *kubeClient) CordonOrUnCordon(nodeName string, drain bool) (*v1.Node, error) {
	data := fmt.Sprintf(`{"spec":{"unschedulable":%t}}`, drain)
	node, err := k.kubeclient.CoreV1().Nodes().Patch(nodeName, types.StrategicMergePatchType, []byte(data))
	if err != nil {
		return node, err
	}
	return node, nil
}

//UpdateLabels update lables
func (k *kubeClient) UpdateLabels(nodeName string, labels map[string]string) (*v1.Node, error) {
	labelStr, err := ffjson.Marshal(labels)
	if err != nil {
		return nil, err
	}
	data := fmt.Sprintf(`{"metadata":{"labels":%s}}`, string(labelStr))
	node, err := k.kubeclient.CoreV1().Nodes().Patch(nodeName, types.StrategicMergePatchType, []byte(data))
	if err != nil {
		return node, err
	}
	return node, nil
}

//DeleteOrEvictPodsSimple Evict the Pod from a node
func (k *kubeClient) DeleteOrEvictPodsSimple(nodeName string) error {
	pods, err := k.GetPodsByNodes(nodeName)
	if err != nil {
		logrus.Infof("get pods of node %s failed ", nodeName)
		return err
	}
	policyGroupVersion, err := k.SupportEviction()
	if err != nil {
		return err
	}
	if policyGroupVersion == "" {
		return fmt.Errorf("the server can not support eviction subresource")
	}
	for _, v := range pods {
		k.evictPod(v, policyGroupVersion)
	}
	return nil
}
func (k *kubeClient) GetPodsByNodes(nodeName string) (pods []v1.Pod, err error) {
	podList, err := k.kubeclient.Core().Pods(metav1.NamespaceAll).List(metav1.ListOptions{
		FieldSelector: fields.SelectorFromSet(fields.Set{"spec.nodeName": nodeName}).String()})
	if err != nil {
		return pods, err
	}
	for _, pod := range podList.Items {
		pods = append(pods, pod)
	}
	return pods, nil
}

//evictPod 驱离POD
func (k *kubeClient) evictPod(pod v1.Pod, policyGroupVersion string) error {
	deleteOptions := &metav1.DeleteOptions{}
	//if o.GracePeriodSeconds >= 0 {
	//	gracePeriodSeconds := int64(o.GracePeriodSeconds)
	//	deleteOptions.GracePeriodSeconds = &gracePeriodSeconds
	//}

	eviction := &policy.Eviction{
		///Users/goodrain/go/src/k8s.io/kubernetes/pkg/apis/policy/types.go
		///Users/goodrain/go/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go
		TypeMeta: metav1.TypeMeta{
			APIVersion: policyGroupVersion,
			Kind:       EvictionKind,
		},
		ObjectMeta: metav1.ObjectMeta{
			Name:      pod.Name,
			Namespace: pod.Namespace,
		},
		DeleteOptions: deleteOptions,
	}
	// Remember to change change the URL manipulation func when Evction's version change
	return k.kubeclient.Policy().Evictions(eviction.Namespace).Evict(eviction)
}

// deleteOrEvictPods deletes or evicts the pods on the api server
func (k *kubeClient) deleteOrEvictPods(pods []v1.Pod) error {
	if len(pods) == 0 {
		return nil
	}
	policyGroupVersion, err := k.SupportEviction()
	if err != nil {
		return err
	}
	getPodFn := func(namespace, name string) (*v1.Pod, error) {
		return k.kubeclient.CoreV1().Pods(namespace).Get(name, metav1.GetOptions{})
	}

	return k.evictPods(pods, policyGroupVersion, getPodFn)
	//if len(policyGroupVersion) > 0 {
	//	//return evictPods(pods, policyGroupVersion, getPodFn)
	//} else {
	//	return deletePods(pods, getPodFn)
	//}
}

func (k *kubeClient) deletePods(pods []v1.Pod, getPodFn func(namespace, name string) (*v1.Pod, error)) error {
	// 0 timeout means infinite, we use MaxInt64 to represent it.
	var globalTimeout time.Duration
	if conf.Config.ReqTimeout == 0 {
		//if Timeout == 0 {
		globalTimeout = time.Duration(math.MaxInt64)
	} else {
		globalTimeout = 1
		//globalTimeout = Timeout
	}
	for _, pod := range pods {
		err := k.deletePod(pod)
		if err != nil && !apierrors.IsNotFound(err) {
			return err
		}
	}
	_, err := waitForDelete(pods, time.Second*1, globalTimeout, false, getPodFn)
	return err
}
func waitForDelete(pods []v1.Pod, interval, timeout time.Duration, usingEviction bool, getPodFn func(string, string) (*v1.Pod, error)) ([]v1.Pod, error) {
	var verbStr string
	if usingEviction {
		verbStr = "evicted"
	} else {
		verbStr = "deleted"
	}
	err := wait.PollImmediate(interval, timeout, func() (bool, error) {
		pendingPods := []v1.Pod{}
		for i, pod := range pods {
			p, err := getPodFn(pod.Namespace, pod.Name)
			if apierrors.IsNotFound(err) || (p != nil && p.ObjectMeta.UID != pod.ObjectMeta.UID) {
				fmt.Println(verbStr)
				//cmdutil.PrintSuccess(o.mapper, false, o.Out, "pod", pod.Name, false, verbStr)//todo
				continue
			} else if err != nil {
				return false, err
			} else {
				pendingPods = append(pendingPods, pods[i])
			}
		}
		pods = pendingPods
		if len(pendingPods) > 0 {
			return false, nil
		}
		return true, nil
	})
	return pods, err
}
func (k *kubeClient) deletePod(pod v1.Pod) error {
	deleteOptions := &metav1.DeleteOptions{}
	//if GracePeriodSeconds >= 0 {
	//if 1 >= 0 {
	//	//gracePeriodSeconds := int64(GracePeriodSeconds)
	//	gracePeriodSeconds := int64(1)
	//	deleteOptions.GracePeriodSeconds = &gracePeriodSeconds
	//}
	gracePeriodSeconds := int64(1)
	deleteOptions.GracePeriodSeconds = &gracePeriodSeconds
	return k.kubeclient.CoreV1().Pods(pod.Namespace).Delete(pod.Name, deleteOptions)
}

func (k *kubeClient) evictPods(pods []v1.Pod, policyGroupVersion string, getPodFn func(namespace, name string) (*v1.Pod, error)) error {
	doneCh := make(chan bool, len(pods))
	errCh := make(chan error, 1)

	for _, pod := range pods {
		go func(pod v1.Pod, doneCh chan bool, errCh chan error) {
			var err error
			for {
				err = k.evictPod(pod, policyGroupVersion)
				if err == nil {
					break
				} else if apierrors.IsNotFound(err) {
					doneCh <- true
					return
				} else if apierrors.IsTooManyRequests(err) {
					time.Sleep(5 * time.Second)
				} else {
					errCh <- fmt.Errorf("error when evicting pod %q: %v", pod.Name, err)
					return
				}
			}
			podArray := []v1.Pod{pod}
			_, err = waitForDelete(podArray, time.Second*1, time.Duration(math.MaxInt64), true, getPodFn)
			if err == nil {
				doneCh <- true
			} else {
				errCh <- fmt.Errorf("error when waiting for pod %q terminating: %v", pod.Name, err)
			}
		}(pod, doneCh, errCh)
	}

	doneCount := 0
	// 0 timeout means infinite, we use MaxInt64 to represent it.
	var globalTimeout time.Duration
	globalTimeout = time.Duration(math.MaxInt64)
	//if conf.Config.ReqTimeout == 0 {
	//	//if Timeout == 0 {
	//	globalTimeout = time.Duration(math.MaxInt64)
	//} else {
	//	//globalTimeout = Timeout
	//	globalTimeout = 1000
	//}
	for {
		select {
		case err := <-errCh:
			return err
		case <-doneCh:
			doneCount++
			if doneCount == len(pods) {
				return nil
			}
		case <-time.After(globalTimeout):
			return fmt.Errorf("Drain did not complete within %v", globalTimeout)
		}
	}
}

// SupportEviction uses Discovery API to find out if the server support eviction subresource
// If support, it will return its groupVersion; Otherwise, it will return ""
func (k *kubeClient) SupportEviction() (string, error) {
	discoveryClient := k.kubeclient.Discovery()
	groupList, err := discoveryClient.ServerGroups()
	if err != nil {
		return "", err
	}
	foundPolicyGroup := false
	var policyGroupVersion string
	for _, group := range groupList.Groups {
		if group.Name == "policy" {
			foundPolicyGroup = true
			policyGroupVersion = group.PreferredVersion.GroupVersion
			break
		}
	}
	if !foundPolicyGroup {
		return "", nil
	}
	resourceList, err := discoveryClient.ServerResourcesForGroupVersion("v1")
	if err != nil {
		return "", err
	}
	for _, resource := range resourceList.APIResources {
		if resource.Name == EvictionSubresource && resource.Kind == EvictionKind {
			return policyGroupVersion, nil
		}
	}
	return "", nil
}

//GetAllPods get all pods
func (k *kubeClient) GetAllPods() (pods []*v1.Pod, err error) {
	podList, err := k.sharedInformers.Core().V1().Pods().Lister().List(labels.Everything())
	if err != nil {
		return pods, err
	}
	return podList, nil
}

//GetAllPods get all pods
func (k *kubeClient) GetPods(namespace string) (pods []*v1.Pod, err error) {
	podList, err := k.sharedInformers.Core().V1().Pods().Lister().Pods(namespace).List(labels.Everything())
	if err != nil {
		return pods, err
	}
	return podList, nil
}

//DeleteNode  k8s节点下线
func (k *kubeClient) DownK8sNode(nodename string) error {
	_, err := k.GetNodeByName(nodename)
	if err != nil {
		logrus.Infof("get k8s node %s failed ", nodename)
		return err
	}
	//节点禁止调度
	_, err = k.CordonOrUnCordon(nodename, true)
	if err != nil {
		logrus.Infof("cordon node %s failed ", nodename)
		return err
	}
	//节点pod驱离
	err = k.DeleteOrEvictPodsSimple(nodename)
	if err != nil {
		logrus.Infof("delete or evict pods of node  %s failed ", nodename)
		return err
	}
	//删除节点
	err = k.deleteNodeWithoutPods(nodename)
	if err != nil {
		logrus.Infof("delete node with given name failed  %s failed ", nodename)
		return err
	}
	return nil
}

func (k *kubeClient) deleteNodeWithoutPods(name string) error {
	opt := &metav1.DeleteOptions{}
	err := k.kubeclient.Nodes().Delete(name, opt)
	if err != nil {
		return err
	}
	return nil
}

//UpK8sNode create k8s node by rainbond node info
func (k *kubeClient) UpK8sNode(rainbondNode *client.HostNode) (*v1.Node, error) {
	capacity := make(v1.ResourceList)
	capacity[v1.ResourceCPU] = *resource.NewQuantity(rainbondNode.AvailableCPU, resource.BinarySI)
	capacity[v1.ResourceMemory] = *resource.NewQuantity(rainbondNode.AvailableMemory, resource.BinarySI)
	node := &v1.Node{
		ObjectMeta: metav1.ObjectMeta{
			Name:   rainbondNode.ID,
			Labels: rainbondNode.Labels,
		},
		Spec: v1.NodeSpec{
			Unschedulable: rainbondNode.Unschedulable,
		},
		Status: v1.NodeStatus{
			Capacity:    capacity,
			Allocatable: capacity,
			Addresses: []v1.NodeAddress{
				v1.NodeAddress{Type: v1.NodeHostName, Address: rainbondNode.HostName},
				v1.NodeAddress{Type: v1.NodeInternalIP, Address: rainbondNode.InternalIP},
				v1.NodeAddress{Type: v1.NodeExternalIP, Address: rainbondNode.ExternalIP},
			},
		},
	}
	savedNode, err := k.kubeclient.Nodes().Create(node)
	if err != nil {
		return nil, err
	}
	logrus.Info("creating new node success , details: %v ", savedNode)
	return node, nil
}

func (k *kubeClient) GetEndpoints(namespace string, selector labels.Selector) ([]*v1.Endpoints, error) {
	return k.sharedInformers.Core().V1().Endpoints().Lister().Endpoints(namespace).List(selector)
}
func (k *kubeClient) GetServices(namespace string, selector labels.Selector) ([]*v1.Service, error) {
	return k.sharedInformers.Core().V1().Services().Lister().Services(namespace).List(selector)
}

func (k *kubeClient) GetNodes() ([]*v1.Node, error) {
	nodes, err := k.sharedInformers.Core().V1().Nodes().Lister().List(labels.Everything())
	if err != nil {
		return nil, err
	}
	if len(nodes) == 0 {
		list, err := k.kubeclient.Nodes().List(metav1.ListOptions{})
		if err != nil {
			return nil, err
		}
		for _, node := range list.Items {
			nodes = append(nodes, &node)
		}
	}
	return nodes, nil
}

func (k *kubeClient) GetNode(nodeName string) (*v1.Node, error) {
	return k.sharedInformers.Core().V1().Nodes().Lister().Get(nodeName)
}