package node

import (
	"fmt"
	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/client-go/informers"
	resourceheper "k8s.io/kubectl/pkg/util/resource"
	"kubesphere.io/kubesphere/pkg/api"
	clusterv1alpha1 "kubesphere.io/kubesphere/pkg/apis/cluster/v1alpha1"
	"kubesphere.io/kubesphere/pkg/apiserver/query"
	"kubesphere.io/kubesphere/pkg/models/resources/v1alpha3"
)

// Those annotations were added to node only for display purposes
const (
	nodeCPURequests            = "node.kubesphere.io/cpu-requests"
	nodeMemoryRequests         = "node.kubesphere.io/memory-requests"
	nodeCPULimits              = "node.kubesphere.io/cpu-limits"
	nodeMemoryLimits           = "node.kubesphere.io/memory-limits"
	nodeCPURequestsFraction    = "node.kubesphere.io/cpu-requests-fraction"
	nodeCPULimitsFraction      = "node.kubesphere.io/cpu-limits-fraction"
	nodeMemoryRequestsFraction = "node.kubesphere.io/memory-requests-fraction"
	nodeMemoryLimitsFraction   = "node.kubesphere.io/memory-limits-fraction"
)

type nodesGetter struct {
	informers informers.SharedInformerFactory
}

func New(informers informers.SharedInformerFactory) v1alpha3.Interface {
	return &nodesGetter{
		informers: informers,
	}
}

func (c nodesGetter) Get(_, name string) (runtime.Object, error) {
	node, err := c.informers.Core().V1().Nodes().Lister().Get(name)
	if err != nil {
		return nil, err
	}

	// ignore the error, skip annotating process if error happened
	pods, _ := c.informers.Core().V1().Pods().Lister().Pods("").List(labels.Everything())
	c.annotateNode(node, pods)

	return node, nil
}

func (c nodesGetter) List(_ string, query *query.Query) (*api.ListResult, error) {
	nodes, err := c.informers.Core().V1().Nodes().Lister().List(query.Selector())
	if err != nil {
		return nil, err
	}

	// ignore the error, skip annotating process if error happened
	pods, _ := c.informers.Core().V1().Pods().Lister().Pods("").List(labels.Everything())
	var nonTerminatedPodsList []*v1.Pod
	for _, pod := range pods {
		if pod.Status.Phase != v1.PodSucceeded && pod.Status.Phase != v1.PodFailed {
			nonTerminatedPodsList = append(nonTerminatedPodsList, pod)
		}
	}

	var result []runtime.Object
	for _, node := range nodes {
		c.annotateNode(node, nonTerminatedPodsList)
		result = append(result, node)
	}

	return v1alpha3.DefaultList(result, query, c.compare, c.filter), nil
}

func (c nodesGetter) compare(left runtime.Object, right runtime.Object, field query.Field) bool {
	leftNode, ok := left.(*v1.Node)
	if !ok {
		return false
	}

	rightNode, ok := right.(*v1.Node)
	if !ok {
		return false
	}

	return v1alpha3.DefaultObjectMetaCompare(leftNode.ObjectMeta, rightNode.ObjectMeta, field)
}

func (c nodesGetter) filter(object runtime.Object, filter query.Filter) bool {
	cluster, ok := object.(*clusterv1alpha1.Cluster)
	if !ok {
		return false
	}

	return v1alpha3.DefaultObjectMetaFilter(cluster.ObjectMeta, filter)
}

// annotateNode adds cpu/memory requests usage data to node's annotations
func (c nodesGetter) annotateNode(node *v1.Node, pods []*v1.Pod) {
	if len(pods) == 0 {
		return
	}

	var nodePods []*v1.Pod
	for _, pod := range pods {
		if pod.Spec.NodeName == node.Name {
			nodePods = append(nodePods, pod)
		}
	}

	reqs, limits := c.getPodsTotalRequestAndLimits(nodePods)

	if node.Annotations == nil {
		node.Annotations = make(map[string]string)
	}

	cpuReqs, cpuLimits, memoryReqs, memoryLimits := reqs[v1.ResourceCPU], limits[v1.ResourceCPU], reqs[v1.ResourceMemory], limits[v1.ResourceMemory]
	node.Annotations[nodeCPURequests] = cpuReqs.String()
	node.Annotations[nodeCPULimits] = cpuLimits.String()
	node.Annotations[nodeMemoryRequests] = memoryReqs.String()
	node.Annotations[nodeMemoryLimits] = memoryLimits.String()

	fractionCpuReqs, fractionCpuLimits := float64(0), float64(0)
	allocatable := node.Status.Allocatable
	if allocatable.Cpu().MilliValue() != 0 {
		fractionCpuReqs = float64(cpuReqs.MilliValue()) / float64(allocatable.Cpu().MilliValue()) * 100
		fractionCpuLimits = float64(cpuLimits.MilliValue()) / float64(allocatable.Cpu().MilliValue()) * 100
	}
	fractionMemoryReqs, fractionMemoryLimits := float64(0), float64(0)
	if allocatable.Memory().Value() != 0 {
		fractionMemoryReqs = float64(memoryReqs.Value()) / float64(allocatable.Memory().Value()) * 100
		fractionMemoryLimits = float64(memoryLimits.Value()) / float64(allocatable.Memory().Value()) * 100
	}

	node.Annotations[nodeCPURequestsFraction] = fmt.Sprintf("%d%%", int(fractionCpuReqs))
	node.Annotations[nodeCPULimitsFraction] = fmt.Sprintf("%d%%", int(fractionCpuLimits))
	node.Annotations[nodeMemoryRequestsFraction] = fmt.Sprintf("%d%%", int(fractionMemoryReqs))
	node.Annotations[nodeMemoryLimitsFraction] = fmt.Sprintf("%d%%", int(fractionMemoryLimits))
}

func (c nodesGetter) getPodsTotalRequestAndLimits(pods []*v1.Pod) (reqs map[v1.ResourceName]resource.Quantity, limits map[v1.ResourceName]resource.Quantity) {
	reqs, limits = map[v1.ResourceName]resource.Quantity{}, map[v1.ResourceName]resource.Quantity{}
	for _, pod := range pods {
		podReqs, podLimits := resourceheper.PodRequestsAndLimits(pod)
		for podReqName, podReqValue := range podReqs {
			if value, ok := reqs[podReqName]; !ok {
				reqs[podReqName] = podReqValue.DeepCopy()
			} else {
				value.Add(podReqValue)
				reqs[podReqName] = value
			}
		}
		for podLimitName, podLimitValue := range podLimits {
			if value, ok := limits[podLimitName]; !ok {
				limits[podLimitName] = podLimitValue.DeepCopy()
			} else {
				value.Add(podLimitValue)
				limits[podLimitName] = value
			}
		}
	}
	return
}