/*
Copyright 2016 The Kubernetes 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 priorities

import (
	"fmt"

	"k8s.io/api/core/v1"
	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"

	"github.com/golang/glog"
)

// CountIntolerableTaintsPreferNoSchedule gives the count of intolerable taints of a pod with effect PreferNoSchedule
func countIntolerableTaintsPreferNoSchedule(taints []v1.Taint, tolerations []v1.Toleration) (intolerableTaints int) {
	for _, taint := range taints {
		// check only on taints that have effect PreferNoSchedule
		if taint.Effect != v1.TaintEffectPreferNoSchedule {
			continue
		}

		if !v1helper.TolerationsTolerateTaint(tolerations, &taint) {
			intolerableTaints++
		}
	}
	return
}

// getAllTolerationEffectPreferNoSchedule gets the list of all Tolerations with Effect PreferNoSchedule or with no effect.
func getAllTolerationPreferNoSchedule(tolerations []v1.Toleration) (tolerationList []v1.Toleration) {
	for _, toleration := range tolerations {
		// Empty effect means all effects which includes PreferNoSchedule, so we need to collect it as well.
		if len(toleration.Effect) == 0 || toleration.Effect == v1.TaintEffectPreferNoSchedule {
			tolerationList = append(tolerationList, toleration)
		}
	}
	return
}

// ComputeTaintTolerationPriorityMap prepares the priority list for all the nodes based on the number of intolerable taints on the node
func ComputeTaintTolerationPriorityMap(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (schedulerapi.HostPriority, error) {
	node := nodeInfo.Node()
	if node == nil {
		return schedulerapi.HostPriority{}, fmt.Errorf("node not found")
	}
	// To hold all the tolerations with Effect PreferNoSchedule
	var tolerationsPreferNoSchedule []v1.Toleration
	if priorityMeta, ok := meta.(*priorityMetadata); ok {
		tolerationsPreferNoSchedule = priorityMeta.podTolerations

	} else {
		tolerationsPreferNoSchedule = getAllTolerationPreferNoSchedule(pod.Spec.Tolerations)
	}

	return schedulerapi.HostPriority{
		Host:  node.Name,
		Score: countIntolerableTaintsPreferNoSchedule(node.Spec.Taints, tolerationsPreferNoSchedule),
	}, nil
}

// ComputeTaintTolerationPriorityReduce calculates the source of each node based on the number of intolerable taints on the node
func ComputeTaintTolerationPriorityReduce(pod *v1.Pod, meta interface{}, nodeNameToInfo map[string]*schedulercache.NodeInfo, result schedulerapi.HostPriorityList) error {
	var maxCount int
	for i := range result {
		if result[i].Score > maxCount {
			maxCount = result[i].Score
		}
	}
	maxCountFloat := float64(maxCount)

	for i := range result {
		fScore := float64(schedulerapi.MaxPriority)
		if maxCountFloat > 0 {
			fScore = (1.0 - float64(result[i].Score)/maxCountFloat) * float64(schedulerapi.MaxPriority)
		}
		if glog.V(10) {
			// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
			// not logged. There is visible performance gain from it.
			glog.Infof("%v -> %v: Taint Toleration Priority, Score: (%d)", pod.Name, result[i].Host, int(fScore))
		}
		result[i].Score = int(fScore)
	}
	return nil
}