package balance

import (
	"hpds_control_center/model"
)

// WeightRoundRobinBalance 加权轮询负载
type WeightRoundRobinBalance struct {
	curIndex int
	rss      []*WeightNode
	rsw      []int
}

type WeightNode struct {
	node            model.NodeLastStateItem
	Weight          int //初始化时对节点约定的权重
	currentWeight   int //节点临时权重，每轮都会变化
	effectiveWeight int //有效权重, 默认与weight相同 , totalWeight = sum(effectiveWeight)  //出现故障就-1
}

//1, currentWeight = currentWeight + effectiveWeight
//2, 选中最大的currentWeight节点为选中节点
//3, currentWeight = currentWeight - totalWeight

func (r *WeightRoundRobinBalance) Add(params model.NodeLastStateItem) error {
	weightCpu := params.CpuUsed
	weightMem := float64(params.MemUsed*100) / float64(params.MemUsed)
	weightSwap := float64(params.SwapTotal*100) / float64(params.SwapTotal)
	weightTask := 0.0
	if len(params.ExecTask) > 0 {
		weightTask = 0
	} else {
		weightTask = 100
	}
	node := &WeightNode{
		node:   params,
		Weight: int(400 - weightCpu - weightMem - weightSwap - weightTask),
	}
	node.effectiveWeight = node.Weight
	r.rss = append(r.rss, node)
	return nil
}

func (r *WeightRoundRobinBalance) Next() int64 {
	var best *WeightNode
	total := 0
	for i := 0; i < len(r.rss); i++ {
		w := r.rss[i]
		//1 计算所有有效权重
		total += w.effectiveWeight
		//2 修改当前节点临时权重
		w.currentWeight += w.effectiveWeight
		//3 有效权重默认与权重相同，通讯异常时-1, 通讯成功+1，直到恢复到weight大小
		if w.effectiveWeight < w.Weight {
			w.effectiveWeight++
		}

		//4 选中最大临时权重节点
		if best == nil || w.currentWeight > best.currentWeight {
			best = w
		}
	}

	if best == nil {
		return 0
	}
	//5 变更临时权重为 临时权重-有效权重之和
	best.currentWeight -= total
	return best.node.NodeId
}

func (r *WeightRoundRobinBalance) Get(int64) (int64, error) {
	return r.Next(), nil
}

func (r *WeightRoundRobinBalance) Update() {

}