package sealer

import (
	"math"

	"github.com/filecoin-project/lotus/storage/sealer/storiface"
)

func NewSpreadAssigner() Assigner {
	return &AssignerCommon{
		WindowSel: SpreadWS,
	}
}

func SpreadWS(sh *Scheduler, queueLen int, acceptableWindows [][]int, windows []SchedWindow) int {
	scheduled := 0
	rmQueue := make([]int, 0, queueLen)
	workerAssigned := map[storiface.WorkerID]int{}

	for sqi := 0; sqi < queueLen; sqi++ {
		task := (*sh.SchedQueue)[sqi]

		selectedWindow := -1
		var needRes storiface.Resources
		var info storiface.WorkerInfo
		var bestWid storiface.WorkerID
		bestAssigned := math.MaxInt // smaller = better

		for i, wnd := range acceptableWindows[task.IndexHeap] {
			wid := sh.OpenWindows[wnd].Worker
			w := sh.Workers[wid]

			res := w.Info.Resources.ResourceSpec(task.Sector.ProofType, task.TaskType)

			log.Debugf("SCHED try assign sqi:%d sector %d to window %d (awi:%d)", sqi, task.Sector.ID.Number, wnd, i)

			if !windows[wnd].Allocated.CanHandleRequest(task.SealTask(), res, wid, "schedAssign", w.Info) {
				continue
			}

			wu, _ := workerAssigned[wid]
			if wu >= bestAssigned {
				continue
			}

			info = w.Info
			needRes = res
			bestWid = wid
			selectedWindow = wnd
			bestAssigned = wu
		}

		if selectedWindow < 0 {
			// all windows full
			continue
		}

		log.Debugw("SCHED ASSIGNED",
			"sqi", sqi,
			"sector", task.Sector.ID.Number,
			"task", task.TaskType,
			"window", selectedWindow,
			"worker", bestWid,
			"assigned", bestAssigned)

		workerAssigned[bestWid]++
		windows[selectedWindow].Allocated.Add(task.SealTask(), info.Resources, needRes)
		windows[selectedWindow].Todo = append(windows[selectedWindow].Todo, task)

		rmQueue = append(rmQueue, sqi)
		scheduled++
	}

	if len(rmQueue) > 0 {
		for i := len(rmQueue) - 1; i >= 0; i-- {
			sh.SchedQueue.Remove(rmQueue[i])
		}
	}

	return scheduled
}