package sectorstorage

import "container/heap"

type requestQueue []*workerRequest

func (q requestQueue) Len() int { return len(q) }

func (q requestQueue) Less(i, j int) bool {
	return q[i].taskType.Less(q[j].taskType)
}

func (q requestQueue) Swap(i, j int) {
	q[i], q[j] = q[j], q[i]
	q[i].index = i
	q[j].index = j
}

func (q *requestQueue) Push(x interface{}) {
	n := len(*q)
	item := x.(*workerRequest)
	item.index = n
	*q = append(*q, item)
}

func (q *requestQueue) Pop() interface{} {
	old := *q
	n := len(old)
	item := old[n-1]
	old[n-1] = nil  // avoid memory leak
	item.index = -1 // for safety
	*q = old[0 : n-1]
	return item
}

var _ heap.Interface = &requestQueue{}