eta.go

// Copyright (C) 2019-2023, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.

package timer

import (
	"encoding/binary"
	"time"
)

// ProgressFromHash returns the progress out of MaxUint64 assuming [b] is a key
// in a uniformly distributed sequence that is being iterated lexicographically.
func ProgressFromHash(b []byte) uint64 {
	// binary.BigEndian.Uint64 will panic if the input length is less than 8, so
	// pad 0s as needed.
	var progress [8]byte
	copy(progress[:], b)
	return binary.BigEndian.Uint64(progress[:])
}

// EstimateETA attempts to estimate the remaining time for a job to finish given
// the [startTime] and it's current progress.
func EstimateETA(startTime time.Time, progress, end uint64) time.Duration {
	timeSpent := time.Since(startTime)

	percentExecuted := float64(progress) / float64(end)
	estimatedTotalDuration := time.Duration(float64(timeSpent) / percentExecuted)
	eta := estimatedTotalDuration - timeSpent
	return eta.Round(time.Second)
}