package scrobble

import (
	"time"
)

// backoffSchedule maps the failure count (1-indexed: 1 = first failure
// just happened) to the delay before the next attempt. Per spec §M4a:
// 1m → 5m → 30m → 2h → 6h, then give up.
var backoffSchedule = []time.Duration{
	1 * time.Minute,
	5 * time.Minute,
	30 * time.Minute,
	2 * time.Hour,
	6 * time.Hour,
}

const maxAttempts = 5

// backoffDelay returns the delay before the next attempt given the value
// of the `attempts` column AFTER the failure has been recorded (1-indexed:
// attempts=1 means the first failure just happened, the next retry should
// wait 1 minute). Returns (_, false) when attempts > maxAttempts (the
// caller should mark the row failed).
func backoffDelay(attempts int) (time.Duration, bool) {
	if attempts < 1 || attempts > maxAttempts {
		return 0, false
	}
	return backoffSchedule[attempts-1], true
}