package s3lifecycle

import "time"

// ComputeDueAt returns the earliest wall-clock time the (rule, kind) action
// can fire for info. Returns zero time when no action can fire for this
// entry. Used by reader/bootstrap to decide pending vs. inline-delete.
func ComputeDueAt(rule *Rule, kind ActionKind, info *ObjectInfo) time.Time {
	if rule == nil || info == nil || rule.Status != StatusEnabled {
		return time.Time{}
	}
	if !filterMatches(rule, info) {
		return time.Time{}
	}

	switch kind {
	case ActionKindAbortMPU:
		if info.IsMPUInit && rule.AbortMPUDaysAfterInitiation > 0 {
			return info.ModTime.AddDate(0, 0, rule.AbortMPUDaysAfterInitiation)
		}
	case ActionKindExpiredDeleteMarker:
		if info.IsLatest && info.IsDeleteMarker && rule.ExpiredObjectDeleteMarker && info.NumVersions == 1 {
			return info.ModTime
		}
	case ActionKindExpirationDays:
		if info.IsLatest && !info.IsDeleteMarker && rule.ExpirationDays > 0 {
			return info.ModTime.AddDate(0, 0, rule.ExpirationDays)
		}
	case ActionKindExpirationDate:
		if info.IsLatest && !info.IsDeleteMarker && !rule.ExpirationDate.IsZero() {
			return rule.ExpirationDate
		}
	case ActionKindNoncurrentDays:
		if !info.IsLatest && rule.NoncurrentVersionExpirationDays > 0 {
			base := info.SuccessorModTime
			if base.IsZero() {
				base = info.ModTime
			}
			return base.AddDate(0, 0, rule.NoncurrentVersionExpirationDays)
		}
	case ActionKindNewerNoncurrent:
		if !info.IsLatest && rule.NoncurrentVersionExpirationDays == 0 && rule.NewerNoncurrentVersions > 0 {
			if !info.SuccessorModTime.IsZero() {
				return info.SuccessorModTime
			}
			return info.ModTime
		}
	}
	return time.Time{}
}