// hasSomeLifeLeft returns true if the lease has at least a minimum of
// lifetime left until expiration, and thus can be used.
func (s *LeaseState) hasSomeLifeLeft(clock *hlc.Clock) bool {
	if s.testingKnobs.CanUseExpiredLeases {
		return true
	}
	minDesiredExpiration := clock.Now().GoTime().Add(MinLeaseDuration)
	return s.expiration.After(minDesiredExpiration)
}

// processReplica processes a single replica. This should not be
// called externally to the queue. bq.mu.Lock must not be held
// while calling this method.
func (bq *baseQueue) processReplica(
	queueCtx context.Context, repl *Replica, clock *hlc.Clock,
) error {
	bq.processMu.Lock()
	defer bq.processMu.Unlock()

	// Load the system config.
	cfg, ok := bq.gossip.GetSystemConfig()
	if !ok {
		log.VEventf(queueCtx, 1, "no system config available, skipping")
		return nil
	}

	if bq.requiresSplit(cfg, repl) {
		// Range needs to be split due to zone configs, but queue does
		// not accept unsplit ranges.
		log.VEventf(queueCtx, 3, "split needed; skipping")
		return nil
	}

	// Putting a span in a context means that events will no longer go to the
	// event log. Use queueCtx for events that are intended for the event log.
	ctx, span := bq.AnnotateCtxWithSpan(queueCtx, bq.name)
	defer span.Finish()
	// Also add the Replica annotations to ctx.
	ctx = repl.AnnotateCtx(ctx)
	ctx, cancel := context.WithTimeout(ctx, bq.processTimeout)
	defer cancel()
	log.Eventf(ctx, "processing replica")

	if err := repl.IsDestroyed(); err != nil {
		log.VEventf(queueCtx, 3, "replica destroyed (%s); skipping", err)
		return nil
	}

	// If the queue requires a replica to have the range lease in
	// order to be processed, check whether this replica has range lease
	// and renew or acquire if necessary.
	if bq.needsLease {
		// Create a "fake" get request in order to invoke redirectOnOrAcquireLease.
		if err := repl.redirectOnOrAcquireLease(ctx); err != nil {
			switch v := err.GetDetail().(type) {
			case *roachpb.NotLeaseHolderError, *roachpb.RangeNotFoundError:
				log.VEventf(queueCtx, 3, "%s; skipping", v)
				return nil
			default:
				return errors.Wrapf(err.GoError(), "%s: could not obtain lease", repl)
			}
		}
		log.Event(ctx, "got range lease")
	}

	log.VEventf(queueCtx, 3, "processing")
	if err := bq.impl.process(ctx, clock.Now(), repl, cfg); err != nil {
		return err
	}
	log.Event(ctx, "done")
	bq.successes.Inc(1)
	return nil
}

// waitAndProcess waits for the pace interval and processes the replica
// if repl is not nil. The method returns true when the scanner needs
// to be stopped. The method also removes a replica from queues when it
// is signaled via the removed channel.
func (rs *replicaScanner) waitAndProcess(
	ctx context.Context, start time.Time, clock *hlc.Clock, stopper *stop.Stopper, repl *Replica,
) bool {
	waitInterval := rs.paceInterval(start, timeutil.Now())
	rs.waitTimer.Reset(waitInterval)
	if log.V(6) {
		log.Infof(ctx, "wait timer interval set to %s", waitInterval)
	}
	for {
		select {
		case <-rs.waitTimer.C:
			if log.V(6) {
				log.Infof(ctx, "wait timer fired")
			}
			rs.waitTimer.Read = true
			if repl == nil {
				return false
			}

			if log.V(2) {
				log.Infof(ctx, "replica scanner processing %s", repl)
			}
			for _, q := range rs.queues {
				q.MaybeAdd(repl, clock.Now())
			}
			return false

		case repl := <-rs.removed:
			rs.removeReplica(repl)

		case <-stopper.ShouldStop():
			return true
		}
	}
}

// newTimestampCache returns a new timestamp cache with supplied
// hybrid clock.
func newTimestampCache(clock *hlc.Clock) *timestampCache {
	tc := &timestampCache{
		rCache:                cache.NewIntervalCache(cache.Config{Policy: cache.CacheFIFO}),
		wCache:                cache.NewIntervalCache(cache.Config{Policy: cache.CacheFIFO}),
		evictionSizeThreshold: defaultEvictionSizeThreshold,
	}
	tc.Clear(clock.Now())
	tc.rCache.Config.ShouldEvict = tc.shouldEvict
	tc.wCache.Config.ShouldEvict = tc.shouldEvict
	return tc
}

func (m *LeaseManager) ExpireLeases(clock *hlc.Clock) {
	past := clock.Now().GoTime().Add(-time.Millisecond)

	m.tableNames.mu.Lock()
	for _, lease := range m.tableNames.tables {
		lease.expiration = parser.DTimestamp{
			Time: past,
		}
	}
	m.tableNames.mu.Unlock()
}

// MakeRuntimeStatSampler constructs a new RuntimeStatSampler object.
func MakeRuntimeStatSampler(clock *hlc.Clock) RuntimeStatSampler {
	// Construct the build info metric. It is constant.
	// We first build set the labels on the metadata.
	info := build.GetInfo()
	timestamp, err := info.Timestamp()
	if err != nil {
		// We can't panic here, tests don't have a build timestamp.
		log.Warningf(context.TODO(), "Could not parse build timestamp: %v", err)
	}

	metaBuildTimestamp.AddLabel("tag", info.Tag)
	metaBuildTimestamp.AddLabel("go_version", info.GoVersion)

	buildTimestamp := metric.NewGauge(metaBuildTimestamp)
	buildTimestamp.Update(timestamp)

	return RuntimeStatSampler{
		clock:          clock,
		startTimeNanos: clock.PhysicalNow(),
		CgoCalls:       metric.NewGauge(metaCgoCalls),
		Goroutines:     metric.NewGauge(metaGoroutines),
		GoAllocBytes:   metric.NewGauge(metaGoAllocBytes),
		GoTotalBytes:   metric.NewGauge(metaGoTotalBytes),
		CgoAllocBytes:  metric.NewGauge(metaCgoAllocBytes),
		CgoTotalBytes:  metric.NewGauge(metaCgoTotalBytes),
		GcCount:        metric.NewGauge(metaGCCount),
		GcPauseNS:      metric.NewGauge(metaGCPauseNS),
		GcPausePercent: metric.NewGaugeFloat64(metaGCPausePercent),
		CPUUserNS:      metric.NewGauge(metaCPUUserNS),
		CPUUserPercent: metric.NewGaugeFloat64(metaCPUUserPercent),
		CPUSysNS:       metric.NewGauge(metaCPUSysNS),
		CPUSysPercent:  metric.NewGaugeFloat64(metaCPUSysPercent),
		Rss:            metric.NewGauge(metaRSS),
		FDOpen:         metric.NewGauge(metaFDOpen),
		FDSoftLimit:    metric.NewGauge(metaFDSoftLimit),
		Uptime:         metric.NewGauge(metaUptime),
		BuildTimestamp: buildTimestamp,
	}
}

// LeaseExpiration returns an int64 to increment a manual clock with to
// make sure that all active range leases expire.
func (s *Store) LeaseExpiration(clock *hlc.Clock) int64 {
	// Due to lease extensions, the remaining interval can be longer than just
	// the sum of the offset (=length of stasis period) and the active
	// duration, but definitely not by 2x.
	return 2 * int64(s.cfg.RangeLeaseActiveDuration+clock.MaxOffset())
}

func (l *Liveness) isLive(clock *hlc.Clock) bool {
	expiration := l.Expiration.Add(-int64(clock.MaxOffset()), 0)
	return clock.Now().Less(expiration)
}

// hasSomeLifeLeft returns true if the lease has at least a minimum of lifetime
// left until expiration, and thus can be used.
func (s *LeaseState) hasSomeLifeLeft(clock *hlc.Clock) bool {
	minDesiredExpiration := clock.Now().GoTime().Add(MinLeaseDuration)
	return s.expiration.After(minDesiredExpiration)
}