chore(das): clean up daser recency check

das/daser.go

@@ -150,7 +150,7 @@ func (d *DASer) Stop(ctx context.Context) error {
 func (d *DASer) sample(ctx context.Context, h *header.ExtendedHeader) error {
 	// short-circuit if pruning is enabled and the header is outside the
 	// availability window
-	if !d.isWithinSamplingWindow(h) {
+	if !pruner.IsWithinAvailabilityWindow(h.Time(), pruner.AvailabilityWindow(d.params.SamplingWindow)) {
 		log.Debugw("skipping header outside sampling window", "height", h.Height(),
 			"time", h.Time())
 		return nil
@@ -171,14 +171,6 @@ func (d *DASer) sample(ctx context.Context, h *header.ExtendedHeader) error {
 	return nil
 }
 
-func (d *DASer) isWithinSamplingWindow(eh *header.ExtendedHeader) bool {
-	// if sampling window is not set, then all headers are within the window
-	if d.params.SamplingWindow == 0 {
-		return true
-	}
-	return pruner.IsWithinAvailabilityWindow(eh.Time(), pruner.AvailabilityWindow(d.params.SamplingWindow))
-}
-
 // SamplingStats returns the current statistics over the DA sampling process.
 func (d *DASer) SamplingStats(ctx context.Context) (SamplingStats, error) {
 	return d.sampler.stats(ctx)

das/daser_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/celestiaorg/celestia-node/header"
 	"github.com/celestiaorg/celestia-node/header/headertest"
 	headerfraud "github.com/celestiaorg/celestia-node/header/headertest/fraud"
+	"github.com/celestiaorg/celestia-node/pruner"
 	"github.com/celestiaorg/celestia-node/share"
 	"github.com/celestiaorg/celestia-node/share/availability/full"
 	"github.com/celestiaorg/celestia-node/share/availability/light"
@@ -275,7 +276,11 @@ func TestDASer_SamplingWindow(t *testing.T) {
 			eh := headertest.RandExtendedHeader(t)
 			eh.RawHeader.Time = tt.timestamp
 
-			assert.Equal(t, tt.withinWindow, daser.isWithinSamplingWindow(eh))
+			assert.Equal(
+				t,
+				tt.withinWindow,
+				pruner.IsWithinAvailabilityWindow(eh.Time(), pruner.AvailabilityWindow(daser.params.SamplingWindow)),
+			)
 		})
 	}
 

pruner/window.go

@@ -7,5 +7,8 @@ import (
 type AvailabilityWindow time.Duration
 
 func IsWithinAvailabilityWindow(t time.Time, window AvailabilityWindow) bool {
+	if window == AvailabilityWindow(time.Duration(0)) {
+		return true
+	}
 	return time.Since(t) <= time.Duration(window)
 }