add wrappers/count

store.go

@@ -24,3 +24,7 @@ type Store interface {
 	// SaveEvent is called once Relay.AcceptEvent reports true.
 	SaveEvent(context.Context, *nostr.Event) error
 }
+
+type Counter interface {
+	CountEvents(context.Context, nostr.Filter) (int64, error)
+}

wrappers/count/count.go

@@ -0,0 +1,34 @@
+package count
+
+import (
+	"context"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+type Wrapper struct {
+	eventstore.Store
+}
+
+var _ eventstore.Store = (*Wrapper)(nil)
+
+func (w Wrapper) CountEvents(ctx context.Context, filter nostr.Filter) (int64, error) {
+	if counter, ok := w.Store.(eventstore.Counter); ok {
+		return counter.CountEvents(ctx, filter)
+	}
+
+	ch, err := w.Store.QueryEvents(ctx, filter)
+	if err != nil {
+		return 0, err
+	}
+	if ch == nil {
+		return 0, nil
+	}
+
+	var count int64
+	for range ch {
+		count++
+	}
+	return count, nil
+}