From 4c34b9efcd539c819648c927d7e3f53220df8ad2 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Wed, 25 Feb 2026 22:58:40 +0200
Subject: Fix stream paused scrolling and apply pending TUI/probe updates

---
 internal/statsengine/engine.go            | 29 +++++++++++++++++++++++++++++
 internal/statsengine/engine_reset_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 internal/statsengine/engine_reset_test.go

(limited to 'internal/statsengine')

diff --git a/internal/statsengine/engine.go b/internal/statsengine/engine.go
index fd46cc3..1ef58cf 100644
--- a/internal/statsengine/engine.go
+++ b/internal/statsengine/engine.go
@@ -16,6 +16,7 @@ type Engine struct {
 
 	now       func() time.Time
 	startedAt time.Time
+	topN      int
 
 	totalSyscalls   uint64
 	totalErrors     uint64
@@ -72,6 +73,7 @@ func newEngineWithClock(topN int, now func() time.Time) *Engine {
 	return &Engine{
 		now:              now,
 		startedAt:        now(),
+		topN:             topN,
 		syscalls:         newSyscallAccumulator(),
 		files:            newFileRankerWithConfig(topN),
 		processes:        newProcessAccumulatorWithConfig(topN),
@@ -83,6 +85,33 @@ func newEngineWithClock(topN int, now func() time.Time) *Engine {
 	}
 }
 
+// Reset clears all accumulated stats and restarts series baselines.
+func (e *Engine) Reset() {
+	if e == nil {
+		return
+	}
+
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	e.startedAt = e.now()
+	e.totalSyscalls = 0
+	e.totalErrors = 0
+	e.totalBytes = 0
+	e.totalReadBytes = 0
+	e.totalWriteBytes = 0
+	e.totalLatency = 0
+	e.totalGap = 0
+	e.syscalls = newSyscallAccumulator()
+	e.files = newFileRankerWithConfig(e.topN)
+	e.processes = newProcessAccumulatorWithConfig(e.topN)
+	e.latencyHist = newHistogram()
+	e.gapHist = newHistogram()
+	e.latencySeries = newRingTimeSeries()
+	e.gapSeries = newRingTimeSeries()
+	e.throughputSeries = newRingTimeSeries()
+}
+
 // Ingest updates all aggregates for one event pair.
 func (e *Engine) Ingest(pair *event.Pair) {
 	if e == nil || pair == nil {
diff --git a/internal/statsengine/engine_reset_test.go b/internal/statsengine/engine_reset_test.go
new file mode 100644
index 0000000..7a86c86
--- /dev/null
+++ b/internal/statsengine/engine_reset_test.go
@@ -0,0 +1,27 @@
+package statsengine
+
+import (
+	"testing"
+	"time"
+
+	"ior/internal/types"
+)
+
+func TestEngineResetClearsAccumulatedStats(t *testing.T) {
+	e := NewEngine(8)
+	e.Ingest(newEnginePair(types.SYS_ENTER_READ, 7, types.READ_CLASSIFIED, "test", 1, "/tmp/a", 7, 1000, 50))
+	before := e.Snapshot()
+	if before.TotalSyscalls == 0 {
+		t.Fatalf("expected non-zero totals before reset")
+	}
+
+	time.Sleep(1 * time.Millisecond)
+	e.Reset()
+	after := e.Snapshot()
+	if after.TotalSyscalls != 0 || after.TotalBytes != 0 || after.TotalErrors != 0 {
+		t.Fatalf("expected totals cleared after reset, got %+v", after)
+	}
+	if after.Elapsed > 2*time.Second {
+		t.Fatalf("expected elapsed to restart near zero, got %s", after.Elapsed)
+	}
+}
-- 
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