16 files changed, 4515 insertions, 0 deletions

diff --git a/internal/tui/flamegraph/animation.go b/internal/tui/flamegraph/animation.go
new file mode 100644
index 0000000..103d43b
--- /dev/null
+++ b/internal/tui/flamegraph/animation.go
@@ -0,0 +1,145 @@
+package flamegraph
+
+import (
+	"math"
+
+	"github.com/charmbracelet/harmonica"
+)
+
+const springEpsilon = 0.01
+
+type frameSpring struct {
+	path        string
+	base        tuiFrame
+	widthSpring harmonica.Spring
+	colSpring   harmonica.Spring
+
+	currentW    float64
+	currentCol  float64
+	velocityW   float64
+	velocityCol float64
+
+	targetW   float64
+	targetCol float64
+}
+
+// AnimationState stores per-frame spring interpolation state.
+type AnimationState struct {
+	springs []frameSpring
+	frames  []tuiFrame
+	settled bool
+
+	fps             int
+	angularVelocity float64
+	damping         float64
+}
+
+// NewAnimationState builds a spring animation state with the provided parameters.
+func NewAnimationState(fps int, angularVelocity, damping float64) AnimationState {
+	if fps <= 0 {
+		fps = 30
+	}
+	return AnimationState{
+		fps:             fps,
+		angularVelocity: angularVelocity,
+		damping:         damping,
+		settled:         true,
+	}
+}
+
+// SetTargets sets new frame targets, preserving spring motion for matching paths.
+func (a *AnimationState) SetTargets(targets []tuiFrame) {
+	existing := make(map[string]frameSpring, len(a.springs))
+	for _, spring := range a.springs {
+		existing[spring.path] = spring
+	}
+
+	next := make([]frameSpring, 0, len(targets))
+	for _, target := range targets {
+		spring, ok := existing[target.Path]
+		if !ok {
+			spring = frameSpring{
+				path:       target.Path,
+				currentW:   float64(target.Width),
+				currentCol: float64(target.Col),
+			}
+		}
+		spring.base = target
+		spring.targetW = float64(target.Width)
+		spring.targetCol = float64(target.Col)
+		spring.widthSpring = harmonica.NewSpring(harmonica.FPS(a.fps), a.angularVelocity, a.damping)
+		spring.colSpring = harmonica.NewSpring(harmonica.FPS(a.fps), a.angularVelocity, a.damping)
+		next = append(next, spring)
+	}
+	a.springs = next
+	if cap(a.frames) < len(a.springs) {
+		a.frames = make([]tuiFrame, len(a.springs))
+	} else {
+		a.frames = a.frames[:len(a.springs)]
+	}
+	a.settled = len(a.springs) == 0
+	for _, spring := range a.springs {
+		if !isSpringSettled(spring) {
+			a.settled = false
+			break
+		}
+	}
+}
+
+// Tick advances springs by delta seconds and returns true while animation is active.
+func (a *AnimationState) Tick(delta float64) bool {
+	if len(a.springs) == 0 {
+		a.settled = true
+		return false
+	}
+	baseDelta := harmonica.FPS(a.fps)
+	if delta <= 0 {
+		delta = baseDelta
+	}
+
+	active := false
+	for idx := range a.springs {
+		spring := &a.springs[idx]
+		if delta != baseDelta {
+			spring.widthSpring = harmonica.NewSpring(delta, a.angularVelocity, a.damping)
+			spring.colSpring = harmonica.NewSpring(delta, a.angularVelocity, a.damping)
+		}
+		spring.currentW, spring.velocityW = spring.widthSpring.Update(spring.currentW, spring.velocityW, spring.targetW)
+		spring.currentCol, spring.velocityCol = spring.colSpring.Update(spring.currentCol, spring.velocityCol, spring.targetCol)
+		if !isSpringSettled(*spring) {
+			active = true
+		}
+	}
+	a.settled = !active
+	return active
+}
+
+// CurrentFrames returns interpolated frames for the current animation step.
+func (a *AnimationState) CurrentFrames() []tuiFrame {
+	for idx, spring := range a.springs {
+		frame := spring.base
+		frame.Col = maxInt(0, int(math.Round(spring.currentCol)))
+		frame.Width = maxInt(1, int(math.Round(spring.currentW)))
+		a.frames[idx] = frame
+	}
+	return a.frames
+}
+
+// Settled reports whether all active springs are at rest.
+func (a AnimationState) Settled() bool {
+	return a.settled
+}
+
+func isSpringSettled(s frameSpring) bool {
+	return math.Abs(s.currentW-s.targetW) < springEpsilon &&
+		math.Abs(s.currentCol-s.targetCol) < springEpsilon &&
+		math.Abs(s.velocityW) < springEpsilon &&
+		math.Abs(s.velocityCol) < springEpsilon
+}
+
+func maxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
diff --git a/internal/tui/flamegraph/animation_test.go b/internal/tui/flamegraph/animation_test.go
new file mode 100644
index 0000000..94272e2
--- /dev/null
+++ b/internal/tui/flamegraph/animation_test.go
@@ -0,0 +1,50 @@
+package flamegraph
+
+import "testing"
+
+func TestAnimationStateConvergesToTarget(t *testing.T) {
+	state := NewAnimationState(30, 6.0, 1.0)
+	state.SetTargets([]tuiFrame{{Path: "root", Col: 0, Width: 10}})
+	state.SetTargets([]tuiFrame{{Path: "root", Col: 100, Width: 50}})
+
+	active := true
+	for i := 0; i < 180 && active; i++ {
+		active = state.Tick(0)
+	}
+	if active {
+		t.Fatalf("expected springs to settle within 180 ticks")
+	}
+
+	frames := state.CurrentFrames()
+	if len(frames) != 1 {
+		t.Fatalf("expected one interpolated frame, got %d", len(frames))
+	}
+	if frames[0].Col != 100 || frames[0].Width != 50 {
+		t.Fatalf("expected settled frame at col=100 width=50, got col=%d width=%d", frames[0].Col, frames[0].Width)
+	}
+	if state.Tick(0) {
+		t.Fatalf("expected settled animation to remain inactive")
+	}
+}
+
+func TestAnimationStateHandlesAddedAndRemovedFrames(t *testing.T) {
+	state := NewAnimationState(30, 6.0, 1.0)
+	state.SetTargets([]tuiFrame{
+		{Path: "root", Col: 0, Width: 20},
+		{Path: "root\x1fchild", Col: 20, Width: 20},
+	})
+	if got := len(state.CurrentFrames()); got != 2 {
+		t.Fatalf("expected 2 frames after initial targets, got %d", got)
+	}
+
+	state.SetTargets([]tuiFrame{
+		{Path: "root\x1fchild", Col: 40, Width: 30},
+	})
+	frames := state.CurrentFrames()
+	if len(frames) != 1 {
+		t.Fatalf("expected removed frame to be dropped, got %d frames", len(frames))
+	}
+	if frames[0].Path != "root\x1fchild" {
+		t.Fatalf("expected remaining frame path root\\x1fchild, got %q", frames[0].Path)
+	}
+}
diff --git a/internal/tui/flamegraph/bench_test.go b/internal/tui/flamegraph/bench_test.go
new file mode 100644
index 0000000..33d77d1
--- /dev/null
+++ b/internal/tui/flamegraph/bench_test.go
@@ -0,0 +1,401 @@
+package flamegraph
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	coreflamegraph "ior/internal/flamegraph"
+	"ior/internal/types"
+
+	"github.com/charmbracelet/harmonica"
+)
+
+var (
+	benchFramesSink []tuiFrame
+	benchStringSink string
+	benchIntSink    int
+	benchFloatSink  float64
+)
+
+func BenchmarkBuildTerminalLayout(b *testing.B) {
+	// Performance target: medium_120col should remain below 500us/op.
+	fixtures := []struct {
+		label   string
+		depth   int
+		breadth int
+	}{
+		{label: "small", depth: fixtureSmallDepth, breadth: fixtureSmallBreadth},
+		{label: "medium", depth: fixtureMediumDepth, breadth: fixtureMediumBreadth},
+		{label: "large", depth: fixtureLargeDepth, breadth: fixtureLargeBreadth},
+		{label: "deep", depth: fixtureDeepDepth, breadth: fixtureDeepBreadth},
+		{label: "wide", depth: fixtureWideDepth, breadth: fixtureWideBreadth},
+	}
+	widths := []int{80, 120, 200, 300}
+	const height = 40
+
+	snapshots := make(map[string]*snapshotNode, len(fixtures))
+	for _, fixture := range fixtures {
+		snapshots[fixture.label] = generateTestSnapshot(fixture.depth, fixture.breadth)
+	}
+
+	for _, fixture := range fixtures {
+		snapshot := snapshots[fixture.label]
+		for _, width := range widths {
+			name := fmt.Sprintf("%s_%dcol", fixture.label, width)
+			b.Run(name, func(b *testing.B) {
+				b.ReportAllocs()
+				for i := 0; i < b.N; i++ {
+					benchFramesSink = BuildTerminalLayout(snapshot, width, height)
+				}
+				if len(benchFramesSink) == 0 {
+					b.Fatal("layout returned no frames")
+				}
+			})
+		}
+	}
+}
+
+func BenchmarkRenderFrame(b *testing.B) {
+	// Performance target: medium_120x40 should remain below 2ms/op.
+	// Allocation target: run with -benchmem and keep render path below 5 allocs/op.
+	fixtures := []struct {
+		label    string
+		snapshot *snapshotNode
+	}{
+		{label: "medium", snapshot: generateTestSnapshot(fixtureMediumDepth, fixtureMediumBreadth)},
+		{label: "large", snapshot: generateTestSnapshot(fixtureLargeDepth, fixtureLargeBreadth)},
+	}
+	viewports := []struct {
+		width  int
+		height int
+	}{
+		{width: 80, height: 24},
+		{width: 120, height: 40},
+		{width: 200, height: 60},
+	}
+
+	for _, fixture := range fixtures {
+		for _, viewport := range viewports {
+			name := fmt.Sprintf("%s_%dx%d", fixture.label, viewport.width, viewport.height)
+			b.Run(name, func(b *testing.B) {
+				model := NewModel(nil)
+				model.width = viewport.width
+				model.height = viewport.height
+				model.snapshot = fixture.snapshot
+				model.rebuildFrames(false)
+				if len(model.frames) == 0 {
+					b.Fatal("render benchmark requires non-empty frame layout")
+				}
+
+				for idx := range model.frames {
+					switch idx % 12 {
+					case 0:
+						model.frames[idx].Name = "sys_enter_read"
+					case 1:
+						model.frames[idx].Name = "sys_enter_write"
+					}
+				}
+				model.selectedIdx = midDepthFrameIndex(model.frames)
+				model.subtreeSet = computeSubtreeSetInto(model.frames, model.selectedIdx, model.subtreeSet)
+				model.applySearchQuery("sys_")
+
+				b.ReportAllocs()
+				for i := 0; i < b.N; i++ {
+					benchStringSink = model.View().Content
+				}
+			})
+		}
+	}
+}
+
+func BenchmarkComputeSubtreeSet(b *testing.B) {
+	// Performance target: 1000-frame subtree membership should remain below 100us/op.
+	// Allocation target: zero allocs/op by reusing map storage.
+	cases := []struct {
+		label      string
+		frameCount int
+	}{
+		{label: "100frames", frameCount: 100},
+		{label: "1000frames", frameCount: 1000},
+		{label: "5000frames", frameCount: 5000},
+	}
+
+	for _, tc := range cases {
+		frames := benchmarkFramesForCount(tc.frameCount)
+		if len(frames) == 0 {
+			b.Fatalf("%s produced no frames", tc.label)
+		}
+		selectedIdx := midDepthFrameIndex(frames)
+		reuse := make(map[int]bool, len(frames))
+
+		b.Run(tc.label, func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				subtree := computeSubtreeSetInto(frames, selectedIdx, reuse)
+				benchIntSink = len(subtree)
+			}
+		})
+	}
+}
+
+func BenchmarkSearchHighlight(b *testing.B) {
+	// Performance target: 1000-frame search should remain below 200us/op.
+	cases := []struct {
+		label      string
+		frameCount int
+	}{
+		{label: "100frames", frameCount: 100},
+		{label: "1000frames", frameCount: 1000},
+		{label: "5000frames", frameCount: 5000},
+	}
+	queries := []string{"read", "sys_", "/srv/app"}
+
+	for _, tc := range cases {
+		frames := benchmarkFramesForCount(tc.frameCount)
+		if len(frames) == 0 {
+			b.Fatalf("%s produced no frames", tc.label)
+		}
+		decorateFramesForSearch(frames)
+
+		model := NewModel(nil)
+		model.frames = frames
+		model.selectedIdx = midDepthFrameIndex(frames)
+		model.subtreeSet = computeSubtreeSetInto(model.frames, model.selectedIdx, model.subtreeSet)
+
+		b.Run(tc.label, func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				model.applySearchQuery(queries[i%len(queries)])
+				benchIntSink = len(model.matchIndices)
+			}
+		})
+	}
+}
+
+func BenchmarkSpringUpdate(b *testing.B) {
+	// Performance target: 500 active springs should update in < 1ms per tick.
+	counts := []int{100, 500, 2000}
+	const (
+		angularVelocity = 6.0
+		damping         = 1.0
+	)
+
+	for _, count := range counts {
+		b.Run(fmt.Sprintf("%d_springs", count), func(b *testing.B) {
+			springs := make([]harmonica.Spring, count)
+			current := make([]float64, count)
+			velocity := make([]float64, count)
+			target := make([]float64, count)
+
+			for idx := range springs {
+				springs[idx] = harmonica.NewSpring(harmonica.FPS(30), angularVelocity, damping)
+				current[idx] = float64(idx)
+				target[idx] = float64(idx + 8)
+			}
+
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				for idx := range springs {
+					current[idx], velocity[idx] = springs[idx].Update(current[idx], velocity[idx], target[idx])
+				}
+				benchFloatSink = current[count-1]
+			}
+		})
+	}
+}
+
+func BenchmarkAnimationTick(b *testing.B) {
+	// Performance target: 500 animated frames should complete in < 1ms per tick.
+	// Allocation target: zero allocs/op in the tick + CurrentFrames path.
+	counts := []int{100, 500, 2000}
+
+	for _, count := range counts {
+		b.Run(fmt.Sprintf("%d_frames", count), func(b *testing.B) {
+			state := NewAnimationState(30, 6.0, 1.0)
+			base := linearFrames(count, 0, 10)
+			target := linearFrames(count, 5, 20)
+			state.SetTargets(base)
+			state.SetTargets(target)
+
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				if !state.Tick(0) {
+					for idx := range state.springs {
+						state.springs[idx].targetCol += 3
+						state.springs[idx].targetW += 2
+					}
+					state.settled = false
+				}
+				frames := state.CurrentFrames()
+				benchIntSink = frames[len(frames)-1].Width
+			}
+		})
+	}
+}
+
+func BenchmarkZoomTransition(b *testing.B) {
+	// Performance target: zoom-in transition should stay below 1ms/op.
+	snapshot := generateTestSnapshot(fixtureMediumDepth, fixtureMediumBreadth)
+	model := NewModel(nil)
+	model.width = 120
+	model.height = 40
+	model.snapshot = snapshot
+	model.rebuildFrames(false)
+	if len(model.frames) == 0 {
+		b.Fatal("zoom benchmark requires non-empty initial layout")
+	}
+	zoomPath := model.frames[midDepthFrameIndex(model.frames)].Path
+
+	b.Run("zoom_in", func(b *testing.B) {
+		benchModel := model
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			benchModel.zoomReset()
+			benchModel.selectedIdx = frameIndexByPath(benchModel.frames, zoomPath)
+			benchModel.zoomIn()
+			benchIntSink = len(benchModel.targetFrames)
+		}
+	})
+
+	b.Run("undo_zoom", func(b *testing.B) {
+		benchModel := model
+		benchModel.selectedIdx = frameIndexByPath(benchModel.frames, zoomPath)
+		benchModel.zoomIn()
+		if len(benchModel.zoomStack) == 0 {
+			b.Fatal("undo benchmark requires an active zoom stack")
+		}
+
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			benchModel.zoomUndo()
+			benchIntSink = len(benchModel.frames)
+
+			benchModel.selectedIdx = frameIndexByPath(benchModel.frames, zoomPath)
+			benchModel.zoomIn()
+		}
+	})
+}
+
+func BenchmarkLiveTrieIngestAndSnapshot(b *testing.B) {
+	// Performance target: ingest+snapshot pipeline should remain below 200us/op for small/medium cycles.
+	counts := []int{100, 1000, 10000}
+	for _, count := range counts {
+		b.Run(fmt.Sprintf("%d_events", count), func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				liveTrie := coreflamegraph.NewLiveTrie([]string{"comm", "path", "tracepoint"}, "count")
+				for eventIdx := 0; eventIdx < count; eventIdx++ {
+					traceID := types.SYS_ENTER_READ
+					if eventIdx%2 == 0 {
+						traceID = types.SYS_ENTER_WRITE
+					}
+					pair := newBenchmarkPair(
+						fmt.Sprintf("worker-%d", eventIdx%4),
+						traceID,
+						uint32(1000+(eventIdx%64)),
+						uint32(200000+eventIdx),
+						buildBenchmarkPath(8, 6, eventIdx),
+					)
+					liveTrie.Ingest(pair)
+					pair.Recycle()
+				}
+
+				payload, _ := liveTrie.SnapshotJSON()
+				var snapshot snapshotNode
+				if err := json.Unmarshal(payload, &snapshot); err != nil {
+					b.Fatalf("snapshot decode failed: %v", err)
+				}
+				benchFramesSink = BuildTerminalLayout(&snapshot, 120, 40)
+			}
+		})
+	}
+}
+
+func BenchmarkResizeRelayout(b *testing.B) {
+	// Performance target: resize relayout cost should match BuildTerminalLayout (< 500us medium@120col).
+	snapshot := generateTestSnapshot(fixtureMediumDepth, fixtureMediumBreadth)
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		frames120 := BuildTerminalLayout(snapshot, 120, 40)
+		frames80 := BuildTerminalLayout(snapshot, 80, 24)
+		benchFramesSink = BuildTerminalLayout(snapshot, 120, 40)
+		benchIntSink = len(frames120) + len(frames80) + len(benchFramesSink)
+	}
+}
+
+func benchmarkFramesForCount(frameCount int) []tuiFrame {
+	var snapshot *snapshotNode
+	switch frameCount {
+	case 100:
+		snapshot = generateTestSnapshot(fixtureDeepDepth, fixtureDeepBreadth)
+	case 1000:
+		snapshot = generateTestSnapshot(20, 5)
+	case 5000:
+		snapshot = generateTestSnapshot(fixtureWideDepth, fixtureWideBreadth)
+	default:
+		snapshot = generateTestSnapshot(10, 5)
+	}
+	return BuildTerminalLayout(snapshot, 200, 80)
+}
+
+func decorateFramesForSearch(frames []tuiFrame) {
+	for idx := range frames {
+		switch idx % 6 {
+		case 0:
+			frames[idx].Name = "sys_enter_read"
+		case 1:
+			frames[idx].Name = "sys_enter_write"
+		case 2:
+			frames[idx].Name = "read_cache_buffer"
+		case 3:
+			frames[idx].Name = "path:/srv/app/api"
+		case 4:
+			frames[idx].Name = "worker_loop"
+		default:
+			frames[idx].Name = "io_wait"
+		}
+	}
+}
+
+func midDepthFrameIndex(frames []tuiFrame) int {
+	if len(frames) == 0 {
+		return 0
+	}
+	maxDepth := 0
+	for _, frame := range frames {
+		if frame.Depth > maxDepth {
+			maxDepth = frame.Depth
+		}
+	}
+	targetDepth := maxDepth / 2
+	indices := framesAtDepth(frames, targetDepth)
+	if len(indices) == 0 {
+		return len(frames) / 2
+	}
+	return indices[len(indices)/2]
+}
+
+func frameIndexByPath(frames []tuiFrame, path string) int {
+	for idx, frame := range frames {
+		if frame.Path == path {
+			return idx
+		}
+	}
+	return 0
+}
+
+func linearFrames(count, colOffset, width int) []tuiFrame {
+	frames := make([]tuiFrame, count)
+	for idx := 0; idx < count; idx++ {
+		path := fmt.Sprintf("root%snode-%d", pathSeparator, idx)
+		frames[idx] = tuiFrame{
+			Name:  fmt.Sprintf("node-%d", idx),
+			Path:  path,
+			Col:   colOffset + idx,
+			Row:   idx % 8,
+			Width: width,
+		}
+	}
+	return frames
+}
diff --git a/internal/tui/flamegraph/controls.go b/internal/tui/flamegraph/controls.go
new file mode 100644
index 0000000..06e6d0d
--- /dev/null
+++ b/internal/tui/flamegraph/controls.go
@@ -0,0 +1,173 @@
+package flamegraph
+
+import (
+	"fmt"
+	"strings"
+
+	common "ior/internal/tui/common"
+
+	"charm.land/lipgloss/v2"
+)
+
+func (m *Model) togglePause() {
+	m.paused = !m.paused
+}
+
+func (m *Model) clearSnapshotState(clearSearch bool) {
+	m.zoomRoot = nil
+	m.zoomPath = ""
+	m.zoomStack = nil
+	m.selectedIdx = 0
+	m.snapshot = nil
+	m.globalTotal = 0
+	m.frames = nil
+	m.targetFrames = nil
+	m.matchIndices = make(map[int]bool)
+	m.filterVisible = make(map[int]bool)
+	m.subtreeSet = make(map[int]bool)
+	m.hasNavigableSnapshot = false
+	if clearSearch {
+		m.searchQuery = ""
+	}
+}
+
+func (m *Model) resetBaseline() {
+	if m.liveTrie != nil {
+		m.liveTrie.Reset()
+	}
+	m.clearSnapshotState(true)
+	m.statusMessage = "Baseline reset"
+}
+
+func (m *Model) cycleFieldOrder() {
+	if len(m.fieldPresets) == 0 {
+		return
+	}
+	m.fieldIndex = (m.fieldIndex + 1) % len(m.fieldPresets)
+	nextPreset := m.fieldPresets[m.fieldIndex]
+	if m.liveTrie != nil {
+		if err := m.liveTrie.Reconfigure(nextPreset); err != nil {
+			m.statusMessage = "Field order error: " + err.Error()
+			return
+		}
+	}
+	m.clearSnapshotState(false)
+	m.statusMessage = "Order: " + strings.Join(nextPreset, "/")
+}
+
+func (m *Model) toggleCountField() {
+	next := "bytes"
+	if m.countField == "bytes" {
+		next = "count"
+	}
+	if m.liveTrie != nil {
+		if err := m.liveTrie.SetCountField(next); err != nil {
+			m.statusMessage = "Metric toggle error: " + err.Error()
+			return
+		}
+	}
+	m.countField = next
+	m.clearSnapshotState(false)
+	m.statusMessage = "Metric: " + m.countFieldLabel() + " (new baseline)"
+}
+
+func (m *Model) toggleHelp() {
+	m.showHelp = !m.showHelp
+}
+
+func (m Model) toolbarLine() string {
+	state := lipgloss.NewStyle().Foreground(common.ColorPrimary).Render("[LIVE]")
+	if m.paused {
+		state = lipgloss.NewStyle().Foreground(common.ColorDanger).Bold(true).Render("[PAUSED]")
+	}
+	order := m.currentFieldPresetLabel()
+	line := fmt.Sprintf("%s | view:%s | o:order(%s) | b:metric(%s) | /:search | enter:zoom | u/esc:undo | r:reset | space/p:pause", state, compactFramePath(m.currentRootPath()), order, m.countFieldLabel())
+	if m.searchQuery != "" {
+		line += " | filter:" + m.searchQuery
+	}
+	if m.statusMessage != "" {
+		line += " | " + m.statusMessage
+	}
+	if m.lastKeyDebug != "" {
+		line += " | " + m.lastKeyDebug
+	}
+	width := m.width
+	if width <= 0 {
+		width = 80
+	}
+	return padOrTrim(line, width)
+}
+
+func (m Model) helpOverlay() string {
+	width := m.width
+	if width <= 0 {
+		width = 80
+	}
+	help := "Flame help: j/k depth  h/l sibling  pgup top  pgdn root  enter zoom  u/backspace/esc undo  / search  n/N matches  space/p pause  r reset baseline  o order  b metric  ? help"
+	return common.HelpBarStyle.Width(width).Render(padOrTrim(help, width))
+}
+
+func (m Model) selectionStatusLine() string {
+	width := m.width
+	if width <= 0 {
+		width = 80
+	}
+	mode := "LIVE"
+	if m.paused {
+		mode = "PAUSED"
+	}
+	if len(m.frames) == 0 {
+		line := fmt.Sprintf("[%s] sel:none | arrows/hjkl navigate | enter zoom | / filter", mode)
+		return common.HelpBarStyle.Width(width).Render(padOrTrim(line, width))
+	}
+	selIdx := m.selectedIdx
+	if selIdx < 0 || selIdx >= len(m.frames) {
+		selIdx = 0
+	}
+	frame := m.frames[selIdx]
+	systemShare := frame.Percent
+	if m.globalTotal > 0 {
+		systemShare = percentOfTotal(frame.Total, m.globalTotal)
+	}
+	metric := m.countFieldLabel()
+	shareLabel := fmt.Sprintf("%.2f%% of total %s", systemShare, metric)
+	if strings.TrimSpace(m.searchQuery) != "" && len(m.matchIndices) > 0 {
+		filterTotal, _ := filterCoverageTotals(m.frames, m.matchIndices, m.globalTotal)
+		if filterTotal > 0 {
+			selectedFilterTotal := filterCoverageTotalForPath(m.frames, m.matchIndices, frame.Path)
+			filterShare := percentOfTotal(selectedFilterTotal, filterTotal)
+			shareLabel = fmt.Sprintf("%.2f%% of filtered %s", filterShare, metric)
+		}
+	}
+	line := fmt.Sprintf("[%s] sel:%d/%d %s | path:%s | depth:%d | total(%s):%d | %s",
+		mode, selIdx+1, len(m.frames), frame.Name, compactFramePath(frame.Path), frame.Depth, m.countFieldLabel(), frame.Total, shareLabel)
+	if m.searchQuery != "" {
+		line += " | filter:" + m.searchQuery
+	}
+	return common.HelpBarStyle.Width(width).Render(padOrTrim(line, width))
+}
+
+func (m Model) currentFieldPresetLabel() string {
+	if len(m.fieldPresets) == 0 {
+		return "n/a"
+	}
+	idx := m.fieldIndex
+	if idx < 0 {
+		idx = 0
+	}
+	if idx >= len(m.fieldPresets) {
+		idx = len(m.fieldPresets) - 1
+	}
+	return strings.Join(m.fieldPresets[idx], "/")
+}
+
+func (m Model) countFieldLabel() string {
+	switch m.countField {
+	case "count":
+		return "events"
+	case "bytes":
+		return "bytes"
+	default:
+		return m.countField
+	}
+}
diff --git a/internal/tui/flamegraph/doc.go b/internal/tui/flamegraph/doc.go
new file mode 100644
index 0000000..7982ae9
--- /dev/null
+++ b/internal/tui/flamegraph/doc.go
@@ -0,0 +1,2 @@
+// Package flamegraph renders the interactive terminal flamegraph dashboard tab.
+package flamegraph
diff --git a/internal/tui/flamegraph/model.go b/internal/tui/flamegraph/model.go
new file mode 100644
index 0000000..cc208ae
--- /dev/null
+++ b/internal/tui/flamegraph/model.go
@@ -0,0 +1,1027 @@
+package flamegraph
+
+import (
+	"encoding/json"
+	"fmt"
+	"image/color"
+	"slices"
+	"sort"
+	"strings"
+	"time"
+
+	common "ior/internal/tui/common"
+
+	"charm.land/bubbles/v2/key"
+	"charm.land/bubbles/v2/textinput"
+	tea "charm.land/bubbletea/v2"
+)
+
+type snapshotNode struct {
+	Name     string          `json:"n"`
+	Value    uint64          `json:"v"`
+	Total    uint64          `json:"t"`
+	Children []*snapshotNode `json:"c,omitempty"`
+}
+
+type animTickMsg struct{}
+
+const animFrameDuration = 33 * time.Millisecond
+
+// LiveTrieSource is the minimal trie contract needed by the flamegraph TUI model.
+type LiveTrieSource interface {
+	Fields() []string
+	CountField() string
+	Reconfigure([]string) error
+	SetCountField(string) error
+	Reset()
+	Version() uint64
+	SnapshotJSON() ([]byte, uint64)
+}
+
+type zoomState struct {
+	path                string
+	previousSelectedIdx int
+}
+
+type flameKeyMap struct {
+	MoveShallower key.Binding
+	MoveDeeper    key.Binding
+	PrevSibling   key.Binding
+	NextSibling   key.Binding
+	JumpTop       key.Binding
+	JumpRoot      key.Binding
+	ZoomIn        key.Binding
+	ZoomUndo      key.Binding
+	ZoomReset     key.Binding
+}
+
+func defaultFlameKeyMap() flameKeyMap {
+	return flameKeyMap{
+		MoveShallower: key.NewBinding(key.WithKeys("j", "down")),
+		MoveDeeper:    key.NewBinding(key.WithKeys("k", "up")),
+		PrevSibling:   key.NewBinding(key.WithKeys("h", "left")),
+		NextSibling:   key.NewBinding(key.WithKeys("l", "right")),
+		JumpTop:       key.NewBinding(key.WithKeys("pgup", "pageup")),
+		JumpRoot:      key.NewBinding(key.WithKeys("pgdown", "pgdn", "pagedown")),
+		ZoomIn:        key.NewBinding(key.WithKeys("enter")),
+		ZoomUndo:      key.NewBinding(key.WithKeys("backspace", "u", "esc")),
+		ZoomReset:     key.NewBinding(),
+	}
+}
+
+// Model is the Bubble Tea model for the TUI flamegraph tab.
+type Model struct {
+	liveTrie    LiveTrieSource
+	lastVersion uint64
+	snapshot    *snapshotNode
+	globalTotal uint64
+
+	frames       []tuiFrame
+	targetFrames []tuiFrame
+	width        int
+	height       int
+
+	selectedIdx int
+	zoomStack   []zoomState
+	zoomRoot    *snapshotNode
+	zoomPath    string
+
+	searchActive  bool
+	searchInput   textinput.Model
+	searchQuery   string
+	matchIndices  map[int]bool
+	filterVisible map[int]bool
+	subtreeSet    map[int]bool
+	showHelp      bool
+	statusMessage string
+	lastKeyDebug  string
+
+	fieldPresets [][]string
+	fieldIndex   int
+	countField   string
+
+	animation AnimationState
+	animating bool
+	paused    bool
+	// hasNavigableSnapshot flips once we have at least one selectable non-root frame.
+	hasNavigableSnapshot bool
+	isDark               bool
+	keys                 flameKeyMap
+}
+
+// tuiFrame stores one terminal flamegraph frame cell.
+type tuiFrame struct {
+	Name    string
+	Col     int
+	Row     int
+	Width   int
+	Total   uint64
+	Percent float64
+	Fill    color.Color
+	Depth   int
+	Path    string
+}
+
+// NewModel constructs a flamegraph tab model with default state.
+func NewModel(liveTrie LiveTrieSource) Model {
+	searchInput := textinput.New()
+	searchInput.Prompt = "/"
+	searchInput.CharLimit = 0
+	searchInput.SetWidth(32)
+	searchInput.SetStyles(textinput.DefaultStyles(true))
+
+	m := Model{
+		liveTrie:      liveTrie,
+		matchIndices:  make(map[int]bool),
+		filterVisible: make(map[int]bool),
+		subtreeSet:    make(map[int]bool),
+		searchInput:   searchInput,
+		fieldPresets: [][]string{
+			{"comm", "tracepoint", "path"},
+			{"path", "tracepoint", "comm"},
+			{"tracepoint", "comm", "path"},
+			{"pid", "tracepoint", "path"},
+			{"comm", "path", "tracepoint"},
+		},
+		isDark:     true,
+		keys:       defaultFlameKeyMap(),
+		animation:  NewAnimationState(30, 6.0, 1.0),
+		countField: "count",
+	}
+	m.syncFieldPresetToTrie()
+	m.syncCountFieldToTrie()
+	return m
+}
+
+// Init starts the flamegraph model.
+func (m Model) Init() tea.Cmd {
+	return nil
+}
+
+// Update handles incoming messages.
+func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case animTickMsg:
+		if !m.animating {
+			return m, nil
+		}
+		m.animating = m.animation.Tick(0)
+		m.frames = m.animation.CurrentFrames()
+		m.clampSelection()
+		m.subtreeSet = computeSubtreeSetInto(m.frames, m.selectedIdx, m.subtreeSet)
+		if m.animating {
+			return m, animTickCmd()
+		}
+		return m, nil
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+		m.rebuildFrames(true)
+		if m.animating {
+			return m, animTickCmd()
+		}
+		return m, nil
+	case tea.KeyPressMsg:
+		if m.searchActive {
+			handled := false
+			switch msg.String() {
+			case "esc":
+				handled = true
+				m.clearSearch()
+				m.recordKeyDebug(msg, handled, false)
+				return m, nil
+			case "enter":
+				handled = true
+				m.applySearchQuery(m.searchInput.Value())
+				m.searchActive = false
+				m.searchInput.Blur()
+				m.recordKeyDebug(msg, handled, false)
+				return m, nil
+			}
+			var cmd tea.Cmd
+			m.searchInput, cmd = m.searchInput.Update(msg)
+			_ = cmd
+			m.recordKeyDebug(msg, true, false)
+			return m, nil
+		}
+
+		prev := m.selectedIdx
+		handled := false
+		switch {
+		case isSearchOpenKey(msg):
+			handled = true
+			m.openSearch()
+		case isNextMatchKey(msg):
+			handled = true
+			m.jumpMatch(1)
+		case isPrevMatchKey(msg):
+			handled = true
+			m.jumpMatch(-1)
+		case isPauseKey(msg):
+			handled = true
+			m.togglePause()
+		case isResetBaselineKey(msg):
+			handled = true
+			m.resetBaseline()
+		case isCycleOrderKey(msg):
+			handled = true
+			m.cycleFieldOrder()
+		case isCycleMetricKey(msg):
+			handled = true
+			m.toggleCountField()
+		case isHelpToggleKey(msg):
+			handled = true
+			m.toggleHelp()
+		case isZoomInKey(msg, m.keys):
+			handled = true
+			m.zoomIn()
+		case isZoomUndoKey(msg, m.keys):
+			handled = true
+			m.zoomUndo()
+		case isZoomResetKey(msg, m.keys):
+			handled = true
+			m.zoomReset()
+		case isMoveShallowerKey(msg, m.keys):
+			handled = true
+			m.moveVerticalWithFallback(-1, 1, -1)
+		case isMoveDeeperKey(msg, m.keys):
+			handled = true
+			m.moveVerticalWithFallback(1, -1, 1)
+		case isPrevSiblingKey(msg, m.keys):
+			handled = true
+			m.moveSibling(-1)
+		case isNextSiblingKey(msg, m.keys):
+			handled = true
+			m.moveSibling(1)
+		case isJumpTopKey(msg, m.keys):
+			handled = true
+			m.jumpToTop()
+		case isJumpRootKey(msg, m.keys):
+			handled = true
+			m.jumpToRoot()
+		}
+		if m.selectedIdx != prev {
+			m.subtreeSet = computeSubtreeSetInto(m.frames, m.selectedIdx, m.subtreeSet)
+		}
+		m.recordKeyDebug(msg, handled, m.selectedIdx != prev)
+	}