tui: address review feedback for dashboard and export

12 files changed, 146 insertions, 36 deletions

diff --git a/internal/tui/common/keys.go b/internal/tui/common/keys.go
index 0dae542..a7ded71 100644
--- a/internal/tui/common/keys.go
+++ b/internal/tui/common/keys.go
@@ -52,7 +52,11 @@ func (k KeyMap) DashboardShortHelp() []key.Binding {
 func (k KeyMap) DashboardFullHelp() [][]key.Binding {
 	return [][]key.Binding{
 		{k.One, k.Two, k.Three, k.Four, k.Five, k.Six},
-		{k.Tab, k.ShiftTab, k.Export, k.Help, k.Quit},
+		{k.Tab, k.ShiftTab, k.Export, k.Refresh, k.Help, k.Quit},
+		{
+			key.NewBinding(key.WithKeys("j/k"), key.WithHelp("j/k", "scroll")),
+			key.NewBinding(key.WithKeys("up/down"), key.WithHelp("up/down", "scroll")),
+		},
 	}
 }
 
diff --git a/internal/tui/dashboard/files.go b/internal/tui/dashboard/files.go
index c52e887..9887f45 100644
--- a/internal/tui/dashboard/files.go
+++ b/internal/tui/dashboard/files.go
@@ -1,6 +1,7 @@
 package dashboard
 
 import (
+	"fmt"
 	"ior/internal/statsengine"
 	"strconv"
 
@@ -37,8 +38,9 @@ func renderFilesWithOffset(snap *statsengine.Snapshot, width, height, offset int
 	)
 	tbl.SetHeight(syscallTableHeight(height))
 	tbl.SetWidth(tableWidth(width))
-	tbl.SetCursor(clampOffset(offset, len(rows)))
-	return tbl.View()
+	cursor := clampOffset(offset, len(rows))
+	tbl.SetCursor(cursor)
+	return tbl.View() + fmt.Sprintf("\nRow %d/%d", cursor+1, len(rows))
 }
 
 func fileRows(files []statsengine.FileSnapshot) []table.Row {
diff --git a/internal/tui/dashboard/model.go b/internal/tui/dashboard/model.go
index 9c47f4b..8eb7619 100644
--- a/internal/tui/dashboard/model.go
+++ b/internal/tui/dashboard/model.go
@@ -75,6 +75,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		)
 	case messages.StatsTickMsg:
 		m.latest = msg.Snap
+		m.syscallsOffset = clampOffset(m.syscallsOffset, m.maxSyscallsRows())
+		m.filesOffset = clampOffset(m.filesOffset, m.maxFilesRows())
+		m.processesOffset = clampOffset(m.processesOffset, m.maxProcessesRows())
 		return m, nil
 	case tea.KeyMsg:
 		return m.handleKey(msg)
@@ -86,7 +89,9 @@ func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	if m.activeTab == TabSyscalls {
 		switch msg.String() {
 		case "down", "j":
-			m.syscallsOffset++
+			if m.syscallsOffset < m.maxSyscallsRows()-1 {
+				m.syscallsOffset++
+			}
 			return m, nil
 		case "up", "k":
 			if m.syscallsOffset > 0 {
@@ -98,7 +103,9 @@ func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	if m.activeTab == TabProcesses {
 		switch msg.String() {
 		case "down", "j":
-			m.processesOffset++
+			if m.processesOffset < m.maxProcessesRows()-1 {
+				m.processesOffset++
+			}
 			return m, nil
 		case "up", "k":
 			if m.processesOffset > 0 {
@@ -110,7 +117,9 @@ func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	if m.activeTab == TabFiles {
 		switch msg.String() {
 		case "down", "j":
-			m.filesOffset++
+			if m.filesOffset < m.maxFilesRows()-1 {
+				m.filesOffset++
+			}
 			return m, nil
 		case "up", "k":
 			if m.filesOffset > 0 {
@@ -137,10 +146,34 @@ func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		m.activeTab = TabLatency
 	case key.Matches(msg, m.keys.Six):
 		m.activeTab = TabGaps
+	case key.Matches(msg, m.keys.Refresh):
+		snap := m.snapshot()
+		return m, func() tea.Msg { return messages.StatsTickMsg{Snap: snap} }
 	}
 	return m, nil
 }
 
+func (m Model) maxSyscallsRows() int {
+	if m.latest == nil {
+		return 0
+	}
+	return m.latest.SyscallsCount()
+}
+
+func (m Model) maxFilesRows() int {
+	if m.latest == nil {
+		return 0
+	}
+	return m.latest.FilesCount()
+}
+
+func (m Model) maxProcessesRows() int {
+	if m.latest == nil {
+		return 0
+	}
+	return m.latest.ProcessesCount()
+}
+
 func (m Model) snapshot() *statsengine.Snapshot {
 	if m.engine == nil {
 		return nil
@@ -171,9 +204,6 @@ func tickCmd(d time.Duration) tea.Cmd {
 }
 
 func renderActiveTab(tab Tab, snap *statsengine.Snapshot, width, height, syscallsOffset, filesOffset, processesOffset int) string {
-	_ = width
-	_ = height
-
 	if snap == nil {
 		return common.PanelStyle.Render(tab.String() + ": waiting for stats...")
 	}
diff --git a/internal/tui/dashboard/model_test.go b/internal/tui/dashboard/model_test.go
index 11cfc2b..f1e6f35 100644
--- a/internal/tui/dashboard/model_test.go
+++ b/internal/tui/dashboard/model_test.go
@@ -46,6 +46,8 @@ func TestKeySwitchingChangesActiveTab(t *testing.T) {
 func TestSyscallsTabScrollsWithJK(t *testing.T) {
 	m := NewModelWithConfig(nil, 250, common.DefaultKeyMap())
 	m.activeTab = TabSyscalls
+	snap := statsengine.NewSnapshot(nil, nil, nil, []statsengine.SyscallSnapshot{{Name: "read", Count: 1}, {Name: "write", Count: 1}}, nil, nil, statsengine.HistogramSnapshot{}, statsengine.HistogramSnapshot{})
+	m.latest = &snap
 
 	next, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
 	model := next.(Model)
@@ -63,6 +65,8 @@ func TestSyscallsTabScrollsWithJK(t *testing.T) {
 func TestProcessesTabScrollsWithJK(t *testing.T) {
 	m := NewModelWithConfig(nil, 250, common.DefaultKeyMap())
 	m.activeTab = TabProcesses
+	snap := statsengine.NewSnapshot(nil, nil, nil, nil, nil, []statsengine.ProcessSnapshot{{PID: 1}, {PID: 2}}, statsengine.HistogramSnapshot{}, statsengine.HistogramSnapshot{})
+	m.latest = &snap
 
 	next, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
 	model := next.(Model)
@@ -80,6 +84,8 @@ func TestProcessesTabScrollsWithJK(t *testing.T) {
 func TestFilesTabScrollsWithJK(t *testing.T) {
 	m := NewModelWithConfig(nil, 250, common.DefaultKeyMap())
 	m.activeTab = TabFiles
+	snap := statsengine.NewSnapshot(nil, nil, nil, nil, []statsengine.FileSnapshot{{Path: "/a"}, {Path: "/b"}}, nil, statsengine.HistogramSnapshot{}, statsengine.HistogramSnapshot{})
+	m.latest = &snap
 
 	next, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
 	model := next.(Model)
@@ -94,6 +100,40 @@ func TestFilesTabScrollsWithJK(t *testing.T) {
 	}
 }
 
+func TestScrollOffsetDoesNotGrowUnbounded(t *testing.T) {
+	m := NewModelWithConfig(nil, 250, common.DefaultKeyMap())
+	m.activeTab = TabSyscalls
+	snap := statsengine.NewSnapshot(nil, nil, nil, []statsengine.SyscallSnapshot{{Name: "read", Count: 1}, {Name: "write", Count: 1}}, nil, nil, statsengine.HistogramSnapshot{}, statsengine.HistogramSnapshot{})
+	m.latest = &snap
+
+	for i := 0; i < 50; i++ {
+		next, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
+		m = next.(Model)
+	}
+	if m.syscallsOffset != 1 {
+		t.Fatalf("expected bounded offset 1, got %d", m.syscallsOffset)
+	}
+}
+
+func TestRefreshKeyEmitsRefreshTick(t *testing.T) {
+	snap := &statsengine.Snapshot{TotalSyscalls: 13}
+	engine := &fakeSnapshotSource{snap: snap}
+	m := NewModelWithConfig(engine, 250, common.DefaultKeyMap())
+	next, cmd := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'r'}})
+	_ = next
+	if cmd == nil {
+		t.Fatalf("expected refresh command")
+	}
+	msg := cmd()
+	stats, ok := msg.(messages.StatsTickMsg)
+	if !ok {
+		t.Fatalf("expected StatsTickMsg from refresh key command, got %T", msg)
+	}
+	if stats.Snap != snap {
+		t.Fatalf("expected refreshed snapshot from engine")
+	}
+}
+
 func TestRefreshTickEmitsStatsTickMsg(t *testing.T) {
 	snap := &statsengine.Snapshot{TotalSyscalls: 9}
 	engine := &fakeSnapshotSource{snap: snap}
diff --git a/internal/tui/dashboard/overview.go b/internal/tui/dashboard/overview.go
index 8b6b13c..6d705da 100644
--- a/internal/tui/dashboard/overview.go
+++ b/internal/tui/dashboard/overview.go
@@ -6,6 +6,8 @@ import (
 	common "ior/internal/tui/common"
 	"strings"
 	"time"
+
+	"github.com/charmbracelet/lipgloss"
 )
 
 func renderOverview(snap *statsengine.Snapshot, width, height int) string {
@@ -19,7 +21,7 @@ func renderOverview(snap *statsengine.Snapshot, width, height int) string {
 	box2 := renderBytesBox(snap, boxWidth)
 	box3 := renderErrorBox(snap, boxWidth)
 
-	row := strings.Join([]string{box1, box2, box3}, "\n")
+	row := lipgloss.JoinHorizontal(lipgloss.Top, box1, box2, box3)
 	trends := fmt.Sprintf(
 		"Trends: latency %s  gap %s  throughput %s",
 		trendWithArrow(snap.LatencyTrend),
@@ -28,6 +30,7 @@ func renderOverview(snap *statsengine.Snapshot, width, height int) string {
 	)
 
 	latencySpark := "Latency: " + renderSparkline(snap.LatencySeriesNs(), sparklineWidth(width))
+	gapSpark := "Gap: " + renderSparkline(snap.GapSeriesNs(), sparklineWidth(width))
 	throughputSpark := "Throughput: " + renderSparkline(snap.ThroughputSeriesB(), sparklineWidth(width))
 	topSyscalls := "Top syscalls: " + summarizeTopSyscalls(snap)
 	topFiles := "Top files: " + summarizeTopFiles(snap)
@@ -40,6 +43,7 @@ func renderOverview(snap *statsengine.Snapshot, width, height int) string {
 			row,
 			common.HighlightStyle.Render(trends),
 			common.PanelStyle.Render(latencySpark),
+			common.PanelStyle.Render(gapSpark),
 			common.PanelStyle.Render(throughputSpark),
 			common.PanelStyle.Render(topSyscalls),
 			common.PanelStyle.Render(topFiles),
@@ -52,11 +56,16 @@ func renderOverview(snap *statsengine.Snapshot, width, height int) string {
 }
 
 func renderSyscallBox(snap *statsengine.Snapshot, width int) string {
+	generatedAt := "n/a"
+	if !snap.GeneratedAt.IsZero() {
+		generatedAt = snap.GeneratedAt.Format("15:04:05")
+	}
 	content := fmt.Sprintf(
-		"Elapsed: %s\nSyscalls: %d\nRate: %.1f/s",
+		"Elapsed: %s\nSyscalls: %d\nRate: %.1f/s\nSnapshot: %s",
 		formatElapsed(snap.Elapsed),
 		snap.TotalSyscalls,
 		snap.SyscallRatePerSec,
+		generatedAt,
 	)
 	return common.PanelStyle.Width(width).Render(content)
 }
@@ -77,10 +86,12 @@ func renderErrorBox(snap *statsengine.Snapshot, width int) string {
 		errPercent = float64(snap.TotalErrors) / float64(snap.TotalSyscalls) * 100
 	}
 	content := fmt.Sprintf(
-		"Errors: %d\nError rate: %.2f%%\nLatency mean: %.0fns",
+		"Errors: %d\nError rate: %.2f%%\nError/s: %.2f\nLatency mean: %.0fns\nGap mean: %.0fns",
 		snap.TotalErrors,
 		errPercent,
+		snap.ErrorRatePerSec,
 		snap.LatencyMeanNs,
+		snap.GapMeanNs,
 	)
 	return common.PanelStyle.Width(width).Render(content)
 }
diff --git a/internal/tui/dashboard/overview_test.go b/internal/tui/dashboard/overview_test.go
index e44b015..cee6cf2 100644
--- a/internal/tui/dashboard/overview_test.go
+++ b/internal/tui/dashboard/overview_test.go
@@ -31,6 +31,7 @@ func TestRenderOverviewIncludesCoreMetrics(t *testing.T) {
 		"Errors:",
 		"Trends:",
 		"Latency:",
+		"Gap:",
 		"Throughput:",
 		"Top syscalls:",
 		"Top files:",
diff --git a/internal/tui/dashboard/processes.go b/internal/tui/dashboard/processes.go
index d229c10..03a38f1 100644
--- a/internal/tui/dashboard/processes.go
+++ b/internal/tui/dashboard/processes.go
@@ -40,9 +40,10 @@ func renderProcessesWithOffset(snap *statsengine.Snapshot, width, height, offset
 	)
 	tbl.SetHeight(syscallTableHeight(height))
 	tbl.SetWidth(tableWidth(width))
-	tbl.SetCursor(clampOffset(offset, len(rows)))
+	cursor := clampOffset(offset, len(rows))
+	tbl.SetCursor(cursor)
 
-	out := tbl.View()
+	out := tbl.View() + fmt.Sprintf("\nRow %d/%d", cursor+1, len(rows))
 	if flags.Get().PidFilter > 0 {
 		out += "\n" + "Note: this tab is most useful with All PIDs."
 	}
diff --git a/internal/tui/dashboard/syscalls.go b/internal/tui/dashboard/syscalls.go
index f25781e..e40c2e7 100644
--- a/internal/tui/dashboard/syscalls.go
+++ b/internal/tui/dashboard/syscalls.go
@@ -45,8 +45,9 @@ func renderSyscallsWithOffset(snap *statsengine.Snapshot, width, height, offset
 	)
 	tbl.SetHeight(syscallTableHeight(height))
 	tbl.SetWidth(tableWidth(width))
-	tbl.SetCursor(clampOffset(offset, len(rows)))
-	return tbl.View()
+	cursor := clampOffset(offset, len(rows))
+	tbl.SetCursor(cursor)
+	return tbl.View() + fmt.Sprintf("\nRow %d/%d", cursor+1, len(rows))
 }
 
 func syscallRows(syscalls []statsengine.SyscallSnapshot) []table.Row {
diff --git a/internal/tui/dashboard/tabs.go b/internal/tui/dashboard/tabs.go
index 9965d1f..799e9f1 100644
--- a/internal/tui/dashboard/tabs.go
+++ b/internal/tui/dashboard/tabs.go
@@ -1,6 +1,7 @@
 package dashboard
 
 import (
+	"fmt"
 	common "ior/internal/tui/common"
 	"strings"
 
@@ -77,8 +78,8 @@ func tabIndex(tab Tab) int {
 
 func renderTabBar(active Tab, width int) string {
 	parts := make([]string, 0, len(allTabs))
-	for _, tab := range allTabs {
-		label := tab.String()
+	for i, tab := range allTabs {
+		label := fmt.Sprintf("%d:%s", i+1, tab.String())
 		if tab == active {
 			parts = append(parts, common.TabActiveStyle.Render(label))
 		} else {
diff --git a/internal/tui/export/model.go b/internal/tui/export/model.go
index 1e875e5..57612db 100644
--- a/internal/tui/export/model.go
+++ b/internal/tui/export/model.go
@@ -13,8 +13,7 @@ import (
 type Option int
 
 const (
-	OptionFlamegraph Option = iota
-	OptionCSV
+	OptionCSV Option = iota
 	OptionCancel
 )
 
diff --git a/internal/tui/pidpicker/model.go b/internal/tui/pidpicker/model.go
index 34da674..37af257 100644
--- a/internal/tui/pidpicker/model.go
+++ b/internal/tui/pidpicker/model.go
@@ -2,6 +2,7 @@ package pidpicker
 
 import (
 	"fmt"
+	common "ior/internal/tui/common"
 	"ior/internal/tui/messages"
 	"strings"
 
@@ -34,14 +35,11 @@ func (k KeyMap) PickerShortHelp() []key.Binding {
 }
 
 var (
-	screenStyle  = lipgloss.NewStyle()
-	headerStyle  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("75"))
-	helpBarStyle = lipgloss.NewStyle().
-			Foreground(lipgloss.Color("246")).
-			BorderTop(true).
-			BorderForeground(lipgloss.Color("238"))
-	highlightStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("222"))
-	errorStyle     = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("203"))
+	screenStyle    = common.ScreenStyle
+	headerStyle    = common.HeaderStyle
+	helpBarStyle   = common.HelpBarStyle
+	highlightStyle = common.HighlightStyle
+	errorStyle     = common.ErrorStyle
 )
 
 type processesLoadedMsg struct {
diff --git a/internal/tui/tui.go b/internal/tui/tui.go
index 5bc7bf9..d988fa1 100644
--- a/internal/tui/tui.go
+++ b/internal/tui/tui.go
@@ -299,12 +299,6 @@ func runExportCmd(option tuiexport.Option, snap *statsengine.Snapshot) tea.Cmd {
 				return tuiexport.FailedMsg{Err: err}
 			}
 			return tuiexport.CompletedMsg{Path: path}
-		case tuiexport.OptionFlamegraph:
-			path, err := exportFlamegraph()
-			if err != nil {
-				return tuiexport.FailedMsg{Err: err}
-			}
-			return tuiexport.CompletedMsg{Path: path}
 		default:
 			return tuiexport.FailedMsg{Err: errors.New("unknown export option")}
 		}
@@ -335,6 +329,8 @@ func exportSnapshotCSV(snap *statsengine.Snapshot) (string, error) {
 		{"section", "name", "value1", "value2", "value3"},
 		{"summary", "totals", fmt.Sprint(snapValue(snap, func(s *statsengine.Snapshot) uint64 { return s.TotalSyscalls })), fmt.Sprint(snapValue(snap, func(s *statsengine.Snapshot) uint64 { return s.TotalErrors })), fmt.Sprint(snapValue(snap, func(s *statsengine.Snapshot) uint64 { return s.TotalBytes }))},
 		{"summary", "rates_per_sec", fmt.Sprintf("%.2f", snapValueF(snap, func(s *statsengine.Snapshot) float64 { return s.SyscallRatePerSec })), fmt.Sprintf("%.2f", snapValueF(snap, func(s *statsengine.Snapshot) float64 { return s.ReadBytesPerSec })), fmt.Sprintf("%.2f", snapValueF(snap, func(s *statsengine.Snapshot) float64 { return s.WriteBytesPerSec }))},
+		{"summary", "latency_gap_mean_ns", fmt.Sprintf("%.2f", snapValueF(snap, func(s *statsengine.Snapshot) float64 { return s.LatencyMeanNs })), fmt.Sprintf("%.2f", snapValueF(snap, func(s *statsengine.Snapshot) float64 { return s.GapMeanNs })), ""},
+		{"summary", "trend", trendSummary(snap, func(s *statsengine.Snapshot) statsengine.Trend { return s.LatencyTrend }), trendSummary(snap, func(s *statsengine.Snapshot) statsengine.Trend { return s.GapTrend }), trendSummary(snap, func(s *statsengine.Snapshot) statsengine.Trend { return s.ThroughputTrend })},
 	}
 	for _, row := range rows {
 		if err := w.Write(row); err != nil {
@@ -347,16 +343,38 @@ func exportSnapshotCSV(snap *statsengine.Snapshot) (string, error) {
 			if err := w.Write([]string{"syscall", s.Name, fmt.Sprint(s.Count), fmt.Sprintf("%.2f", s.RatePerSec), fmt.Sprint(s.Bytes)}); err != nil {
 				return "", err
 			}
+			if err := w.Write([]string{"syscall_latency_ns", s.Name, fmt.Sprintf("%.2f", s.LatencyMeanNs), fmt.Sprint(s.LatencyMinNs), fmt.Sprint(s.LatencyMaxNs)}); err != nil {
+				return "", err
+			}
+			if err := w.Write([]string{"syscall_percentiles_ns", s.Name, fmt.Sprint(s.LatencyP50Ns), fmt.Sprint(s.LatencyP95Ns), fmt.Sprint(s.LatencyP99Ns)}); err != nil {
+				return "", err
+			}
 		}
 		for _, r := range snap.Files() {
 			if err := w.Write([]string{"file", r.Path, fmt.Sprint(r.Accesses), fmt.Sprint(r.BytesRead), fmt.Sprint(r.BytesWritten)}); err != nil {
 				return "", err
 			}
+			if err := w.Write([]string{"file_latency_ns", r.Path, fmt.Sprintf("%.2f", r.AvgLatencyNs), fmt.Sprint(r.MaxLatencyNs), ""}); err != nil {
+				return "", err
+			}
 		}
 		for _, p := range snap.Processes() {
 			if err := w.Write([]string{"process", fmt.Sprint(p.PID), fmt.Sprint(p.Syscalls), fmt.Sprintf("%.2f", p.RatePerSec), fmt.Sprint(p.Bytes)}); err != nil {
 				return "", err
 			}
+			if err := w.Write([]string{"process_latency_ns", fmt.Sprint(p.PID), fmt.Sprintf("%.2f", p.AvgLatencyNs), "", ""}); err != nil {
+				return "", err
+			}
+		}
+		for _, b := range snap.LatencyHistogram.Buckets() {
+			if err := w.Write([]string{"latency_hist", b.Label, fmt.Sprint(b.Count), fmt.Sprint(b.LowerNs), fmt.Sprint(b.UpperNs)}); err != nil {
+				return "", err
+			}
+		}
+		for _, b := range snap.GapHistogram.Buckets() {
+			if err := w.Write([]string{"gap_hist", b.Label, fmt.Sprint(b.Count), fmt.Sprint(b.LowerNs), fmt.Sprint(b.UpperNs)}); err != nil {
+				return "", err
+			}
 		}
 	}
 
@@ -381,8 +399,12 @@ func snapValueF(snap *statsengine.Snapshot, get func(*statsengine.Snapshot) floa
 	return get(snap)
 }
 
-func exportFlamegraph() (string, error) {
-	return "", errors.New("flamegraph export is not yet available in TUI mode")
+func trendSummary(snap *statsengine.Snapshot, get func(*statsengine.Snapshot) statsengine.Trend) string {
+	if snap == nil {
+		return "stable:0.00"
+	}
+	trend := get(snap)
+	return fmt.Sprintf("%s:%.2f", trend.Direction, trend.DeltaPercent)
 }
 
 func renderHelpOverlay(width, height int, groups [][]key.Binding) string {