Unify live metrics chart rendering

audit/internal/webui/server.go

@@ -121,6 +121,7 @@ type namedMetricsRing struct {
 // pendingNetChange tracks a network state change awaiting confirmation.
 type pendingNetChange struct {
 	snapshot platform.NetworkSnapshot
+	deadline time.Time
 	timer    *time.Timer
 	mu       sync.Mutex
 }
@@ -527,15 +528,7 @@ func (h *handler) handleMetricsChartSVG(w http.ResponseWriter, r *http.Request)
 	case path == "server-fans":
 		title = "Fan RPM"
 		h.ringsMu.Lock()
-		for i, fr := range h.ringFans {
-			fv, _ := fr.snapshot()
-			datasets = append(datasets, fv)
-			name := "Fan"
-			if i < len(h.fanNames) {
-				name = h.fanNames[i]
-			}
-			names = append(names, name+" RPM")
-		}
+		datasets, names, labels = snapshotFanRings(h.ringFans, h.fanNames)
 		h.ringsMu.Unlock()
 		yMin = floatPtr(0)
 		yMax = autoMax120(datasets...)
@@ -1044,15 +1037,17 @@ func renderChartSVG(title string, datasets [][]float64, names []string, labels [
 	opt.Title = gocharts.TitleOption{Text: title}
 	opt.XAxis.Labels = sparse
 	opt.Legend = gocharts.LegendOption{SeriesNames: names}
+	if chartLegendVisible(len(names)) {
+		opt.Legend.Offset = gocharts.OffsetStr{Top: gocharts.PositionBottom}
+		opt.Legend.OverlayChart = gocharts.Ptr(false)
+	} else {
+		opt.Legend.Show = gocharts.Ptr(false)
+	}
 	opt.Symbol = gocharts.SymbolNone
 	// Right padding: reserve space for the MarkLine label (library recommendation).
 	opt.Padding = gocharts.NewBox(20, 20, 80, 20)
 	if yMin != nil || yMax != nil {
-		opt.YAxis = []gocharts.YAxisOption{{
-			Min:            yMin,
-			Max:            yMax,
-			ValueFormatter: chartLegendNumber,
-		}}
+		opt.YAxis = []gocharts.YAxisOption{chartYAxisOption(yMin, yMax)}
 	}
 
 	// Add a single peak mark line on the series that holds the global maximum.
@@ -1064,7 +1059,7 @@ func renderChartSVG(title string, datasets [][]float64, names []string, labels [
 	p := gocharts.NewPainter(gocharts.PainterOptions{
 		OutputFormat: gocharts.ChartOutputSVG,
 		Width:        1400,
-		Height:       240,
+		Height:       chartCanvasHeight(len(names)),
 	}, gocharts.PainterThemeOption(gocharts.GetTheme("grafana")))
 	if err := p.LineChart(opt); err != nil {
 		return nil, err
@@ -1072,6 +1067,26 @@ func renderChartSVG(title string, datasets [][]float64, names []string, labels [
 	return p.Bytes()
 }
 
+func chartLegendVisible(seriesCount int) bool {
+	return seriesCount <= 8
+}
+
+func chartCanvasHeight(seriesCount int) int {
+	if chartLegendVisible(seriesCount) {
+		return 360
+	}
+	return 288
+}
+
+func chartYAxisOption(yMin, yMax *float64) gocharts.YAxisOption {
+	return gocharts.YAxisOption{
+		Min:            yMin,
+		Max:            yMax,
+		LabelCount:     11,
+		ValueFormatter: chartYAxisNumber,
+	}
+}
+
 // globalPeakSeries returns the index of the series containing the global maximum
 // value across all datasets, and that maximum value.
 func globalPeakSeries(datasets [][]float64) (idx int, peak float64) {
@@ -1159,6 +1174,28 @@ func snapshotNamedRings(rings []*namedMetricsRing) ([][]float64, []string, []str
 	return datasets, names, labels
 }
 
+func snapshotFanRings(rings []*metricsRing, fanNames []string) ([][]float64, []string, []string) {
+	var datasets [][]float64
+	var names []string
+	var labels []string
+	for i, ring := range rings {
+		if ring == nil {
+			continue
+		}
+		vals, l := ring.snapshot()
+		datasets = append(datasets, vals)
+		name := "Fan"
+		if i < len(fanNames) {
+			name = fanNames[i]
+		}
+		names = append(names, name+" RPM")
+		if len(labels) == 0 {
+			labels = l
+		}
+	}
+	return datasets, names, labels
+}
+
 func chartLegendNumber(v float64) string {
 	neg := v < 0
 	if v < 0 {
@@ -1181,6 +1218,23 @@ func chartLegendNumber(v float64) string {
 	return out
 }
 
+func chartYAxisNumber(v float64) string {
+	neg := v < 0
+	if neg {
+		v = -v
+	}
+	var out string
+	if v >= 1000 {
+		out = fmt.Sprintf("%dк", int((v+500)/1000))
+	} else {
+		out = fmt.Sprintf("%.0f", v)
+	}
+	if neg {
+		return "-" + out
+	}
+	return out
+}
+
 func sparseLabels(labels []string, n int) []string {
 	out := make([]string, len(labels))
 	step := len(labels) / n