Merge branch 'main' into feat/bar-panel

* test: added unit tests for uplot config builders

* test: added more tests

* test: updated tests

* fix: updated tests

* fix: fixed failing test

* fix: updated tests

* test: added test for axis

* chore: added test for thresholds with different scale key

* chore: pr review comments

* chore: pr review comments

* fix: fixed axis tests

---------

Co-authored-by: Ashwin Bhatkal <ashwin96@gmail.com>

frontend/__mocks__/uplotMock.ts

@@ -12,6 +12,8 @@ export interface MockUPlotInstance {
 export interface MockUPlotPaths {
 	spline: jest.Mock;
 	bars: jest.Mock;
+	linear: jest.Mock;
+	stepped: jest.Mock;
 }
 
 // Create mock instance methods
@@ -23,10 +25,23 @@ const createMockUPlotInstance = (): MockUPlotInstance => ({
 	setSeries: jest.fn(),
 });
 
-// Create mock paths
-const mockPaths: MockUPlotPaths = {
-	spline: jest.fn(),
-	bars: jest.fn(),
+// Path builder: (self, seriesIdx, idx0, idx1) => paths or null
+const createMockPathBuilder = (name: string): jest.Mock =>
+	jest.fn(() => ({
+		name, // To test if the correct pathBuilder is used
+		stroke: jest.fn(),
+		fill: jest.fn(),
+		clip: jest.fn(),
+	}));
+
+// Create mock paths - linear, spline, stepped needed by UPlotSeriesBuilder.getPathBuilder
+const mockPaths = {
+	spline: jest.fn(() => createMockPathBuilder('spline')),
+	bars: jest.fn(() => createMockPathBuilder('bars')),
+	linear: jest.fn(() => createMockPathBuilder('linear')),
+	stepped: jest.fn((opts?: { align?: number }) =>
+		createMockPathBuilder(`stepped-(${opts?.align ?? 0})`),
+	),
 };
 
 // Mock static methods

frontend/src/container/DashboardContainer/visualization/charts/BarChart/BarChart.tsx

@@ -0,0 +1,117 @@
+import { useCallback, useLayoutEffect, useMemo, useRef } from 'react';
+import ChartWrapper from 'container/DashboardContainer/visualization/charts/ChartWrapper/ChartWrapper';
+import BarChartTooltip from 'lib/uPlotV2/components/Tooltip/BarChartTooltip';
+import {
+	BarTooltipProps,
+	TooltipRenderArgs,
+} from 'lib/uPlotV2/components/types';
+import { has } from 'lodash-es';
+import uPlot from 'uplot';
+
+import { BarChartProps } from '../types';
+import { stack } from './stackUtils';
+
+/** Returns true if the series at the given index is hidden (e.g. via legend toggle) */
+function isSeriesHidden(plot: uPlot, seriesIndex: number): boolean {
+	return !plot.series[seriesIndex]?.show;
+}
+
+export default function BarChart(props: BarChartProps): JSX.Element {
+	const { children, isStackedBarChart, config, data, ...rest } = props;
+
+	// Store unstacked source data so uPlot hooks can access it (hooks run outside React's render cycle)
+	const unstackedDataRef = useRef<uPlot.AlignedData | null>(null);
+	unstackedDataRef.current = isStackedBarChart ? data : null;
+
+	// Prevents re-entrant calls when we update chart data (avoids infinite loop in setData hook)
+	const isUpdatingChartRef = useRef(false);
+
+	const chartData = useMemo((): uPlot.AlignedData => {
+		if (!isStackedBarChart || !data || data.length < 2) {
+			return data as uPlot.AlignedData;
+		}
+		const noSeriesHidden = (): boolean => false; // include all series in initial stack
+		const { data: stacked } = stack(data as uPlot.AlignedData, noSeriesHidden);
+		return stacked;
+	}, [data, isStackedBarChart]);
+
+	const applyStackingToChart = useCallback((plot: uPlot): void => {
+		const unstacked = unstackedDataRef.current;
+		const hasValidData =
+			unstacked && plot.data && unstacked[0]?.length === plot.data[0]?.length;
+
+		if (!hasValidData || isUpdatingChartRef.current) {
+			return;
+		}
+
+		const shouldExcludeSeries = (idx: number): boolean =>
+			isSeriesHidden(plot, idx);
+		const { data: stacked, bands } = stack(unstacked, shouldExcludeSeries);
+
+		plot.delBand(null);
+		bands.forEach((band: uPlot.Band) => plot.addBand(band));
+
+		isUpdatingChartRef.current = true;
+		plot.setData(stacked);
+		isUpdatingChartRef.current = false;
+	}, []);
+
+	useLayoutEffect(() => {
+		if (!isStackedBarChart || !config) {
+			return undefined;
+		}
+
+		const onDataChange = (plot: uPlot): void => {
+			if (!isUpdatingChartRef.current) {
+				applyStackingToChart(plot);
+			}
+		};
+
+		const onSeriesVisibilityChange = (
+			plot: uPlot,
+			_seriesIdx: number | null,
+			opts: uPlot.Series,
+		): void => {
+			if (has(opts, 'focus')) {
+				return;
+			}
+			applyStackingToChart(plot);
+		};
+
+		const removeSetDataHook = config.addHook('setData', onDataChange);
+		const removeSetSeriesHook = config.addHook(
+			'setSeries',
+			onSeriesVisibilityChange,
+		);
+
+		return (): void => {
+			removeSetDataHook?.();
+			removeSetSeriesHook?.();
+		};
+	}, [isStackedBarChart, config, applyStackingToChart]);
+
+	const renderTooltip = useCallback(
+		(props: TooltipRenderArgs): React.ReactNode => {
+			const tooltipProps: BarTooltipProps = {
+				...props,
+				timezone: rest.timezone,
+				yAxisUnit: rest.yAxisUnit,
+				decimalPrecision: rest.decimalPrecision,
+				isStackedBarChart: isStackedBarChart,
+			};
+			return <BarChartTooltip {...tooltipProps} />;
+		},
+		[rest.timezone, rest.yAxisUnit, rest.decimalPrecision, isStackedBarChart],
+	);
+
+	return (
+		<ChartWrapper
+			{...rest}
+			config={config}
+			data={chartData}
+			renderTooltip={renderTooltip}
+		>
+			{children}
+		</ChartWrapper>
+	);
+}

frontend/src/container/DashboardContainer/visualization/charts/BarChart/stackUtils.ts

@@ -0,0 +1,57 @@
+import uPlot, { AlignedData } from 'uplot';
+
+/**
+ * Stack data cumulatively (top-down: first series = top, last = bottom).
+ * When omit(i) returns true for a series index, that series is excluded from stacking.
+ */
+export function stack(
+	data: AlignedData,
+	omit: (seriesIndex: number) => boolean,
+): { data: AlignedData; bands: uPlot.Band[] } {
+	const d0Len = data[0].length;
+	const n = data.length - 1;
+	const data2: (number | null)[][] = Array(n);
+	const accum = Array(d0Len).fill(0) as number[];
+
+	// Accumulate from last series upward: last = raw, first = total
+	for (let i = n; i >= 1; i--) {
+		const seriesData = data[i] as (number | null)[];
+		if (omit(i)) {
+			data2[i - 1] = seriesData;
+		} else {
+			data2[i - 1] = seriesData.map((v, idx) => {
+				const val = v == null ? 0 : Number(v);
+				return (accum[idx] += val);
+			});
+		}
+	}
+
+	const bands: uPlot.Band[] = [];
+	// Bands: [upper, lower] - fill between consecutive visible series
+	for (let i = 1; i < data.length; i++) {
+		if (!omit(i)) {
+			const nextIdx = data.findIndex((_, j) => j > i && !omit(j));
+			if (nextIdx >= 1) {
+				bands.push({ series: [i, nextIdx] });
+			}
+		}
+	}
+
+	return {
+		data: [data[0], ...data2] as AlignedData,
+		bands,
+	};
+}
+
+/**
+ * Returns band indices for initial stacked state (no series omitted).
+ * Top-down: first series at top, band fills between consecutive series.
+ * uPlot band format: [upperSeriesIdx, lowerSeriesIdx].
+ */
+export function getInitialStackedBands(seriesCount: number): uPlot.Band[] {
+	const bands: uPlot.Band[] = [];
+	for (let i = 1; i < seriesCount; i++) {
+		bands.push({ series: [i, i + 1] });
+	}
+	return bands;
+}

frontend/src/container/DashboardContainer/visualization/panels/BarPanel/BarPanel.tsx

@@ -0,0 +1,154 @@
+import { useEffect, useMemo, useRef, useState } from 'react';
+import { PanelWrapperProps } from 'container/PanelWrapper/panelWrapper.types';
+import { useIsDarkMode } from 'hooks/useDarkMode';
+import { useResizeObserver } from 'hooks/useDimensions';
+import { LegendPosition } from 'lib/uPlotV2/components/types';
+import ContextMenu from 'periscope/components/ContextMenu';
+import { useDashboard } from 'providers/Dashboard/Dashboard';
+import { useTimezone } from 'providers/Timezone';
+import { MetricRangePayloadProps } from 'types/api/metrics/getQueryRange';
+import uPlot from 'uplot';
+import { getTimeRange } from 'utils/getTimeRange';
+
+import BarChart from '../../charts/BarChart/BarChart';
+import ChartManager from '../../components/ChartManager/ChartManager';
+import { usePanelContextMenu } from '../../hooks/usePanelContextMenu';
+import { prepareBarPanelConfig, prepareBarPanelData } from './utils';
+
+function BarPanel(props: PanelWrapperProps): JSX.Element {
+	const {
+		panelMode,
+		queryResponse,
+		widget,
+		onDragSelect,
+		isFullViewMode,
+		onToggleModelHandler,
+	} = props;
+	const uPlotRef = useRef<uPlot | null>(null);
+	const { toScrollWidgetId, setToScrollWidgetId } = useDashboard();
+	const graphRef = useRef<HTMLDivElement>(null);
+	const [minTimeScale, setMinTimeScale] = useState<number>();
+	const [maxTimeScale, setMaxTimeScale] = useState<number>();
+	const containerDimensions = useResizeObserver(graphRef);
+
+	const isDarkMode = useIsDarkMode();
+	const { timezone } = useTimezone();
+
+	useEffect(() => {
+		if (toScrollWidgetId === widget.id) {
+			graphRef.current?.scrollIntoView({
+				behavior: 'smooth',
+				block: 'center',
+			});
+			graphRef.current?.focus();
+			setToScrollWidgetId('');
+		}
+	}, [toScrollWidgetId, setToScrollWidgetId, widget.id]);
+
+	useEffect((): void => {
+		const { startTime, endTime } = getTimeRange(queryResponse);
+
+		setMinTimeScale(startTime);
+		setMaxTimeScale(endTime);
+	}, [queryResponse]);
+
+	const {
+		coordinates,
+		popoverPosition,
+		onClose,
+		menuItemsConfig,
+		clickHandlerWithContextMenu,
+	} = usePanelContextMenu({
+		widget,
+		queryResponse,
+	});
+
+	const config = useMemo(() => {
+		return prepareBarPanelConfig({
+			widget,
+			isDarkMode,
+			currentQuery: widget.query,
+			onClick: clickHandlerWithContextMenu,
+			onDragSelect,
+			apiResponse: queryResponse?.data?.payload as MetricRangePayloadProps,
+			timezone,
+			panelMode,
+			minTimeScale: minTimeScale,
+			maxTimeScale: maxTimeScale,
+		});
+	}, [
+		widget,
+		isDarkMode,
+		queryResponse?.data?.payload,
+		clickHandlerWithContextMenu,
+		onDragSelect,
+		minTimeScale,
+		maxTimeScale,
+		timezone,
+		panelMode,
+	]);
+
+	const chartData = useMemo(() => {
+		if (!queryResponse?.data?.payload) {
+			return [];
+		}
+		return prepareBarPanelData(queryResponse?.data?.payload);
+	}, [queryResponse?.data?.payload]);
+
+	const layoutChildren = useMemo(() => {
+		if (!isFullViewMode) {
+			return null;
+		}
+		return (
+			<ChartManager
+				config={config}
+				alignedData={chartData}
+				yAxisUnit={widget.yAxisUnit}
+				onCancel={onToggleModelHandler}
+			/>
+		);
+	}, [
+		isFullViewMode,
+		config,
+		chartData,
+		widget.yAxisUnit,
+		onToggleModelHandler,
+	]);
+
+	return (
+		<div style={{ height: '100%', width: '100%' }} ref={graphRef}>
+			{containerDimensions.width > 0 && containerDimensions.height > 0 && (
+				<BarChart
+					config={config}
+					legendConfig={{
+						position: widget?.legendPosition ?? LegendPosition.BOTTOM,
+					}}
+					plotRef={(plot: uPlot | null): void => {
+						uPlotRef.current = plot;
+					}}
+					onDestroy={(): void => {
+						uPlotRef.current = null;
+					}}
+					yAxisUnit={widget.yAxisUnit}
+					decimalPrecision={widget.decimalPrecision}
+					timezone={timezone.value}
+					data={chartData as uPlot.AlignedData}
+					width={containerDimensions.width}
+					height={containerDimensions.height}
+					layoutChildren={layoutChildren}
+					isStackedBarChart={widget.stackedBarChart ?? false}
+				>
+					<ContextMenu
+						coordinates={coordinates}
+						popoverPosition={popoverPosition}
+						title={menuItemsConfig.header as string}
+						items={menuItemsConfig.items}
+						onClose={onClose}
+					/>
+				</BarChart>
+			)}
+		</div>
+	);
+}
+
+export default BarPanel;

frontend/src/container/DashboardContainer/visualization/panels/BarPanel/utils.ts

@@ -0,0 +1,108 @@
+import { Timezone } from 'components/CustomTimePicker/timezoneUtils';
+import { PANEL_TYPES } from 'constants/queryBuilder';
+import { getInitialStackedBands } from 'container/DashboardContainer/visualization/charts/BarChart/stackUtils';
+import { getLegend } from 'lib/dashboard/getQueryResults';
+import getLabelName from 'lib/getLabelName';
+import { OnClickPluginOpts } from 'lib/uPlotLib/plugins/onClickPlugin';
+import {
+	DrawStyle,
+	LineInterpolation,
+	LineStyle,
+	VisibilityMode,
+} from 'lib/uPlotV2/config/types';
+import { UPlotConfigBuilder } from 'lib/uPlotV2/config/UPlotConfigBuilder';
+import { Widgets } from 'types/api/dashboard/getAll';
+import { MetricRangePayloadProps } from 'types/api/metrics/getQueryRange';
+import { Query } from 'types/api/queryBuilder/queryBuilderData';
+import { QueryData } from 'types/api/widgets/getQuery';
+import { AlignedData } from 'uplot';
+
+import { PanelMode } from '../types';
+import { fillMissingXAxisTimestamps, getXAxisTimestamps } from '../utils';
+import { buildBaseConfig } from '../utils/baseConfigBuilder';
+
+export function prepareBarPanelData(
+	apiResponse: MetricRangePayloadProps,
+): AlignedData {
+	const seriesList = apiResponse?.data?.result || [];
+	const timestampArr = getXAxisTimestamps(seriesList);
+	const yAxisValuesArr = fillMissingXAxisTimestamps(timestampArr, seriesList);
+	return [timestampArr, ...yAxisValuesArr];
+}
+
+export function prepareBarPanelConfig({
+	widget,
+	isDarkMode,
+	currentQuery,
+	onClick,
+	onDragSelect,
+	apiResponse,
+	timezone,
+	panelMode,
+	minTimeScale,
+	maxTimeScale,
+}: {
+	widget: Widgets;
+	isDarkMode: boolean;
+	currentQuery: Query;
+	onClick: OnClickPluginOpts['onClick'];
+	onDragSelect: (startTime: number, endTime: number) => void;
+	apiResponse: MetricRangePayloadProps;
+	timezone: Timezone;
+	panelMode: PanelMode;
+	minTimeScale?: number;
+	maxTimeScale?: number;
+}): UPlotConfigBuilder {
+	const builder = buildBaseConfig({
+		widget,
+		isDarkMode,
+		onClick,
+		onDragSelect,
+		apiResponse,
+		timezone,
+		panelMode,
+		panelType: PANEL_TYPES.BAR,
+		minTimeScale,
+		maxTimeScale,
+	});
+
+	builder.setCursor({
+		focus: {
+			prox: 1e3,
+		},
+	});
+
+	if (widget.stackedBarChart) {
+		const seriesCount = (apiResponse?.data?.result?.length ?? 0) + 1; // +1 for 1-based uPlot series indices
+		builder.setBands(getInitialStackedBands(seriesCount));
+	}
+
+	const seriesList: QueryData[] = apiResponse?.data?.result || [];
+	seriesList.forEach((series) => {
+		const baseLabelName = getLabelName(
+			series.metric,
+			series.queryName || '', // query
+			series.legend || '',
+		);
+
+		const label = currentQuery
+			? getLegend(series, currentQuery, baseLabelName)
+			: baseLabelName;
+
+		builder.addSeries({
+			scaleKey: 'y',
+			drawStyle: DrawStyle.Bar,
+			panelType: PANEL_TYPES.BAR,
+			label: label,
+			colorMapping: widget.customLegendColors ?? {},
+			spanGaps: false,
+			lineStyle: LineStyle.Solid,
+			lineInterpolation: LineInterpolation.Spline,
+			showPoints: VisibilityMode.Never,
+			pointSize: 5,
+			isDarkMode,
+		});
+	});
+
+	return builder;
+}

frontend/src/container/PanelWrapper/constants.ts

@@ -1,5 +1,6 @@
 import { PANEL_TYPES } from 'constants/queryBuilder';
 
+import TimeSeriesPanel from '../DashboardContainer/visualization/panels/TimeSeriesPanel/TimeSeriesPanel';
 import HistogramPanelWrapper from './HistogramPanelWrapper';
 import ListPanelWrapper from './ListPanelWrapper';
 import PiePanelWrapper from './PiePanelWrapper';
@@ -8,7 +9,7 @@ import UplotPanelWrapper from './UplotPanelWrapper';
 import ValuePanelWrapper from './ValuePanelWrapper';
 
 export const PanelTypeVsPanelWrapper = {
-	[PANEL_TYPES.TIME_SERIES]: UplotPanelWrapper,
+	[PANEL_TYPES.TIME_SERIES]: TimeSeriesPanel,
 	[PANEL_TYPES.TABLE]: TablePanelWrapper,
 	[PANEL_TYPES.LIST]: ListPanelWrapper,
 	[PANEL_TYPES.VALUE]: ValuePanelWrapper,

frontend/src/lib/uPlotV2/components/Tooltip/BarChartTooltip.tsx

@@ -0,0 +1,31 @@
+import { useMemo } from 'react';
+
+import { BarTooltipProps, TooltipContentItem } from '../types';
+import Tooltip from './Tooltip';
+import { buildTooltipContent } from './utils';
+
+export default function BarChartTooltip(props: BarTooltipProps): JSX.Element {
+	const content = useMemo(
+		(): TooltipContentItem[] =>
+			buildTooltipContent({
+				data: props.uPlotInstance.data,
+				series: props.uPlotInstance.series,
+				dataIndexes: props.dataIndexes,
+				activeSeriesIndex: props.seriesIndex,
+				uPlotInstance: props.uPlotInstance,
+				yAxisUnit: props.yAxisUnit ?? '',
+				decimalPrecision: props.decimalPrecision,
+				isStackedBarChart: props.isStackedBarChart,
+			}),
+		[
+			props.uPlotInstance,
+			props.seriesIndex,
+			props.dataIndexes,
+			props.yAxisUnit,
+			props.decimalPrecision,
+			props.isStackedBarChart,
+		],
+	);
+
+	return <Tooltip {...props} content={content} />;
+}

frontend/src/lib/uPlotV2/components/Tooltip/utils.ts

@@ -25,16 +25,28 @@ export function getTooltipBaseValue({
 	index,
 	dataIndex,
 	isStackedBarChart,
+	series,
 }: {
 	data: AlignedData;
 	index: number;
 	dataIndex: number;
 	isStackedBarChart?: boolean;
+	series?: Series[];
 }): number | null {
 	let baseValue = data[index][dataIndex] ?? null;
-	if (isStackedBarChart && index + 1 < data.length && baseValue !== null) {
-		const nextValue = data[index + 1][dataIndex] ?? null;
-		if (nextValue !== null) {
+	// Top-down stacking (first series at top): raw = stacked[i] - stacked[nextVisible].
+	// When series are hidden, we must use the next *visible* series, not index+1,
+	// since hidden series keep raw values and would produce negative/wrong results.
+	if (isStackedBarChart && baseValue !== null && series) {
+		let nextVisibleIdx = -1;
+		for (let j = index + 1; j < series.length; j++) {
+			if (series[j]?.show) {
+				nextVisibleIdx = j;
+				break;
+			}
+		}
+		if (nextVisibleIdx >= 1) {
+			const nextValue = data[nextVisibleIdx][dataIndex] ?? 0;
 			baseValue = baseValue - nextValue;
 		}
 	}
@@ -80,6 +92,7 @@ export function buildTooltipContent({
 			index,
 			dataIndex,
 			isStackedBarChart,
+			series,
 		});
 
 		const isActive = index === activeSeriesIndex;

frontend/src/lib/uPlotV2/config/UPlotAxisBuilder.ts

@@ -4,12 +4,12 @@ import uPlot, { Axis } from 'uplot';
 
 import { uPlotXAxisValuesFormat } from '../../uPlotLib/utils/constants';
 import getGridColor from '../../uPlotLib/utils/getGridColor';
+import { buildYAxisSizeCalculator } from '../utils/axis';
 import { AxisProps, ConfigBuilder } from './types';
 
 const PANEL_TYPES_WITH_X_AXIS_DATETIME_FORMAT = [
 	PANEL_TYPES.TIME_SERIES,
 	PANEL_TYPES.BAR,
-	PANEL_TYPES.PIE,
 ];
 
 /**
@@ -114,81 +114,6 @@ export class UPlotAxisBuilder extends ConfigBuilder<AxisProps, Axis> {
 			: undefined;
 	}
 
-	/**
-	 * Calculate axis size from existing size property
-	 */
-	private getExistingAxisSize(
-		self: uPlot,
-		axis: Axis,
-		values: string[] | undefined,
-		axisIdx: number,
-		cycleNum: number,
-	): number {
-		const internalSize = (axis as { _size?: number })._size;
-		if (internalSize !== undefined) {
-			return internalSize;
-		}
-
-		const existingSize = axis.size;
-		if (typeof existingSize === 'function') {
-			return existingSize(self, values ?? [], axisIdx, cycleNum);
-		}
-
-		return existingSize ?? 0;
-	}
-
-	/**
-	 * Calculate text width for longest value
-	 */
-	private calculateTextWidth(
-		self: uPlot,
-		axis: Axis,
-		values: string[] | undefined,
-	): number {
-		if (!values || values.length === 0) {
-			return 0;
-		}
-
-		// Find longest value
-		const longestVal = values.reduce(
-			(acc, val) => (val.length > acc.length ? val : acc),
-			'',
-		);
-
-		if (longestVal === '' || !axis.font?.[0]) {
-			return 0;
-		}
-
-		// eslint-disable-next-line prefer-destructuring, no-param-reassign
-		self.ctx.font = axis.font[0];
-		return self.ctx.measureText(longestVal).width / devicePixelRatio;
-	}
-
-	/**
-	 * Build Y-axis dynamic size calculator
-	 */
-	private buildYAxisSizeCalculator(): uPlot.Axis.Size {
-		return (
-			self: uPlot,
-			values: string[] | undefined,
-			axisIdx: number,
-			cycleNum: number,
-		): number => {
-			const axis = self.axes[axisIdx];
-
-			// Bail out, force convergence
-			if (cycleNum > 1) {
-				return this.getExistingAxisSize(self, axis, values, axisIdx, cycleNum);
-			}
-
-			const gap = this.props.gap ?? 5;
-			let axisSize = (axis.ticks?.size ?? 0) + gap;
-			axisSize += this.calculateTextWidth(self, axis, values);
-
-			return Math.ceil(axisSize);
-		};
-	}
-
 	/**
 	 * Build dynamic size calculator for Y-axis
 	 */
@@ -202,7 +127,7 @@ export class UPlotAxisBuilder extends ConfigBuilder<AxisProps, Axis> {
 
 		// Y-axis needs dynamic sizing based on text width
 		if (scaleKey === 'y') {
-			return this.buildYAxisSizeCalculator();
+			return buildYAxisSizeCalculator(this.props.gap ?? 5);
 		}
 
 		return undefined;

frontend/src/lib/uPlotV2/config/UPlotSeriesBuilder.ts

@@ -1,8 +1,10 @@
+import { PANEL_TYPES } from 'constants/queryBuilder';
 import { themeColors } from 'constants/theme';
 import { generateColor } from 'lib/uPlotLib/utils/generateColor';
 import uPlot, { Series } from 'uplot';
 
 import {
+	BarAlignment,
 	ConfigBuilder,
 	DrawStyle,
 	LineInterpolation,
@@ -15,18 +17,39 @@ import {
  * Builder for uPlot series configuration
  * Handles creation of series settings
  */
+
+/**
+ * Path builders are static and shared across all instances of UPlotSeriesBuilder
+ */
+let builders: PathBuilders | null = null;
 export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
+	constructor(props: SeriesProps) {
+		super(props);
+		const pathBuilders = uPlot.paths;
+
+		if (!builders) {
+			const linearBuilder = pathBuilders.linear;
+			const splineBuilder = pathBuilders.spline;
+			const steppedBuilder = pathBuilders.stepped;
+
+			if (!linearBuilder || !splineBuilder || !steppedBuilder) {
+				throw new Error('Required uPlot path builders are not available');
+			}
+			builders = {
+				linear: linearBuilder(),
+				spline: splineBuilder(),
+				stepBefore: steppedBuilder({ align: -1 }),
+				stepAfter: steppedBuilder({ align: 1 }),
+			};
+		}
+	}
+
 	private buildLineConfig({
 		lineColor,
-		lineWidth,
-		lineStyle,
-		lineCap,
 	}: {
 		lineColor: string;
-		lineWidth?: number;
-		lineStyle?: LineStyle;
-		lineCap?: Series.Cap;
 	}): Partial<Series> {
+		const { lineWidth, lineStyle, lineCap } = this.props;
 		const lineConfig: Partial<Series> = {
 			stroke: lineColor,
 			width: lineWidth ?? 2,
@@ -39,21 +62,26 @@ export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
 		if (lineCap) {
 			lineConfig.cap = lineCap;
 		}
+
+		if (this.props.panelType === PANEL_TYPES.BAR) {
+			lineConfig.fill = lineColor;
+		}
+
 		return lineConfig;
 	}
 
 	/**
 	 * Build path configuration
 	 */
-	private buildPathConfig({
-		pathBuilder,
-		drawStyle,
-		lineInterpolation,
-	}: {
-		pathBuilder?: Series.PathBuilder | null;
-		drawStyle: DrawStyle;
-		lineInterpolation?: LineInterpolation;
-	}): Partial<Series> {
+	private buildPathConfig(): Partial<Series> {
+		const {
+			pathBuilder,
+			drawStyle,
+			lineInterpolation,
+			barAlignment,
+			barMaxWidth,
+			barWidthFactor,
+		} = this.props;
 		if (pathBuilder) {
 			return { paths: pathBuilder };
 		}
@@ -70,7 +98,13 @@ export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
 					idx0: number,
 					idx1: number,
 				): Series.Paths | null => {
-					const pathsBuilder = getPathBuilder(drawStyle, lineInterpolation);
+					const pathsBuilder = getPathBuilder({
+						drawStyle,
+						lineInterpolation,
+						barAlignment,
+						barMaxWidth,
+						barWidthFactor,
+					});
 
 					return pathsBuilder(self, seriesIdx, idx0, idx1);
 				},
@@ -85,21 +119,17 @@ export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
 	 */
 	private buildPointsConfig({
 		lineColor,
-		lineWidth,
-		pointSize,
-		pointsBuilder,
-		pointsFilter,
-		drawStyle,
-		showPoints,
 	}: {
 		lineColor: string;
-		lineWidth?: number;
-		pointSize?: number;
-		pointsBuilder: Series.Points.Show | null;
-		pointsFilter: Series.Points.Filter | null;
-		drawStyle: DrawStyle;
-		showPoints?: VisibilityMode;
 	}): Partial<Series.Points> {
+		const {
+			lineWidth,
+			pointSize,
+			pointsBuilder,
+			pointsFilter,
+			drawStyle,
+			showPoints,
+		} = this.props;
 		const pointsConfig: Partial<Series.Points> = {
 			stroke: lineColor,
 			fill: lineColor,
@@ -136,44 +166,16 @@ export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
 	}
 
 	getConfig(): Series {
-		const {
-			drawStyle,
-			pathBuilder,
-			pointsBuilder,
-			pointsFilter,
-			lineInterpolation,
-			lineWidth,
-			lineStyle,
-			lineCap,
-			showPoints,
-			pointSize,
-			scaleKey,
-			label,
-			spanGaps,
-			show = true,
-		} = this.props;
+		const { scaleKey, label, spanGaps, show = true } = this.props;
 
 		const lineColor = this.getLineColor();
 
 		const lineConfig = this.buildLineConfig({
 			lineColor,
-			lineWidth,
-			lineStyle,
-			lineCap,
-		});
-		const pathConfig = this.buildPathConfig({
-			pathBuilder,
-			drawStyle,
-			lineInterpolation,
 		});
+		const pathConfig = this.buildPathConfig();
 		const pointsConfig = this.buildPointsConfig({
 			lineColor,
-			lineWidth,
-			pointSize,
-			pointsBuilder: pointsBuilder ?? null,
-			pointsFilter: pointsFilter ?? null,
-			drawStyle,
-			showPoints,
 		});
 
 		return {
@@ -198,35 +200,40 @@ interface PathBuilders {
 	[key: string]: Series.PathBuilder;
 }
 
-let builders: PathBuilders | null = null;
-
 /**
  * Get path builder based on draw style and interpolation
  */
-function getPathBuilder(
-	style: DrawStyle,
-	lineInterpolation?: LineInterpolation,
-): Series.PathBuilder {
+function getPathBuilder({
+	drawStyle,
+	lineInterpolation,
+	barAlignment = BarAlignment.Center,
+	barWidthFactor = 0.6,
+	barMaxWidth = 200,
+}: {
+	drawStyle: DrawStyle;
+	lineInterpolation?: LineInterpolation;
+	barAlignment?: BarAlignment;
+	barMaxWidth?: number;
+	barWidthFactor?: number;
+}): Series.PathBuilder {
 	const pathBuilders = uPlot.paths;
 
 	if (!builders) {
-		const linearBuilder = pathBuilders.linear;
-		const splineBuilder = pathBuilders.spline;
-		const steppedBuilder = pathBuilders.stepped;
-
-		if (!linearBuilder || !splineBuilder || !steppedBuilder) {
-			throw new Error('Required uPlot path builders are not available');
-		}
-
-		builders = {
-			linear: linearBuilder(),
-			spline: splineBuilder(),
-			stepBefore: steppedBuilder({ align: -1 }),
-			stepAfter: steppedBuilder({ align: 1 }),
-		};
+		throw new Error('Required uPlot path builders are not available');
 	}
 
-	if (style === DrawStyle.Line) {
+	if (drawStyle === DrawStyle.Bar) {
+		const barsCfgKey = `bars|${barAlignment}|${barWidthFactor}|${barMaxWidth}`;
+		if (!builders[barsCfgKey] && pathBuilders.bars) {
+			builders[barsCfgKey] = pathBuilders.bars({
+				size: [barWidthFactor, barMaxWidth],
+				align: barAlignment,
+			});
+		}
+		return builders[barsCfgKey];
+	}
+
+	if (drawStyle === DrawStyle.Line) {
 		if (lineInterpolation === LineInterpolation.StepBefore) {
 			return builders.stepBefore;
 		}

frontend/src/lib/uPlotV2/config/__tests__/UPlotAxisBuilder.test.ts

@@ -0,0 +1,393 @@
+import { getToolTipValue } from 'components/Graph/yAxisConfig';
+import { PANEL_TYPES } from 'constants/queryBuilder';
+import { uPlotXAxisValuesFormat } from 'lib/uPlotLib/utils/constants';
+import type uPlot from 'uplot';
+
+import type { AxisProps } from '../types';
+import { UPlotAxisBuilder } from '../UPlotAxisBuilder';
+
+jest.mock('components/Graph/yAxisConfig', () => ({
+	getToolTipValue: jest.fn(),
+}));
+
+const createAxisProps = (overrides: Partial<AxisProps> = {}): AxisProps => ({
+	scaleKey: 'x',
+	label: 'Time',
+	isDarkMode: false,
+	show: true,
+	...overrides,
+});
+
+describe('UPlotAxisBuilder', () => {
+	beforeEach(() => {
+		jest.clearAllMocks();
+	});
+
+	it('builds basic axis config with defaults', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				label: 'Time',
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.scale).toBe('x');
+		expect(config.label).toBe('Time');
+		expect(config.show).toBe(true);
+		expect(config.side).toBe(2);
+		expect(config.gap).toBe(5);
+
+		// Default grid and ticks are created
+		expect(config.grid).toEqual({
+			stroke: 'rgba(0,0,0,0.5)',
+			width: 0.2,
+			show: true,
+		});
+		expect(config.ticks).toEqual({
+			width: 0.3,
+			show: true,
+		});
+	});
+
+	it('sets config values when provided', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				label: 'Time',
+				show: false,
+				side: 0,
+				gap: 10,
+				grid: {
+					stroke: '#ff0000',
+					width: 1,
+					show: false,
+				},
+				ticks: {
+					stroke: '#00ff00',
+					width: 1,
+					show: false,
+					size: 10,
+				},
+				values: ['1', '2', '3'],
+				space: 20,
+				size: 100,
+				stroke: '#0000ff',
+			}),
+		);
+		const config = builder.getConfig();
+		expect(config.scale).toBe('x');
+		expect(config.label).toBe('Time');
+		expect(config.show).toBe(false);
+		expect(config.gap).toBe(10);
+		expect(config.grid).toEqual({
+			stroke: '#ff0000',
+			width: 1,
+			show: false,
+		});
+		expect(config.ticks).toEqual({
+			stroke: '#00ff00',
+			width: 1,
+			show: false,
+			size: 10,
+		});
+		expect(config.values).toEqual(['1', '2', '3']);
+		expect(config.space).toBe(20);
+		expect(config.size).toBe(100);
+		expect(config.stroke).toBe('#0000ff');
+	});
+
+	it('merges custom grid config over defaults and respects isDarkMode and isLogScale', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				isDarkMode: true,
+				isLogScale: true,
+				grid: {
+					width: 1,
+				},
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.grid).toEqual({
+			// stroke falls back to theme-based default when not provided
+			stroke: 'rgba(231,233,237,0.3)',
+			// provided width overrides default
+			width: 1,
+			// show falls back to default when not provided
+			show: true,
+		});
+	});
+
+	it('uses provided ticks config when present and falls back to defaults otherwise', () => {
+		const customTicks = { width: 1, show: false };
+		const withTicks = new UPlotAxisBuilder(
+			createAxisProps({
+				ticks: customTicks,
+			}),
+		);
+		const withoutTicks = new UPlotAxisBuilder(createAxisProps());
+
+		expect(withTicks.getConfig().ticks).toBe(customTicks);
+		expect(withoutTicks.getConfig().ticks).toEqual({
+			width: 0.3,
+			show: true,
+		});
+	});
+
+	it('uses time-based X-axis values formatter for time-series like panels', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				panelType: PANEL_TYPES.TIME_SERIES,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.values).toBe(uPlotXAxisValuesFormat);
+	});
+
+	it('does not attach X-axis datetime formatter when panel type is not supported', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				panelType: PANEL_TYPES.LIST, // not in PANEL_TYPES_WITH_X_AXIS_DATETIME_FORMAT
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.values).toBeUndefined();
+	});
+
+	it('builds Y-axis values formatter that delegates to getToolTipValue', () => {
+		const yBuilder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'y',
+				yAxisUnit: 'ms',
+				decimalPrecision: 3,
+			}),
+		);
+
+		const config = yBuilder.getConfig();
+		expect(typeof config.values).toBe('function');
+
+		(getToolTipValue as jest.Mock).mockImplementation(
+			(value: string, unit?: string, precision?: unknown) =>
+				`formatted:${value}:${unit}:${precision}`,
+		);
+
+		// Simulate uPlot calling the values formatter
+		const valuesFn = (config.values as unknown) as (
+			self: uPlot,
+			vals: unknown[],
+		) => string[];
+		const result = valuesFn({} as uPlot, [1, null, 2, Number.NaN]);
+
+		expect(getToolTipValue).toHaveBeenCalledTimes(2);
+		expect(getToolTipValue).toHaveBeenNthCalledWith(1, '1', 'ms', 3);
+		expect(getToolTipValue).toHaveBeenNthCalledWith(2, '2', 'ms', 3);
+
+		// Null/NaN values should map to empty strings
+		expect(result).toEqual(['formatted:1:ms:3', '', 'formatted:2:ms:3', '']);
+	});
+
+	it('adds dynamic size calculator only for Y-axis when size is not provided', () => {
+		const yBuilder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'y',
+			}),
+		);
+		const xBuilder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+			}),
+		);
+
+		const yConfig = yBuilder.getConfig();
+		const xConfig = xBuilder.getConfig();
+
+		expect(typeof yConfig.size).toBe('function');
+		expect(xConfig.size).toBeUndefined();
+	});
+
+	it('uses explicit size function when provided', () => {
+		const sizeFn: uPlot.Axis.Size = jest.fn(() => 100) as uPlot.Axis.Size;
+
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'y',
+				size: sizeFn,
+			}),
+		);
+
+		const config = builder.getConfig();
+		expect(config.size).toBe(sizeFn);
+	});
+
+	it('builds stroke color based on stroke and isDarkMode', () => {
+		const explicitStroke = new UPlotAxisBuilder(
+			createAxisProps({
+				stroke: '#ff0000',
+			}),
+		);
+		const darkStroke = new UPlotAxisBuilder(
+			createAxisProps({
+				stroke: undefined,
+				isDarkMode: true,
+			}),
+		);
+		const lightStroke = new UPlotAxisBuilder(
+			createAxisProps({
+				stroke: undefined,
+				isDarkMode: false,
+			}),
+		);
+
+		expect(explicitStroke.getConfig().stroke).toBe('#ff0000');
+		expect(darkStroke.getConfig().stroke).toBe('white');
+		expect(lightStroke.getConfig().stroke).toBe('black');
+	});
+
+	it('uses explicit values formatter when provided', () => {
+		const customValues: uPlot.Axis.Values = jest.fn(() => ['a', 'b', 'c']);
+
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'y',
+				values: customValues,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.values).toBe(customValues);
+	});
+
+	it('returns undefined values for scaleKey neither x nor y', () => {
+		const builder = new UPlotAxisBuilder(createAxisProps({ scaleKey: 'custom' }));
+
+		const config = builder.getConfig();
+
+		expect(config.values).toBeUndefined();
+	});
+
+	it('includes space in config when provided', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({ scaleKey: 'y', space: 50 }),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.space).toBe(50);
+	});
+
+	it('includes PANEL_TYPES.BAR and PANEL_TYPES.TIME_SERIES in X-axis datetime formatter', () => {
+		const barBuilder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				panelType: PANEL_TYPES.BAR,
+			}),
+		);
+		expect(barBuilder.getConfig().values).toBe(uPlotXAxisValuesFormat);
+
+		const timeSeriesBuilder = new UPlotAxisBuilder(
+			createAxisProps({
+				scaleKey: 'x',
+				panelType: PANEL_TYPES.TIME_SERIES,
+			}),
+		);
+		expect(timeSeriesBuilder.getConfig().values).toBe(uPlotXAxisValuesFormat);
+	});
+
+	it('should return the existing size when cycleNum > 1', () => {
+		const builder = new UPlotAxisBuilder(createAxisProps({ scaleKey: 'y' }));
+
+		const config = builder.getConfig();
+		const sizeFn = config.size;
+		expect(typeof sizeFn).toBe('function');
+
+		const mockAxis = {
+			_size: 80,
+			ticks: { size: 10 },
+			font: ['12px sans-serif'],
+		};
+		const mockSelf = ({
+			axes: [mockAxis],
+			ctx: { measureText: jest.fn(() => ({ width: 60 })), font: '' },
+		} as unknown) as uPlot;
+
+		const result = (sizeFn as (
+			s: uPlot,
+			v: string[],
+			a: number,
+			c: number,
+		) => number)(
+			mockSelf,
+			['100', '200'],
+			0,
+			2, // cycleNum > 1
+		);
+
+		expect(result).toBe(80);
+	});
+
+	it('should invoke the size calculator and compute from text width when cycleNum <= 1', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({ scaleKey: 'y', gap: 8 }),
+		);
+
+		const config = builder.getConfig();
+		const sizeFn = config.size;
+		expect(typeof sizeFn).toBe('function');
+
+		const mockAxis = {
+			ticks: { size: 12 },
+			font: ['12px sans-serif'],
+		};
+		const measureText = jest.fn(() => ({ width: 48 }));
+		const mockSelf = ({
+			axes: [mockAxis],
+			ctx: {
+				measureText,
+				get font() {
+					return '';
+				},
+				set font(_v: string) {
+					/* noop */
+				},
+			},
+		} as unknown) as uPlot;
+
+		const result = (sizeFn as (
+			s: uPlot,
+			v: string[],
+			a: number,
+			c: number,
+		) => number)(
+			mockSelf,
+			['10', '2000ms'],
+			0,
+			0, // cycleNum <= 1
+		);
+
+		expect(measureText).toHaveBeenCalledWith('2000ms');
+		expect(result).toBeGreaterThanOrEqual(12 + 8);
+	});
+
+	it('merge updates axis props', () => {
+		const builder = new UPlotAxisBuilder(
+			createAxisProps({ scaleKey: 'y', label: 'Original' }),
+		);
+
+		builder.merge({ label: 'Merged', yAxisUnit: 'bytes' });
+
+		const config = builder.getConfig();
+
+		expect(config.label).toBe('Merged');
+		expect(config.values).toBeDefined();
+	});
+});

frontend/src/lib/uPlotV2/config/__tests__/UPlotConfigBuilder.test.ts

@@ -0,0 +1,340 @@
+import { PANEL_TYPES } from 'constants/queryBuilder';
+import uPlot from 'uplot';
+
+import type { SeriesProps } from '../types';
+import { DrawStyle, SelectionPreferencesSource } from '../types';
+import { UPlotConfigBuilder } from '../UPlotConfigBuilder';
+
+// Mock only the real boundary that hits localStorage
+jest.mock(
+	'container/DashboardContainer/visualization/panels/utils/legendVisibilityUtils',
+	() => ({
+		getStoredSeriesVisibility: jest.fn(),
+	}),
+);
+
+const getStoredSeriesVisibilityMock = jest.requireMock(
+	'container/DashboardContainer/visualization/panels/utils/legendVisibilityUtils',
+) as {
+	getStoredSeriesVisibility: jest.Mock;
+};
+
+describe('UPlotConfigBuilder', () => {
+	beforeEach(() => {
+		jest.clearAllMocks();
+	});
+
+	const createSeriesProps = (
+		overrides: Partial<SeriesProps> = {},
+	): SeriesProps => ({
+		scaleKey: 'y',
+		label: 'Requests',
+		colorMapping: {},
+		drawStyle: DrawStyle.Line,
+		panelType: PANEL_TYPES.TIME_SERIES,
+		...overrides,
+	});
+
+	it('returns correct save selection preference flag from constructor args', () => {
+		const builder = new UPlotConfigBuilder({
+			shouldSaveSelectionPreference: true,
+		});
+
+		expect(builder.getShouldSaveSelectionPreference()).toBe(true);
+	});
+
+	it('returns widgetId from constructor args', () => {
+		const builder = new UPlotConfigBuilder({ widgetId: 'widget-123' });
+
+		expect(builder.getWidgetId()).toBe('widget-123');
+	});
+
+	it('sets tzDate from constructor and includes it in config', () => {
+		const tzDate = (ts: number): Date => new Date(ts);
+		const builder = new UPlotConfigBuilder({ tzDate });
+
+		const config = builder.getConfig();
+
+		expect(config.tzDate).toBe(tzDate);
+	});
+
+	it('does not call onDragSelect for click without drag (width === 0)', () => {
+		const onDragSelect = jest.fn();
+		const builder = new UPlotConfigBuilder({ onDragSelect });
+
+		const config = builder.getConfig();
+		const setSelectHooks = config.hooks?.setSelect ?? [];
+		expect(setSelectHooks.length).toBe(1);
+
+		const uplotInstance = ({
+			select: { left: 10, width: 0 },
+			posToVal: jest.fn(),
+		} as unknown) as uPlot;
+
+		// Simulate uPlot calling the hook
+		const setSelectHook = setSelectHooks[0];
+		setSelectHook!(uplotInstance);
+
+		expect(onDragSelect).not.toHaveBeenCalled();
+	});
+
+	it('calls onDragSelect with start and end times in milliseconds for a drag selection', () => {
+		const onDragSelect = jest.fn();
+		const builder = new UPlotConfigBuilder({ onDragSelect });
+
+		const config = builder.getConfig();
+		const setSelectHooks = config.hooks?.setSelect ?? [];
+		expect(setSelectHooks.length).toBe(1);
+
+		const posToVal = jest
+			.fn()
+			// left position
+			.mockReturnValueOnce(100)
+			// left + width
+			.mockReturnValueOnce(110);
+
+		const uplotInstance = ({
+			select: { left: 50, width: 20 },
+			posToVal,
+		} as unknown) as uPlot;
+
+		const setSelectHook = setSelectHooks[0];
+		setSelectHook!(uplotInstance);
+
+		expect(onDragSelect).toHaveBeenCalledTimes(1);
+		// 100 and 110 seconds converted to milliseconds
+		expect(onDragSelect).toHaveBeenCalledWith(100_000, 110_000);
+	});
+
+	it('adds and removes hooks via addHook, and exposes them through getConfig', () => {
+		const builder = new UPlotConfigBuilder();
+		const drawHook = jest.fn();
+
+		const remove = builder.addHook('draw', drawHook as uPlot.Hooks.Defs['draw']);
+
+		let config = builder.getConfig();
+		expect(config.hooks?.draw).toContain(drawHook);
+
+		// Remove and ensure it no longer appears in config
+		remove();
+		config = builder.getConfig();
+		expect(config.hooks?.draw ?? []).not.toContain(drawHook);
+	});
+
+	it('adds axes, scales, and series and wires them into the final config', () => {
+		const builder = new UPlotConfigBuilder();
+
+		// Add axis and scale
+		builder.addAxis({ scaleKey: 'y', label: 'Requests' });
+		builder.addScale({ scaleKey: 'y' });
+
+		// Add two series – legend indices should start from 1 (0 is the timestamp series)
+		builder.addSeries(createSeriesProps({ label: 'Requests' }));
+		builder.addSeries(createSeriesProps({ label: 'Errors' }));
+
+		const config = builder.getConfig();
+
+		// Axes
+		expect(config.axes).toHaveLength(1);
+		expect(config.axes?.[0].scale).toBe('y');
+
+		// Scales are returned as an object keyed by scaleKey
+		expect(config.scales).toBeDefined();
+		expect(Object.keys(config.scales ?? {})).toContain('y');
+
+		// Series: base timestamp + 2 data series
+		expect(config.series).toHaveLength(3);
+		// Base series (index 0) has a value formatter that returns empty string
+		const baseSeries = config.series?.[0] as { value?: () => string };
+		expect(typeof baseSeries?.value).toBe('function');
+		expect(baseSeries?.value?.()).toBe('');
+
+		// Legend items align with series and carry label and color from series config
+		const legendItems = builder.getLegendItems();
+		expect(Object.keys(legendItems)).toEqual(['1', '2']);
+		expect(legendItems[1].seriesIndex).toBe(1);
+		expect(legendItems[1].label).toBe('Requests');
+		expect(legendItems[2].label).toBe('Errors');
+	});
+
+	it('merges axis when addAxis is called twice with same scaleKey', () => {
+		const builder = new UPlotConfigBuilder();
+
+		builder.addAxis({ scaleKey: 'y', label: 'Requests' });
+		builder.addAxis({ scaleKey: 'y', label: 'Updated Label', show: false });
+
+		const config = builder.getConfig();
+
+		expect(config.axes).toHaveLength(1);
+		expect(config.axes?.[0].label).toBe('Updated Label');
+		expect(config.axes?.[0].show).toBe(false);
+	});
+
+	it('merges scale when addScale is called twice with same scaleKey', () => {
+		const builder = new UPlotConfigBuilder();
+
+		builder.addScale({ scaleKey: 'y', min: 0 });
+		builder.addScale({ scaleKey: 'y', max: 100 });
+
+		const config = builder.getConfig();
+
+		// Only one scale entry for 'y' (merge path used, no duplicate added)
+		expect(config.scales).toBeDefined();
+		const scales = config.scales ?? {};
+		expect(Object.keys(scales)).toEqual(['y']);
+		expect(scales.y?.range).toBeDefined();
+	});
+
+	it('restores visibility state from localStorage when selectionPreferencesSource is LOCAL_STORAGE', () => {
+		const visibilityMap = new Map<string, boolean>([
+			['Requests', true],
+			['Errors', false],
+		]);
+
+		getStoredSeriesVisibilityMock.getStoredSeriesVisibility.mockReturnValue(
+			visibilityMap,
+		);
+
+		const builder = new UPlotConfigBuilder({
+			widgetId: 'widget-1',
+			selectionPreferencesSource: SelectionPreferencesSource.LOCAL_STORAGE,
+		});
+
+		builder.addSeries(createSeriesProps({ label: 'Requests' }));
+		builder.addSeries(createSeriesProps({ label: 'Errors' }));
+
+		const legendItems = builder.getLegendItems();
+
+		// When any series is hidden, legend visibility is driven by the stored map
+		expect(legendItems[1].show).toBe(true);
+		expect(legendItems[2].show).toBe(false);
+
+		const config = builder.getConfig();
+		const [, firstSeries, secondSeries] = config.series ?? [];
+
+		expect(firstSeries?.show).toBe(true);
+		expect(secondSeries?.show).toBe(false);
+	});
+
+	it('does not attempt to read stored visibility when using in-memory preferences', () => {
+		const builder = new UPlotConfigBuilder({
+			widgetId: 'widget-1',
+			selectionPreferencesSource: SelectionPreferencesSource.IN_MEMORY,
+		});
+
+		builder.addSeries(createSeriesProps({ label: 'Requests' }));
+
+		builder.getLegendItems();
+		builder.getConfig();
+
+		expect(
+			getStoredSeriesVisibilityMock.getStoredSeriesVisibility,
+		).not.toHaveBeenCalled();
+	});
+
+	it('adds thresholds only once per scale key', () => {
+		const builder = new UPlotConfigBuilder();
+
+		const thresholdsOptions = {
+			scaleKey: 'y',
+			thresholds: [{ thresholdValue: 100 }],
+		};
+
+		builder.addThresholds(thresholdsOptions);
+		builder.addThresholds(thresholdsOptions);
+
+		const config = builder.getConfig();
+		const drawHooks = config.hooks?.draw ?? [];
+
+		// Only a single draw hook should be registered for the same scaleKey
+		expect(drawHooks.length).toBe(1);
+	});
+
+	it('adds multiple thresholds when scale key is different', () => {
+		const builder = new UPlotConfigBuilder();
+
+		const thresholdsOptions = {
+			scaleKey: 'y',
+			thresholds: [{ thresholdValue: 100 }],
+		};
+		builder.addThresholds(thresholdsOptions);
+		const thresholdsOptions2 = {
+			scaleKey: 'y2',
+			thresholds: [{ thresholdValue: 200 }],
+		};
+		builder.addThresholds(thresholdsOptions2);
+
+		const config = builder.getConfig();
+		const drawHooks = config.hooks?.draw ?? [];
+
+		// Two draw hooks should be registered for different scaleKeys
+		expect(drawHooks.length).toBe(2);
+	});
+
+	it('merges cursor configuration with defaults instead of replacing them', () => {
+		const builder = new UPlotConfigBuilder();
+
+		builder.setCursor({
+			drag: { setScale: false },
+		});
+
+		const config = builder.getConfig();
+
+		expect(config.cursor?.drag?.setScale).toBe(false);
+		// Points configuration from DEFAULT_CURSOR_CONFIG should still be present
+		expect(config.cursor?.points).toBeDefined();
+	});
+
+	it('adds plugins and includes them in config', () => {
+		const builder = new UPlotConfigBuilder();
+		const plugin: uPlot.Plugin = {
+			opts: (): void => {},
+			hooks: {},
+		};
+
+		builder.addPlugin(plugin);
+
+		const config = builder.getConfig();
+
+		expect(config.plugins).toContain(plugin);
+	});
+
+	it('sets padding, legend, focus, select, tzDate, bands and includes them in config', () => {
+		const tzDate = (ts: number): Date => new Date(ts);
+		const builder = new UPlotConfigBuilder();
+
+		const bands: uPlot.Band[] = [{ series: [1, 2], fill: (): string => '#000' }];
+
+		builder.setBands(bands);
+		builder.setPadding([10, 20, 30, 40]);
+		builder.setLegend({ show: true, live: true });
+		builder.setFocus({ alpha: 0.5 });
+		builder.setSelect({ left: 0, width: 0, top: 0, height: 0 });
+		builder.setTzDate(tzDate);
+
+		const config = builder.getConfig();
+
+		expect(config.bands).toEqual(bands);
+		expect(config.padding).toEqual([10, 20, 30, 40]);
+		expect(config.legend).toEqual({ show: true, live: true });
+		expect(config.focus).toEqual({ alpha: 0.5 });
+		expect(config.select).toEqual({ left: 0, width: 0, top: 0, height: 0 });
+		expect(config.tzDate).toBe(tzDate);
+	});
+
+	it('does not include plugins when none added', () => {
+		const builder = new UPlotConfigBuilder();
+
+		const config = builder.getConfig();
+
+		expect(config.plugins).toBeUndefined();
+	});
+
+	it('does not include bands when empty', () => {
+		const builder = new UPlotConfigBuilder();
+
+		const config = builder.getConfig();
+
+		expect(config.bands).toBeUndefined();
+	});
+});

frontend/src/lib/uPlotV2/config/__tests__/UPlotScaleBuilder.test.ts

@@ -0,0 +1,236 @@
+import type uPlot from 'uplot';
+
+import * as scaleUtils from '../../utils/scale';
+import type { ScaleProps } from '../types';
+import { DistributionType } from '../types';
+import { UPlotScaleBuilder } from '../UPlotScaleBuilder';
+
+const createScaleProps = (overrides: Partial<ScaleProps> = {}): ScaleProps => ({
+	scaleKey: 'y',
+	time: false,
+	auto: undefined,
+	min: undefined,
+	max: undefined,
+	softMin: undefined,
+	softMax: undefined,
+	distribution: DistributionType.Linear,
+	...overrides,
+});
+
+describe('UPlotScaleBuilder', () => {
+	const getFallbackMinMaxSpy = jest.spyOn(
+		scaleUtils,
+		'getFallbackMinMaxTimeStamp',
+	);
+
+	beforeEach(() => {
+		jest.clearAllMocks();
+	});
+
+	it('initializes softMin/softMax correctly when both are 0 (treated as unset)', () => {
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				softMin: 0,
+				softMax: 0,
+			}),
+		);
+
+		// Non-time scale so config path uses thresholds pipeline; we just care that
+		// adjustSoftLimitsWithThresholds receives null soft limits instead of 0/0.
+		const adjustSpy = jest.spyOn(scaleUtils, 'adjustSoftLimitsWithThresholds');
+
+		builder.getConfig();
+
+		expect(adjustSpy).toHaveBeenCalledWith(null, null, undefined, undefined);
+	});
+
+	it('handles time scales using explicit min/max and rounds max down to the previous minute', () => {
+		const min = 1_700_000_000; // seconds
+		const max = 1_700_000_600; // seconds
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				scaleKey: 'x',
+				time: true,
+				min,
+				max,
+			}),
+		);
+
+		const config = builder.getConfig();
+		const xScale = config.x;
+
+		expect(xScale.time).toBe(true);
+		expect(xScale.auto).toBe(false);
+		expect(Array.isArray(xScale.range)).toBe(true);
+
+		const [resolvedMin, resolvedMax] = xScale.range as [number, number];
+
+		// min is passed through
+		expect(resolvedMin).toBe(min);
+
+		// max is coerced to "endTime - 1 minute" and rounded down to minute precision
+		const oneMinuteAgoTimestamp = (max - 60) * 1000;
+		const currentDate = new Date(oneMinuteAgoTimestamp);
+		currentDate.setSeconds(0);
+		currentDate.setMilliseconds(0);
+		const expectedMax = Math.floor(currentDate.getTime() / 1000);
+
+		expect(resolvedMax).toBe(expectedMax);
+	});
+
+	it('falls back to getFallbackMinMaxTimeStamp when time scale has no min/max', () => {
+		getFallbackMinMaxSpy.mockReturnValue({
+			fallbackMin: 100,
+			fallbackMax: 200,
+		});
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				scaleKey: 'x',
+				time: true,
+				min: undefined,
+				max: undefined,
+			}),
+		);
+
+		const config = builder.getConfig();
+		const [resolvedMin, resolvedMax] = config.x.range as [number, number];
+
+		expect(getFallbackMinMaxSpy).toHaveBeenCalled();
+		expect(resolvedMin).toBe(100);
+		// max is aligned to "fallbackMax - 60 seconds" minute boundary
+		expect(resolvedMax).toBeLessThanOrEqual(200);
+		expect(resolvedMax).toBeGreaterThan(100);
+	});
+
+	it('pipes limits through soft-limit adjustment and log-scale normalization before range config', () => {
+		const adjustSpy = jest.spyOn(scaleUtils, 'adjustSoftLimitsWithThresholds');
+		const normalizeSpy = jest.spyOn(scaleUtils, 'normalizeLogScaleLimits');
+		const getRangeConfigSpy = jest.spyOn(scaleUtils, 'getRangeConfig');
+
+		const thresholds = {
+			scaleKey: 'y',
+			thresholds: [{ thresholdValue: 10 }],
+			yAxisUnit: 'ms',
+		};
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				softMin: 1,
+				softMax: 5,
+				min: 0,
+				max: 100,
+				distribution: DistributionType.Logarithmic,
+				thresholds,
+				logBase: 2,
+				padMinBy: 0.1,
+				padMaxBy: 0.2,
+			}),
+		);
+
+		builder.getConfig();
+
+		expect(adjustSpy).toHaveBeenCalledWith(1, 5, thresholds.thresholds, 'ms');
+		expect(normalizeSpy).toHaveBeenCalledWith({
+			distr: DistributionType.Logarithmic,
+			logBase: 2,
+			limits: {
+				min: 0,
+				max: 100,
+				softMin: expect.anything(),
+				softMax: expect.anything(),
+			},
+		});
+		expect(getRangeConfigSpy).toHaveBeenCalled();
+	});
+
+	it('computes distribution config for non-time scales and wires range function when range is not provided', () => {
+		const createRangeFnSpy = jest.spyOn(scaleUtils, 'createRangeFunction');
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				scaleKey: 'y',
+				time: false,
+				distribution: DistributionType.Linear,
+			}),
+		);
+
+		const config = builder.getConfig();
+		const yScale = config.y;
+
+		expect(createRangeFnSpy).toHaveBeenCalled();
+
+		// range should be a function when not provided explicitly
+		expect(typeof yScale.range).toBe('function');
+
+		// distribution config should be applied
+		expect(yScale.distr).toBeDefined();
+		expect(yScale.log).toBeDefined();
+	});
+
+	it('respects explicit range function when provided on props', () => {
+		const explicitRange: uPlot.Scale.Range = jest.fn(() => [
+			0,
+			10,
+		]) as uPlot.Scale.Range;
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				scaleKey: 'y',
+				range: explicitRange,
+			}),
+		);
+
+		const config = builder.getConfig();
+		const yScale = config.y;
+
+		expect(yScale.range).toBe(explicitRange);
+	});
+
+	it('derives auto flag when not explicitly provided, based on hasFixedRange and time', () => {
+		const getRangeConfigSpy = jest.spyOn(scaleUtils, 'getRangeConfig');
+
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				min: 0,
+				max: 100,
+				time: false,
+			}),
+		);
+
+		const config = builder.getConfig();
+		const yScale = config.y;
+
+		expect(getRangeConfigSpy).toHaveBeenCalled();
+		// For non-time scale with fixed min/max, hasFixedRange is true → auto should remain false
+		expect(yScale.auto).toBe(false);
+	});
+
+	it('merge updates internal min/max/soft limits while preserving other props', () => {
+		const builder = new UPlotScaleBuilder(
+			createScaleProps({
+				scaleKey: 'y',
+				min: 0,
+				max: 10,
+				softMin: 1,
+				softMax: 9,
+				time: false,
+			}),
+		);
+
+		builder.merge({
+			min: 2,
+			softMax: undefined,
+		});
+
+		expect(builder.props.min).toBe(2);
+		expect(builder.props.softMax).toBe(undefined);
+		expect(builder.props.max).toBe(10);
+		expect(builder.props.softMin).toBe(1);
+		expect(builder.props.time).toBe(false);
+		expect(builder.props.scaleKey).toBe('y');
+		expect(builder.props.distribution).toBe(DistributionType.Linear);
+		expect(builder.props.thresholds).toBe(undefined);
+	});
+});

frontend/src/lib/uPlotV2/config/__tests__/UPlotSeriesBuilder.test.ts

@@ -0,0 +1,295 @@
+import { PANEL_TYPES } from 'constants/queryBuilder';
+import { themeColors } from 'constants/theme';
+import uPlot from 'uplot';
+
+import type { SeriesProps } from '../types';
+import {
+	DrawStyle,
+	LineInterpolation,
+	LineStyle,
+	VisibilityMode,
+} from '../types';
+import { UPlotSeriesBuilder } from '../UPlotSeriesBuilder';
+
+const createBaseProps = (
+	overrides: Partial<SeriesProps> = {},
+): SeriesProps => ({
+	scaleKey: 'y',
+	label: 'Requests',
+	colorMapping: {},
+	drawStyle: DrawStyle.Line,
+	isDarkMode: false,
+	panelType: PANEL_TYPES.TIME_SERIES,
+	...overrides,
+});
+
+interface MockPath extends uPlot.Series.Paths {
+	name?: string;
+}
+
+describe('UPlotSeriesBuilder', () => {
+	it('maps basic props into uPlot series config', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				label: 'Latency',
+				spanGaps: true,
+				show: false,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.scale).toBe('y');
+		expect(config.label).toBe('Latency');
+		expect(config.spanGaps).toBe(true);
+		expect(config.show).toBe(false);
+		expect(config.pxAlign).toBe(true);
+		expect(typeof config.value).toBe('function');
+	});
+
+	it('uses explicit lineColor when provided, regardless of mapping', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				lineColor: '#ff00ff',
+				colorMapping: { Requests: '#00ff00' },
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.stroke).toBe('#ff00ff');
+	});
+
+	it('falls back to theme colors when no label is provided', () => {
+		const darkBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				label: undefined,
+				isDarkMode: true,
+				lineColor: undefined,
+			}),
+		);
+		const lightBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				label: undefined,
+				isDarkMode: false,
+				lineColor: undefined,
+			}),
+		);
+
+		const darkConfig = darkBuilder.getConfig();
+		const lightConfig = lightBuilder.getConfig();
+
+		expect(darkConfig.stroke).toBe(themeColors.white);
+		expect(lightConfig.stroke).toBe(themeColors.black);
+	});
+
+	it('uses colorMapping when available and no explicit lineColor is provided', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				label: 'Requests',
+				colorMapping: { Requests: '#123456' },
+				lineColor: undefined,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.stroke).toBe('#123456');
+	});
+
+	it('passes through a custom pathBuilder when provided', () => {
+		const customPaths = (jest.fn() as unknown) as uPlot.Series.PathBuilder;
+
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				pathBuilder: customPaths,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.paths).toBe(customPaths);
+	});
+
+	it('does not build line paths when drawStyle is Points, but still renders points', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Points,
+				pointSize: 4,
+				lineWidth: 2,
+				lineColor: '#aa00aa',
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(typeof config.paths).toBe('function');
+		expect(config.paths && config.paths({} as uPlot, 1, 0, 10)).toBeNull();
+
+		expect(config.points).toBeDefined();
+		expect(config.points?.stroke).toBe('#aa00aa');
+		expect(config.points?.fill).toBe('#aa00aa');
+		expect(config.points?.show).toBe(true);
+		expect(config.points?.size).toBe(4);
+	});
+
+	it('derives point size based on lineWidth and pointSize', () => {
+		const smallPointsBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				lineWidth: 4,
+				pointSize: 2,
+			}),
+		);
+		const largePointsBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				lineWidth: 2,
+				pointSize: 4,
+			}),
+		);
+
+		const smallConfig = smallPointsBuilder.getConfig();
+		const largeConfig = largePointsBuilder.getConfig();
+
+		expect(smallConfig.points?.size).toBeUndefined();
+		expect(largeConfig.points?.size).toBe(4);
+	});
+
+	it('uses pointsBuilder when provided instead of default visibility logic', () => {
+		const pointsBuilder: uPlot.Series.Points.Show = jest.fn(
+			() => true,
+		) as uPlot.Series.Points.Show;
+
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				pointsBuilder,
+				drawStyle: DrawStyle.Line,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.points?.show).toBe(pointsBuilder);
+	});
+
+	it('respects VisibilityMode for point visibility when no custom pointsBuilder is given', () => {
+		const neverPointsBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				showPoints: VisibilityMode.Never,
+			}),
+		);
+		const alwaysPointsBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				showPoints: VisibilityMode.Always,
+			}),
+		);
+
+		const neverConfig = neverPointsBuilder.getConfig();
+		const alwaysConfig = alwaysPointsBuilder.getConfig();
+
+		expect(neverConfig.points?.show).toBe(false);
+		expect(alwaysConfig.points?.show).toBe(true);
+	});
+
+	it('applies LineStyle.Dashed and lineCap to line config', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				lineStyle: LineStyle.Dashed,
+				lineCap: 'round' as CanvasLineCap,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.dash).toEqual([10, 10]);
+		expect(config.cap).toBe('round');
+	});
+
+	it('builds default paths for Line drawStyle and invokes the path builder', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				lineInterpolation: LineInterpolation.Linear,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		const result = config.paths?.({} as uPlot, 1, 0, 10);
+		expect((result as MockPath).name).toBe('linear');
+	});
+
+	it('uses StepBefore and StepAfter interpolation for line paths', () => {
+		const stepBeforeBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				lineInterpolation: LineInterpolation.StepBefore,
+			}),
+		);
+		const stepAfterBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				lineInterpolation: LineInterpolation.StepAfter,
+			}),
+		);
+
+		const stepBeforeConfig = stepBeforeBuilder.getConfig();
+		const stepAfterConfig = stepAfterBuilder.getConfig();
+		const stepBeforePath = stepBeforeConfig.paths?.({} as uPlot, 1, 0, 5);
+		const stepAfterPath = stepAfterConfig.paths?.({} as uPlot, 1, 0, 5);
+		expect((stepBeforePath as MockPath).name).toBe('stepped-(-1)');
+		expect((stepAfterPath as MockPath).name).toBe('stepped-(1)');
+	});
+
+	it('defaults to spline interpolation when lineInterpolation is Spline or undefined', () => {
+		const splineBuilder = new UPlotSeriesBuilder(
+			createBaseProps({
+				drawStyle: DrawStyle.Line,
+				lineInterpolation: LineInterpolation.Spline,
+			}),
+		);
+		const defaultBuilder = new UPlotSeriesBuilder(
+			createBaseProps({ drawStyle: DrawStyle.Line }),
+		);
+
+		const splineConfig = splineBuilder.getConfig();
+		const defaultConfig = defaultBuilder.getConfig();
+
+		const splinePath = splineConfig.paths?.({} as uPlot, 1, 0, 10);
+		const defaultPath = defaultConfig.paths?.({} as uPlot, 1, 0, 10);
+
+		expect((splinePath as MockPath).name).toBe('spline');
+		expect((defaultPath as MockPath).name).toBe('spline');
+	});
+
+	it('uses generateColor when label has no colorMapping and no lineColor', () => {
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				label: 'CustomSeries',
+				colorMapping: {},
+				lineColor: undefined,
+			}),
+		);
+
+		const config = builder.getConfig();
+		expect(config.stroke).toBe('#E64A3C');
+	});
+
+	it('passes through pointsFilter when provided', () => {
+		const pointsFilter: uPlot.Series.Points.Filter = jest.fn(
+			(_self, _seriesIdx, _show) => null,
+		);
+
+		const builder = new UPlotSeriesBuilder(
+			createBaseProps({
+				pointsFilter,
+				drawStyle: DrawStyle.Line,
+			}),
+		);
+
+		const config = builder.getConfig();
+
+		expect(config.points?.filter).toBe(pointsFilter);
+	});
+});

frontend/src/lib/uPlotV2/config/types.ts

@@ -126,7 +126,45 @@ export enum VisibilityMode {
 	Never = 'never',
 }
 
-export interface SeriesProps {
+/**
+ * Props for configuring lines
+ */
+export interface LineConfig {
+	lineColor?: string;
+	lineInterpolation?: LineInterpolation;
+	lineStyle?: LineStyle;
+	lineWidth?: number;
+	lineCap?: Series.Cap;
+}
+
+/**
+ * Alignment of bars
+ */
+export enum BarAlignment {
+	After = 1,
+	Before = -1,
+	Center = 0,
+}
+
+/**
+ * Props for configuring bars
+ */
+export interface BarConfig {
+	barAlignment?: BarAlignment;
+	barMaxWidth?: number;
+	barWidthFactor?: number;
+}
+
+/**
+ * Props for configuring points
+ */
+export interface PointsConfig {
+	pointColor?: string;
+	pointSize?: number;
+	showPoints?: VisibilityMode;
+}
+
+export interface SeriesProps extends LineConfig, PointsConfig, BarConfig {
 	scaleKey: string;
 	label?: string;
 	panelType: PANEL_TYPES;
@@ -137,20 +175,7 @@ export interface SeriesProps {
 	pointsBuilder?: Series.Points.Show;
 	show?: boolean;
 	spanGaps?: boolean;
-
 	isDarkMode?: boolean;
-
-	// Line config
-	lineColor?: string;
-	lineInterpolation?: LineInterpolation;
-	lineStyle?: LineStyle;
-	lineWidth?: number;
-	lineCap?: Series.Cap;
-
-	// Points config
-	pointColor?: string;
-	pointSize?: number;
-	showPoints?: VisibilityMode;
 }
 
 export interface LegendItem {

frontend/src/lib/uPlotV2/utils/__tests__/axis.test.ts

@@ -0,0 +1,218 @@
+import type uPlot from 'uplot';
+import { Axis } from 'uplot';
+
+import {
+	buildYAxisSizeCalculator,
+	calculateTextWidth,
+	getExistingAxisSize,
+} from '../axis';
+
+describe('axis utils', () => {
+	describe('calculateTextWidth', () => {
+		it('returns 0 when values are undefined or empty', () => {
+			const mockSelf = ({
+				ctx: {
+					measureText: jest.fn(),
+					font: '',
+				},
+			} as unknown) as uPlot;
+
+			// internally the type is string but it is an array of strings
+			const mockAxis: Axis = { font: (['12px sans-serif'] as unknown) as string };
+
+			expect(calculateTextWidth(mockSelf, mockAxis, undefined)).toBe(0);
+			expect(calculateTextWidth(mockSelf, mockAxis, [])).toBe(0);
+		});
+
+		it('returns 0 when longest value is empty string or axis has no usable font', () => {
+			const mockSelf = ({
+				ctx: {
+					measureText: jest.fn(),
+					font: '',
+				},
+			} as unknown) as uPlot;
+
+			const axisWithoutFont: Axis = { font: '' };
+			const axisWithEmptyFontArray: Axis = { font: '' };
+
+			expect(calculateTextWidth(mockSelf, axisWithoutFont, [''])).toBe(0);
+			expect(
+				calculateTextWidth(mockSelf, axisWithEmptyFontArray, ['a', 'bb']),
+			).toBe(0);
+		});
+
+		it('measures longest value using canvas context and axis font', () => {
+			const measureText = jest.fn(() => ({ width: 100 }));
+			const mockSelf = ({
+				ctx: {
+					font: '',
+					measureText,
+				},
+			} as unknown) as uPlot;
+
+			const mockAxis: Axis = { font: (['14px Arial'] as unknown) as string };
+			const values = ['1', '1234', '12'];
+			const dpr =
+				((global as unknown) as { devicePixelRatio?: number }).devicePixelRatio ??
+				1;
+
+			const result = calculateTextWidth(mockSelf, mockAxis, values);
+
+			expect(measureText).toHaveBeenCalledWith('1234');
+			expect(mockSelf.ctx.font).toBe('14px Arial');
+			expect(result).toBe(100 / dpr);
+		});
+	});
+
+	describe('getExistingAxisSize', () => {
+		it('returns internal _size when present', () => {
+			const axis: any = {
+				_size: 42,
+				size: 10,
+			};
+
+			const result = getExistingAxisSize({
+				uplotInstance: ({} as unknown) as uPlot,
+				axis,
+				axisIdx: 0,
+				cycleNum: 0,
+			});
+
+			expect(result).toBe(42);
+		});
+
+		it('invokes size function when _size is not set', () => {
+			const sizeFn = jest.fn(() => 24);
+			const axis: Axis = { size: sizeFn };
+			const instance = ({} as unknown) as uPlot;
+
+			const result = getExistingAxisSize({
+				uplotInstance: instance,
+				axis,
+				values: ['10', '20'],
+				axisIdx: 1,
+				cycleNum: 2,
+			});
+
+			expect(sizeFn).toHaveBeenCalledWith(instance, ['10', '20'], 1, 2);
+			expect(result).toBe(24);
+		});
+
+		it('returns numeric size or 0 when neither _size nor size are provided', () => {
+			const axisWithSize: Axis = { size: 16 };
+			const axisWithoutSize: Axis = {};
+			const instance = ({} as unknown) as uPlot;
+
+			expect(
+				getExistingAxisSize({
+					uplotInstance: instance,
+					axis: axisWithSize,
+					axisIdx: 0,
+					cycleNum: 0,
+				}),
+			).toBe(16);
+
+			expect(
+				getExistingAxisSize({
+					uplotInstance: instance,
+					axis: axisWithoutSize,
+					axisIdx: 0,
+					cycleNum: 0,
+				}),
+			).toBe(0);
+		});
+	});
+
+	describe('buildYAxisSizeCalculator', () => {
+		it('delegates to getExistingAxisSize when cycleNum > 1', () => {
+			const sizeCalculator = buildYAxisSizeCalculator(5);
+
+			const axis: any = {
+				_size: 80,
+				ticks: { size: 10 },
+				font: ['12px sans-serif'],
+			};
+
+			const measureText = jest.fn(() => ({ width: 60 }));
+			const self = ({
+				axes: [axis],
+				ctx: {
+					font: '',
+					measureText,
+				},
+			} as unknown) as uPlot;
+
+			if (typeof sizeCalculator === 'number') {
+				throw new Error('Size calculator is a number');
+			}
+
+			const result = sizeCalculator(self, ['10', '20'], 0, 2);
+
+			expect(result).toBe(80);
+			expect(measureText).not.toHaveBeenCalled();
+		});
+
+		it('computes size from ticks, gap and text width when cycleNum <= 1', () => {
+			const gap = 7;
+			const sizeCalculator = buildYAxisSizeCalculator(gap);
+
+			const axis: Axis = {
+				ticks: { size: 12 },
+				font: (['12px sans-serif'] as unknown) as string,
+			};
+
+			const measureText = jest.fn(() => ({ width: 50 }));
+			const self = ({
+				axes: [axis],
+				ctx: {
+					font: '',
+					measureText,
+				},
+			} as unknown) as uPlot;
+
+			const dpr =
+				((global as unknown) as { devicePixelRatio?: number }).devicePixelRatio ??
+				1;
+			const expected = Math.ceil(12 + gap + 50 / dpr);
+
+			if (typeof sizeCalculator === 'number') {
+				throw new Error('Size calculator is a number');
+			}
+
+			const result = sizeCalculator(self, ['short', 'the-longest'], 0, 0);
+			expect(measureText).toHaveBeenCalledWith('the-longest');
+			expect(result).toBe(expected);
+		});
+
+		it('uses 0 ticks size when ticks are not defined', () => {
+			const gap = 4;
+			const sizeCalculator = buildYAxisSizeCalculator(gap);
+
+			const axis: Axis = {
+				font: (['12px sans-serif'] as unknown) as string,
+			};
+
+			const measureText = jest.fn(() => ({ width: 40 }));
+			const self = ({
+				axes: [axis],
+				ctx: {
+					font: '',
+					measureText,
+				},
+			} as unknown) as uPlot;
+
+			const dpr =
+				((global as unknown) as { devicePixelRatio?: number }).devicePixelRatio ??
+				1;
+			const expected = Math.ceil(gap + 40 / dpr);
+
+			if (typeof sizeCalculator === 'number') {
+				throw new Error('Size calculator is a number');
+			}
+
+			const result = sizeCalculator(self, ['1', '123'], 0, 1);
+
+			expect(result).toBe(expected);
+		});
+	});
+});

frontend/src/lib/uPlotV2/utils/axis.ts

@@ -0,0 +1,80 @@
+import { Axis } from 'uplot';
+
+/**
+ * Calculate text width for longest value
+ */
+export function calculateTextWidth(
+	self: uPlot,
+	axis: Axis,
+	values: string[] | undefined,
+): number {
+	if (!values || values.length === 0) {
+		return 0;
+	}
+
+	// Find longest value
+	const longestVal = values.reduce(
+		(acc, val) => (val.length > acc.length ? val : acc),
+		'',
+	);
+
+	if (longestVal === '' || !axis.font?.[0]) {
+		return 0;
+	}
+
+	self.ctx.font = axis.font[0];
+	return self.ctx.measureText(longestVal).width / devicePixelRatio;
+}
+
+export function getExistingAxisSize({
+	uplotInstance,
+	axis,
+	values,
+	axisIdx,
+	cycleNum,
+}: {
+	uplotInstance: uPlot;
+	axis: Axis;
+	values?: string[];
+	axisIdx: number;
+	cycleNum: number;
+}): number {
+	const internalSize = (axis as { _size?: number })._size;
+	if (internalSize !== undefined) {
+		return internalSize;
+	}
+
+	const existingSize = axis.size;
+	if (typeof existingSize === 'function') {
+		return existingSize(uplotInstance, values ?? [], axisIdx, cycleNum);
+	}
+
+	return existingSize ?? 0;
+}
+
+export function buildYAxisSizeCalculator(gap: number): uPlot.Axis.Size {
+	return (
+		self: uPlot,
+		values: string[] | undefined,
+		axisIdx: number,
+		cycleNum: number,
+	): number => {
+		const axis = self.axes[axisIdx];
+
+		// Bail out, force convergence
+		if (cycleNum > 1) {
+			return getExistingAxisSize({
+				uplotInstance: self,
+				axis,
+				values,
+				axisIdx,
+				cycleNum,
+			});
+		}
+
+		let axisSize = (axis.ticks?.size ?? 0) + gap;
+		axisSize += calculateTextWidth(self, axis, values);
+
+		return Math.ceil(axisSize);
+	};
+}