test: added tests for barpanel hooks + utils

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

@@ -0,0 +1,45 @@
+import { useCallback } 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 { useBarChartStacking } from '../../hooks/useBarChartStacking';
+import { BarChartProps } from '../types';
+
+export default function BarChart(props: BarChartProps): JSX.Element {
+	const { children, isStackedBarChart, config, data, ...rest } = props;
+
+	const chartData = useBarChartStacking({
+		data,
+		isStackedBarChart,
+		config,
+	});
+
+	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/utils/__tests__/stackUtils.test.ts

@@ -0,0 +1,117 @@
+import { AlignedData } from 'uplot';
+
+import { getInitialStackedBands, stack } from '../stackUtils';
+
+describe('stackUtils', () => {
+	describe('stack', () => {
+		const neverOmit = (): boolean => false;
+
+		it('preserves time axis as first row', () => {
+			const data: AlignedData = [
+				[100, 200, 300],
+				[1, 2, 3],
+				[4, 5, 6],
+			];
+			const { data: result } = stack(data, neverOmit);
+			expect(result[0]).toEqual([100, 200, 300]);
+		});
+
+		it('stacks value series cumulatively (last = raw, first = total)', () => {
+			// Time, then 3 value series. Stack order: last series stays raw, then we add upward.
+			const data: AlignedData = [
+				[0, 1, 2],
+				[1, 2, 3], // series 1
+				[4, 5, 6], // series 2
+				[7, 8, 9], // series 3
+			];
+			const { data: result } = stack(data, neverOmit);
+			// result[1] = s1+s2+s3, result[2] = s2+s3, result[3] = s3
+			expect(result[1]).toEqual([12, 15, 18]); // 1+4+7, 2+5+8, 3+6+9
+			expect(result[2]).toEqual([11, 13, 15]); // 4+7, 5+8, 6+9
+			expect(result[3]).toEqual([7, 8, 9]);
+		});
+
+		it('treats null values as 0 when stacking', () => {
+			const data: AlignedData = [
+				[0, 1],
+				[1, null],
+				[null, 10],
+			];
+			const { data: result } = stack(data, neverOmit);
+			expect(result[1]).toEqual([1, 10]); // total
+			expect(result[2]).toEqual([0, 10]); // last series with null→0
+		});
+
+		it('copies omitted series as-is without accumulating', () => {
+			// Omit series 2 (index 2); series 1 and 3 are stacked.
+			const data: AlignedData = [
+				[0, 1],
+				[10, 20], // series 1
+				[100, 200], // series 2 - omitted
+				[1, 2], // series 3
+			];
+			const omitSeries2 = (i: number): boolean => i === 2;
+			const { data: result } = stack(data, omitSeries2);
+			// series 3 raw: [1, 2]; series 2 omitted: [100, 200] as-is; series 1 stacked with s3: [11, 22]
+			expect(result[1]).toEqual([11, 22]); // 10+1, 20+2
+			expect(result[2]).toEqual([100, 200]); // copied, not stacked
+			expect(result[3]).toEqual([1, 2]);
+		});
+
+		it('returns bands between consecutive visible series when none omitted', () => {
+			const data: AlignedData = [
+				[0, 1],
+				[1, 2],
+				[3, 4],
+				[5, 6],
+			];
+			const { bands } = stack(data, neverOmit);
+			expect(bands).toEqual([{ series: [1, 2] }, { series: [2, 3] }]);
+		});
+
+		it('returns bands only between visible series when some are omitted', () => {
+			// 4 value series; omit index 2. Visible: 1, 3, 4. Bands: [1,3], [3,4]
+			const data: AlignedData = [[0], [1], [2], [3], [4]];
+			const omitSeries2 = (i: number): boolean => i === 2;
+			const { bands } = stack(data, omitSeries2);
+			expect(bands).toEqual([{ series: [1, 3] }, { series: [3, 4] }]);
+		});
+
+		it('returns empty bands when only one value series', () => {
+			const data: AlignedData = [
+				[0, 1],
+				[1, 2],
+			];
+			const { bands } = stack(data, neverOmit);
+			expect(bands).toEqual([]);
+		});
+	});
+
+	describe('getInitialStackedBands', () => {
+		it('returns one band between each consecutive pair for seriesCount 3', () => {
+			expect(getInitialStackedBands(3)).toEqual([
+				{ series: [1, 2] },
+				{ series: [2, 3] },
+			]);
+		});
+
+		it('returns empty array for seriesCount 0 or 1', () => {
+			expect(getInitialStackedBands(0)).toEqual([]);
+			expect(getInitialStackedBands(1)).toEqual([]);
+		});
+
+		it('returns single band for seriesCount 2', () => {
+			expect(getInitialStackedBands(2)).toEqual([{ series: [1, 2] }]);
+		});
+
+		it('returns bands [1,2], [2,3], ..., [n-1, n] for seriesCount n', () => {
+			const bands = getInitialStackedBands(5);
+			expect(bands).toEqual([
+				{ series: [1, 2] },
+				{ series: [2, 3] },
+				{ series: [3, 4] },
+				{ series: [4, 5] },
+			]);
+		});
+	});
+});

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

@@ -0,0 +1,116 @@
+import uPlot, { AlignedData } from 'uplot';
+
+/**
+ * Stack data cumulatively (top-down: first series = top, last = bottom).
+ * When `omit(seriesIndex)` returns true, that series is excluded from stacking.
+ */
+export function stack(
+	data: AlignedData,
+	omit: (seriesIndex: number) => boolean,
+): { data: AlignedData; bands: uPlot.Band[] } {
+	const timeAxis = data[0];
+	const pointCount = timeAxis.length;
+	const valueSeriesCount = data.length - 1; // exclude time axis
+
+	const stackedSeries = buildStackedSeries({
+		data,
+		valueSeriesCount,
+		pointCount,
+		omit,
+	});
+	const bands = buildFillBands(valueSeriesCount + 1, omit); // +1 for 1-based series indices
+
+	return {
+		data: [timeAxis, ...stackedSeries] as AlignedData,
+		bands,
+	};
+}
+
+interface BuildStackedSeriesParams {
+	data: AlignedData;
+	valueSeriesCount: number;
+	pointCount: number;
+	omit: (seriesIndex: number) => boolean;
+}
+
+/**
+ * Accumulate from last series upward: last series = raw values, first = total.
+ * Omitted series are copied as-is (no accumulation).
+ */
+function buildStackedSeries({
+	data,
+	valueSeriesCount,
+	pointCount,
+	omit,
+}: BuildStackedSeriesParams): (number | null)[][] {
+	const stackedSeries: (number | null)[][] = Array(valueSeriesCount);
+	const cumulativeSums = Array(pointCount).fill(0) as number[];
+
+	for (let seriesIndex = valueSeriesCount; seriesIndex >= 1; seriesIndex--) {
+		const rawValues = data[seriesIndex] as (number | null)[];
+
+		if (omit(seriesIndex)) {
+			stackedSeries[seriesIndex - 1] = rawValues;
+		} else {
+			stackedSeries[seriesIndex - 1] = rawValues.map((rawValue, pointIndex) => {
+				const numericValue = rawValue == null ? 0 : Number(rawValue);
+				return (cumulativeSums[pointIndex] += numericValue);
+			});
+		}
+	}
+
+	return stackedSeries;
+}
+
+/**
+ * Bands define fill between consecutive visible series for stacked appearance.
+ * uPlot format: [upperSeriesIdx, lowerSeriesIdx].
+ */
+function buildFillBands(
+	seriesLength: number,
+	omit: (seriesIndex: number) => boolean,
+): uPlot.Band[] {
+	const bands: uPlot.Band[] = [];
+
+	for (let seriesIndex = 1; seriesIndex < seriesLength; seriesIndex++) {
+		if (omit(seriesIndex)) {
+			continue;
+		}
+		const nextVisibleSeriesIndex = findNextVisibleSeriesIndex(
+			seriesLength,
+			seriesIndex,
+			omit,
+		);
+		if (nextVisibleSeriesIndex !== -1) {
+			bands.push({ series: [seriesIndex, nextVisibleSeriesIndex] });
+		}
+	}
+
+	return bands;
+}
+
+function findNextVisibleSeriesIndex(
+	seriesLength: number,
+	afterIndex: number,
+	omit: (seriesIndex: number) => boolean,
+): number {
+	for (let i = afterIndex + 1; i < seriesLength; i++) {
+		if (!omit(i)) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+/**
+ * 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 seriesIndex = 1; seriesIndex < seriesCount; seriesIndex++) {
+		bands.push({ series: [seriesIndex, seriesIndex + 1] });
+	}
+	return bands;
+}

frontend/src/container/DashboardContainer/visualization/hooks/__tests__/useBarChartStacking.test.ts

@@ -0,0 +1,313 @@
+import { renderHook } from '@testing-library/react';
+import uPlot from 'uplot';
+
+import type { UseBarChartStackingParams } from '../useBarChartStacking';
+import { useBarChartStacking } from '../useBarChartStacking';
+
+type MockConfig = { addHook: jest.Mock };
+
+function asConfig(c: MockConfig): UseBarChartStackingParams['config'] {
+	return (c as unknown) as UseBarChartStackingParams['config'];
+}
+
+function createMockConfig(): {
+	config: MockConfig;
+	invokeSetData: (plot: uPlot) => void;
+	invokeSetSeries: (
+		plot: uPlot,
+		seriesIndex: number | null,
+		opts: Partial<uPlot.Series> & { focus?: boolean },
+	) => void;
+	removeSetData: jest.Mock;
+	removeSetSeries: jest.Mock;
+} {
+	let setDataHandler: ((plot: uPlot) => void) | null = null;
+	let setSeriesHandler:
+		| ((plot: uPlot, seriesIndex: number | null, opts: uPlot.Series) => void)
+		| null = null;
+
+	const removeSetData = jest.fn();
+	const removeSetSeries = jest.fn();
+
+	const addHook = jest.fn(
+		(
+			hookName: string,
+			handler: (plot: uPlot, ...args: unknown[]) => void,
+		): (() => void) => {
+			if (hookName === 'setData') {
+				setDataHandler = handler as (plot: uPlot) => void;
+				return removeSetData;
+			}
+			if (hookName === 'setSeries') {
+				setSeriesHandler = handler as (
+					plot: uPlot,
+					seriesIndex: number | null,
+					opts: uPlot.Series,
+				) => void;
+				return removeSetSeries;
+			}
+			return jest.fn();
+		},
+	);
+
+	const config: MockConfig = { addHook };
+
+	const invokeSetData = (plot: uPlot): void => {
+		setDataHandler?.(plot);
+	};
+
+	const invokeSetSeries = (
+		plot: uPlot,
+		seriesIndex: number | null,
+		opts: Partial<uPlot.Series> & { focus?: boolean },
+	): void => {
+		setSeriesHandler?.(plot, seriesIndex, opts as uPlot.Series);
+	};
+
+	return {
+		config,
+		invokeSetData,
+		invokeSetSeries,
+		removeSetData,
+		removeSetSeries,
+	};
+}
+
+function createMockPlot(overrides: Partial<uPlot> = {}): uPlot {
+	return ({
+		data: [
+			[0, 1, 2],
+			[1, 2, 3],
+			[4, 5, 6],
+		],
+		series: [{ show: true }, { show: true }, { show: true }],
+		delBand: jest.fn(),
+		addBand: jest.fn(),
+		setData: jest.fn(),
+		...overrides,
+	} as unknown) as uPlot;
+}
+
+describe('useBarChartStacking', () => {
+	it('returns data as-is when isStackedBarChart is false', () => {
+		const data: uPlot.AlignedData = [
+			[100, 200],
+			[1, 2],
+			[3, 4],
+		];
+		const { result } = renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: false,
+				config: null,
+			}),
+		);
+		expect(result.current).toBe(data);
+	});
+
+	it('returns data as-is when config is null and isStackedBarChart is true', () => {
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+			[4, 5],
+		];
+		const { result } = renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: null,
+			}),
+		);
+		// Still returns stacked data (computed in useMemo); no hooks registered
+		expect(result.current[0]).toEqual([0, 1]);
+		expect(result.current[1]).toEqual([5, 7]); // stacked
+		expect(result.current[2]).toEqual([4, 5]);
+	});
+
+	it('returns stacked data when isStackedBarChart is true and multiple value series', () => {
+		const data: uPlot.AlignedData = [
+			[0, 1, 2],
+			[1, 2, 3],
+			[4, 5, 6],
+			[7, 8, 9],
+		];
+		const { result } = renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: null,
+			}),
+		);
+		expect(result.current[0]).toEqual([0, 1, 2]);
+		expect(result.current[1]).toEqual([12, 15, 18]); // s1+s2+s3
+		expect(result.current[2]).toEqual([11, 13, 15]); // s2+s3
+		expect(result.current[3]).toEqual([7, 8, 9]);
+	});
+
+	it('returns data as-is when only one value series (no stacking needed)', () => {
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+		];
+		const { result } = renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: null,
+			}),
+		);
+		expect(result.current).toEqual(data);
+	});
+
+	it('registers setData and setSeries hooks when isStackedBarChart and config provided', () => {
+		const { config } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+			[3, 4],
+		];
+
+		renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: asConfig(config),
+			}),
+		);
+
+		expect(config.addHook).toHaveBeenCalledWith('setData', expect.any(Function));
+		expect(config.addHook).toHaveBeenCalledWith(
+			'setSeries',
+			expect.any(Function),
+		);
+	});
+
+	it('does not register hooks when isStackedBarChart is false', () => {
+		const { config } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+			[3, 4],
+		];
+
+		renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: false,
+				config: asConfig(config),
+			}),
+		);
+
+		expect(config.addHook).not.toHaveBeenCalled();
+	});
+
+	it('calls cleanup when unmounted', () => {
+		const { config, removeSetData, removeSetSeries } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+			[3, 4],
+		];
+
+		const { unmount } = renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: asConfig(config),
+			}),
+		);
+
+		unmount();
+
+		expect(removeSetData).toHaveBeenCalled();
+		expect(removeSetSeries).toHaveBeenCalled();
+	});
+
+	it('re-stacks and updates plot when setData hook is invoked', () => {
+		const { config, invokeSetData } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1, 2],
+			[1, 2, 3],
+			[4, 5, 6],
+		];
+		const plot = createMockPlot({
+			data: [
+				[0, 1, 2],
+				[5, 7, 9],
+				[4, 5, 6],
+			],
+		});
+
+		renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: asConfig(config),
+			}),
+		);
+
+		invokeSetData(plot);
+
+		expect(plot.delBand).toHaveBeenCalledWith(null);
+		expect(plot.addBand).toHaveBeenCalled();
+		expect(plot.setData).toHaveBeenCalledWith(
+			expect.arrayContaining([
+				[0, 1, 2],
+				expect.any(Array), // stacked row 1
+				expect.any(Array), // stacked row 2
+			]),
+		);
+	});
+
+	it('re-stacks when setSeries hook is invoked (e.g. legend toggle)', () => {
+		const { config, invokeSetSeries } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[10, 20],
+			[5, 10],
+		];
+		// Plot data must match unstacked length so canApplyStacking passes
+		const plot = createMockPlot({
+			data: [
+				[0, 1],
+				[15, 30],
+				[5, 10],
+			],
+		});
+
+		renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: asConfig(config),
+			}),
+		);
+
+		invokeSetSeries(plot, 1, { show: false });
+
+		expect(plot.setData).toHaveBeenCalled();
+	});
+
+	it('does not re-stack when setSeries is called with focus option', () => {
+		const { config, invokeSetSeries } = createMockConfig();
+		const data: uPlot.AlignedData = [
+			[0, 1],
+			[1, 2],
+			[3, 4],
+		];
+		const plot = createMockPlot();
+
+		renderHook(() =>
+			useBarChartStacking({
+				data,
+				isStackedBarChart: true,
+				config: asConfig(config),
+			}),
+		);
+
+		(plot.setData as jest.Mock).mockClear();
+		invokeSetSeries(plot, 1, { focus: true } as uPlot.Series);
+
+		expect(plot.setData).not.toHaveBeenCalled();
+	});
+});

frontend/src/container/DashboardContainer/visualization/hooks/useBarChartStacking.ts

@@ -0,0 +1,125 @@
+import {
+	MutableRefObject,
+	useCallback,
+	useLayoutEffect,
+	useMemo,
+	useRef,
+} from 'react';
+import { UPlotConfigBuilder } from 'lib/uPlotV2/config/UPlotConfigBuilder';
+import { has } from 'lodash-es';
+import uPlot from 'uplot';
+
+import { stack } from '../charts/utils/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;
+}
+
+function canApplyStacking(
+	unstacked: uPlot.AlignedData | null,
+	plot: uPlot,
+	isUpdating: boolean,
+): boolean {
+	return (
+		!isUpdating &&
+		!!unstacked &&
+		!!plot.data &&
+		unstacked[0]?.length === plot.data[0]?.length
+	);
+}
+
+function setupStackingHooks(
+	config: UPlotConfigBuilder,
+	applyStackingToChart: (plot: uPlot) => void,
+	isUpdatingRef: MutableRefObject<boolean>,
+): () => void {
+	const onDataChange = (plot: uPlot): void => {
+		if (!isUpdatingRef.current) {
+			applyStackingToChart(plot);
+		}
+	};
+
+	const onSeriesVisibilityChange = (
+		plot: uPlot,
+		_seriesIdx: number | null,
+		opts: uPlot.Series,
+	): void => {
+		if (!has(opts, 'focus')) {
+			applyStackingToChart(plot);
+		}
+	};
+
+	const removeSetDataHook = config.addHook('setData', onDataChange);
+	const removeSetSeriesHook = config.addHook(
+		'setSeries',
+		onSeriesVisibilityChange,
+	);
+
+	return (): void => {
+		removeSetDataHook?.();
+		removeSetSeriesHook?.();
+	};
+}
+
+export interface UseBarChartStackingParams {
+	data: uPlot.AlignedData;
+	isStackedBarChart?: boolean;
+	config: UPlotConfigBuilder | null;
+}
+
+/**
+ * Handles stacking for bar charts: computes initial stacked data and re-stacks
+ * when data or series visibility changes (e.g. legend toggles).
+ */
+export function useBarChartStacking({
+	data,
+	isStackedBarChart = false,
+	config,
+}: UseBarChartStackingParams): uPlot.AlignedData {
+	// 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;
+		}
+		const noSeriesHidden = (): boolean => false; // include all series in initial stack
+		const { data: stacked } = stack(data, noSeriesHidden);
+		return stacked;
+	}, [data, isStackedBarChart]);
+
+	const applyStackingToChart = useCallback((plot: uPlot): void => {
+		const unstacked = unstackedDataRef.current;
+		if (
+			!unstacked ||
+			!canApplyStacking(unstacked, plot, 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;
+		}
+		return setupStackingHooks(config, applyStackingToChart, isUpdatingChartRef);
+	}, [isStackedBarChart, config, applyStackingToChart]);
+
+	return chartData;
+}

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/utils/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/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/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,
@@ -44,15 +46,10 @@ export class UPlotSeriesBuilder extends ConfigBuilder<SeriesProps, Series> {
 
 	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,
@@ -65,21 +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 };
 		}
@@ -96,7 +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);
 				},
@@ -111,21 +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,
@@ -162,44 +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 {
@@ -227,15 +203,37 @@ interface PathBuilders {
 /**
  * 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) {
 		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/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 {