sentry/static/app/views/ddm/chart/chart.tsx

import {forwardRef, useEffect, useMemo, useRef} from 'react';
import styled from '@emotion/styled';
import Color from 'color';
import * as echarts from 'echarts/core';
import {CanvasRenderer} from 'echarts/renderers';
import isNil from 'lodash/isNil';
import omitBy from 'lodash/omitBy';

import {transformToAreaSeries} from 'sentry/components/charts/areaChart';
import {transformToBarSeries} from 'sentry/components/charts/barChart';
import BaseChart from 'sentry/components/charts/baseChart';
import {
  defaultFormatAxisLabel,
  getFormatter,
} from 'sentry/components/charts/components/tooltip';
import {transformToLineSeries} from 'sentry/components/charts/lineChart';
import ScatterSeries from 'sentry/components/charts/series/scatterSeries';
import {isChartHovered} from 'sentry/components/charts/utils';
import {t} from 'sentry/locale';
import type {ReactEchartsRef} from 'sentry/types/echarts';
import mergeRefs from 'sentry/utils/mergeRefs';
import {formatMetricUsingUnit} from 'sentry/utils/metrics/formatters';
import {MetricDisplayType} from 'sentry/utils/metrics/types';
import usePageFilters from 'sentry/utils/usePageFilters';
import type {CombinedMetricChartProps, Series} from 'sentry/views/ddm/chart/types';
import type {UseFocusAreaResult} from 'sentry/views/ddm/chart/useFocusArea';
import type {UseMetricSamplesResult} from 'sentry/views/ddm/chart/useMetricChartSamples';

const MAIN_X_AXIS_ID = 'xAxis';

type ChartProps = {
  displayType: MetricDisplayType;
  series: Series[];
  focusArea?: UseFocusAreaResult;
  group?: string;
  height?: number;
  samples?: UseMetricSamplesResult;
};

// We need to enable canvas renderer for echarts before we use it here.
// Once we use it in more places, this should probably move to a more global place
// But for now we keep it here to not invluence the bundle size of the main chunks.
echarts.use(CanvasRenderer);

function isNonZeroValue(value: number | null) {
  return value !== null && value !== 0;
}

function addSeriesPadding(data: Series['data']) {
  const hasNonZeroSibling = (index: number) => {
    return (
      isNonZeroValue(data[index - 1]?.value) || isNonZeroValue(data[index + 1]?.value)
    );
  };
  const paddingIndices = new Set<number>();
  return {
    data: data.map(({name, value}, index) => {
      const shouldAddPadding = value === null && hasNonZeroSibling(index);
      if (shouldAddPadding) {
        paddingIndices.add(index);
      }
      return {
        name,
        value: shouldAddPadding ? 0 : value,
      };
    }),
    paddingIndices,
  };
}

export const MetricChart = forwardRef<ReactEchartsRef, ChartProps>(
  ({series, displayType, height, group, samples, focusArea}, forwardedRef) => {
    const chartRef = useRef<ReactEchartsRef>(null);

    const filteredSeries = useMemo(() => series.filter(s => !s.hidden), [series]);

    const firstUnit = filteredSeries[0]?.unit || 'none';
    const uniqueUnits = useMemo(
      () => [...new Set(filteredSeries.map(s => s.unit || 'none'))],
      [filteredSeries]
    );

    useEffect(() => {
      if (!group) {
        return;
      }
      const echartsInstance = chartRef?.current?.getEchartsInstance();
      if (echartsInstance && !echartsInstance.group) {
        echartsInstance.group = group;
      }
    });

    // TODO(ddm): This assumes that all series have the same bucket size
    const bucketSize = series[0]?.data[1]?.name - series[0]?.data[0]?.name;
    const isSubMinuteBucket = bucketSize < 60_000;
    const lastBucketTimestamp = series[0]?.data?.[series[0]?.data?.length - 1]?.name;
    const ingestionBuckets = useMemo(
      () => getIngestionDelayBucketCount(bucketSize, lastBucketTimestamp),
      [bucketSize, lastBucketTimestamp]
    );

    const seriesToShow = useMemo(
      () =>
        filteredSeries
          .map(s => {
            const mappedSeries = {
              ...s,
              silent: true,
              yAxisIndex: uniqueUnits.indexOf(s.unit),
              xAxisIndex: 0,
              ...(displayType !== MetricDisplayType.BAR
                ? addSeriesPadding(s.data)
                : {data: s.data}),
            };
            if (displayType === MetricDisplayType.BAR) {
              mappedSeries.stack = s.unit;
            }
            return mappedSeries;
          })
          // Split series in two parts, one for the main chart and one for the fog of war
          // The order is important as the tooltip will show the first series first (for overlaps)
          .flatMap(s => createIngestionSeries(s, ingestionBuckets, displayType)),
      [filteredSeries, uniqueUnits, displayType, ingestionBuckets]
    );

    const {selection} = usePageFilters();

    const dateTimeOptions = useMemo(() => {
      return omitBy(selection.datetime, isNil);
    }, [selection.datetime]);

    const chartProps = useMemo(() => {
      const seriesUnits = seriesToShow.reduce(
        (acc, s) => {
          acc[s.seriesName] = s.unit;
          return acc;
        },
        {} as Record<string, string>
      );

      const timeseriesFormatters = {
        valueFormatter: (value: number, seriesName?: string) => {
          const unit = (seriesName && seriesUnits[seriesName]) ?? 'none';
          return formatMetricUsingUnit(value, unit);
        },
        isGroupedByDate: true,
        bucketSize,
        showTimeInTooltip: true,
        addSecondsToTimeFormat: isSubMinuteBucket,
        limit: 10,
        filter: (_, seriesParam) => {
          return seriesParam?.axisId === MAIN_X_AXIS_ID;
        },
      };

      const heightOptions = height ? {height} : {autoHeightResize: true};

      let baseChartProps: CombinedMetricChartProps = {
        ...heightOptions,
        ...dateTimeOptions,
        displayType,
        forwardedRef: mergeRefs([forwardedRef, chartRef]),
        series: seriesToShow,
        devicePixelRatio: 2,
        renderer: 'canvas' as const,
        isGroupedByDate: true,
        colors: seriesToShow.map(s => s.color),
        grid: {
          top: 5,
          bottom: 0,
          left: 0,
          right: 0,
        },
        tooltip: {
          formatter: (params, asyncTicket) => {
            // Only show the tooltip if the current chart is hovered
            // as chart groups trigger the tooltip for all charts in the group when one is hoverered
            if (!isChartHovered(chartRef?.current)) {
              return '';
            }

            // The mechanism by which we display ingestion delay the chart, duplicates the series in the chart data
            // so we need to de-duplicate the series before showing the tooltip
            // this assumes that the first series is the main series and the second is the ingestion delay series
            if (Array.isArray(params)) {
              const uniqueSeries = new Set<string>();
              const deDupedParams = params.filter(param => {
                // Filter null values from tooltip
                if (param.value[1] === null) {
                  return false;
                }

                // scatter series (samples) have their own tooltip
                if (param.seriesType === 'scatter') {
                  return false;
                }

                // Filter padding datapoints from tooltip
                if (param.value[1] === 0) {
                  const currentSeries = seriesToShow[param.seriesIndex];
                  const paddingIndices =
                    'paddingIndices' in currentSeries
                      ? currentSeries.paddingIndices
                      : undefined;
                  if (paddingIndices?.has(param.dataIndex)) {
                    return false;
                  }
                }

                if (uniqueSeries.has(param.seriesName)) {
                  return false;
                }
                uniqueSeries.add(param.seriesName);
                return true;
              });

              const date = defaultFormatAxisLabel(
                params[0].value[0] as number,
                timeseriesFormatters.isGroupedByDate,
                false,
                timeseriesFormatters.showTimeInTooltip,
                timeseriesFormatters.addSecondsToTimeFormat,
                timeseriesFormatters.bucketSize
              );

              if (deDupedParams.length === 0) {
                return [
                  '<div class="tooltip-series">',
                  `<center>${t('No data available')}</center>`,
                  '</div>',
                  `<div class="tooltip-footer">${date}</div>`,
                ].join('');
              }
              return getFormatter(timeseriesFormatters)(deDupedParams, asyncTicket);
            }
            return getFormatter(timeseriesFormatters)(params, asyncTicket);
          },
        },
        yAxes:
          uniqueUnits.length === 0
            ? // fallback axis for when there are no series as echarts requires at least one axis
              [
                {
                  id: 'none',
                  axisLabel: {
                    formatter: (value: number) => {
                      return formatMetricUsingUnit(value, 'none');
                    },
                  },
                },
              ]
            : [
                ...uniqueUnits.map((unit, index) =>
                  unit === firstUnit
                    ? {
                        id: unit,
                        axisLabel: {
                          formatter: (value: number) => {
                            return formatMetricUsingUnit(value, unit);
                          },
                        },
                      }
                    : {
                        id: unit,
                        show: index === 1,
                        axisLabel: {
                          show: index === 1,
                          formatter: (value: number) => {
                            return formatMetricUsingUnit(value, unit);
                          },
                        },
                        splitLine: {
                          show: false,
                        },
                        position: 'right' as const,
                        axisPointer: {
                          type: 'none' as const,
                        },
                      }
                ),
              ],
        xAxes: [
          {
            id: MAIN_X_AXIS_ID,
            axisPointer: {
              snap: true,
            },
          },
        ],
      };

      if (samples?.applyChartProps) {
        baseChartProps = samples.applyChartProps(baseChartProps);
      }
      // Apply focus area props as last so it can disable tooltips
      if (focusArea?.applyChartProps) {
        baseChartProps = focusArea.applyChartProps(baseChartProps);
      }

      return baseChartProps;
    }, [
      seriesToShow,
      dateTimeOptions,
      bucketSize,
      isSubMinuteBucket,
      height,
      displayType,
      forwardedRef,
      uniqueUnits,
      samples,
      focusArea,
      firstUnit,
    ]);

    return (
      <ChartWrapper>
        {focusArea?.overlay}
        <CombinedChart {...chartProps} />
      </ChartWrapper>
    );
  }
);

function CombinedChart({
  displayType,
  series,
  scatterSeries = [],
  ...chartProps
}: CombinedMetricChartProps) {
  const combinedSeries = useMemo(() => {
    if (displayType === MetricDisplayType.LINE) {
      return [
        ...transformToLineSeries({series}),
        ...transformToScatterSeries({series: scatterSeries, displayType}),
      ];
    }

    if (displayType === MetricDisplayType.BAR) {
      return [
        ...transformToBarSeries({series, stacked: true, animation: false}),
        ...transformToScatterSeries({series: scatterSeries, displayType}),
      ];
    }

    if (displayType === MetricDisplayType.AREA) {
      return [
        ...transformToAreaSeries({series, stacked: true, colors: chartProps.colors}),
        ...transformToScatterSeries({series: scatterSeries, displayType}),
      ];
    }

    return [];
  }, [displayType, scatterSeries, series, chartProps.colors]);

  return <BaseChart {...chartProps} series={combinedSeries} />;
}

function transformToScatterSeries({
  series,
  displayType,
}: {
  displayType: MetricDisplayType;
  series: Series[];
}) {
  return series.map(({seriesName, data: seriesData, ...options}) => {
    if (displayType === MetricDisplayType.BAR) {
      return ScatterSeries({
        ...options,
        name: seriesName,
        data: seriesData?.map(({value, name}) => ({value: [name, value]})),
      });
    }

    return ScatterSeries({
      ...options,
      name: seriesName,
      data: seriesData?.map(({value, name}) => [name, value]),
      animation: false,
    });
  });
}

function createIngestionSeries(
  orignalSeries: Series,
  ingestionBuckets: number,
  displayType: MetricDisplayType
) {
  if (ingestionBuckets < 1) {
    return [orignalSeries];
  }

  const series = [
    {
      ...orignalSeries,
      data: orignalSeries.data.slice(0, -ingestionBuckets),
    },
  ];

  if (displayType === MetricDisplayType.BAR) {
    series.push(createIngestionBarSeries(orignalSeries, ingestionBuckets));
  } else if (displayType === MetricDisplayType.AREA) {
    series.push(createIngestionAreaSeries(orignalSeries, ingestionBuckets));
  } else {
    series.push(createIngestionLineSeries(orignalSeries, ingestionBuckets));
  }

  return series;
}

const EXTRAPOLATED_AREA_STRIPE_IMG =
  'image://data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAABkCAYAAAC/zKGXAAAAMUlEQVR4Ae3KoREAIAwEsMKgrMeYj8BzyIpEZyTZda16mPVJFEVRFEVRFEVRFMWO8QB4uATKpuU51gAAAABJRU5ErkJggg==';

export const getIngestionSeriesId = (seriesId: string) => `${seriesId}-ingestion`;

function createIngestionBarSeries(series: Series, fogBucketCnt = 0) {
  return {
    ...series,
    id: getIngestionSeriesId(series.id),
    silent: true,
    data: series.data.map((data, index) => ({
      ...data,
      // W need to set a value for the non-fog of war buckets so that the stacking still works in echarts
      value: index < series.data.length - fogBucketCnt ? 0 : data.value,
    })),
    itemStyle: {
      opacity: 1,
      decal: {
        symbol: EXTRAPOLATED_AREA_STRIPE_IMG,
        dashArrayX: [6, 0],
        dashArrayY: [6, 0],
        rotation: Math.PI / 4,
      },
    },
  };
}

function createIngestionLineSeries(series: Series, fogBucketCnt = 0) {
  return {
    ...series,
    id: getIngestionSeriesId(series.id),
    silent: true,
    // We include the last non-fog of war bucket so that the line is connected
    data: series.data.slice(-fogBucketCnt - 1),
    lineStyle: {
      type: 'dotted',
    },
  };
}

function createIngestionAreaSeries(series: Series, fogBucketCnt = 0) {
  return {
    ...series,
    id: getIngestionSeriesId(series.id),
    silent: true,
    stack: 'fogOfWar',
    // We include the last non-fog of war bucket so that the line is connected
    data: series.data.slice(-fogBucketCnt - 1),
    lineStyle: {
      type: 'dotted',
      color: Color(series.color).lighten(0.3).string(),
    },
  };
}

const AVERAGE_INGESTION_DELAY_MS = 90_000;
/**
 * Calculates the number of buckets, affected by ingestion delay.
 * Based on the AVERAGE_INGESTION_DELAY_MS
 * @param bucketSize in ms
 * @param lastBucketTimestamp starting time of the last bucket in ms
 */
function getIngestionDelayBucketCount(bucketSize: number, lastBucketTimestamp: number) {
  const timeSinceLastBucket = Date.now() - (lastBucketTimestamp + bucketSize);
  const ingestionAffectedTime = Math.max(
    0,
    AVERAGE_INGESTION_DELAY_MS - timeSinceLastBucket
  );

  return Math.ceil(ingestionAffectedTime / bucketSize);
}

const ChartWrapper = styled('div')`
  position: relative;
  height: 100%;
`;