sentry/static/app/views/monitors/utils/mergeBuckets.tsx

import {
  JobTickData,
  MonitorBucketData,
} from 'sentry/views/monitors/components/overviewTimeline/types';

import {filterMonitorStatsBucketByEnv} from './filterMonitorStatsBucketByEnv';
import {getAggregateStatus} from './getAggregateStatus';
import {getAggregateStatusFromMultipleBuckets} from './getAggregateStatusFromMultipleBuckets';
import {isEnvMappingEmpty} from './isEnvMappingEmpty';
import {mergeEnvMappings} from './mergeEnvMappings';

function generateJobTickFromBucket(
  bucket: MonitorBucketData[number],
  options?: Partial<JobTickData>
) {
  const [timestamp, envMapping] = bucket;
  return {
    endTs: timestamp,
    startTs: timestamp,
    width: 1,
    envMapping,
    roundedLeft: false,
    roundedRight: false,
    ...options,
  };
}

export function mergeBuckets(data: MonitorBucketData, environment: string) {
  const minTickWidth = 4;

  const jobTicks: JobTickData[] = [];
  data.reduce((currentJobTick, bucket, i) => {
    const filteredBucket = filterMonitorStatsBucketByEnv(bucket, environment);

    const [timestamp, envMapping] = filteredBucket;
    const envMappingEmpty = isEnvMappingEmpty(envMapping);
    if (!currentJobTick) {
      return envMappingEmpty
        ? currentJobTick
        : generateJobTickFromBucket(filteredBucket, {roundedLeft: true});
    }
    const bucketStatus = getAggregateStatus(envMapping);
    const currJobTickStatus = getAggregateStatus(currentJobTick.envMapping);
    // If the current bucket is empty and our job tick has reached a min width
    if (envMappingEmpty && currentJobTick.width >= minTickWidth) {
      // Then add our current tick to the running list of job ticks to render
      currentJobTick.roundedRight = true;
      jobTicks.push(currentJobTick);

      return null;
    }

    const nextTickAggregateStatus = getAggregateStatusFromMultipleBuckets(
      data.slice(i, i + minTickWidth).map(([_, envData]) => envData)
    );
    // If the next buckets have a different status from our current job tick
    if (
      bucketStatus !== currJobTickStatus &&
      nextTickAggregateStatus !== currJobTickStatus &&
      currentJobTick.width >= minTickWidth
    ) {
      // Then add our current tick to the running list of job ticks to render
      jobTicks.push(currentJobTick);
      return generateJobTickFromBucket(filteredBucket);
    }

    // Merge our current tick with the current bucket data
    currentJobTick = {
      ...currentJobTick,
      endTs: timestamp,
      envMapping: mergeEnvMappings(currentJobTick.envMapping, envMapping),
      width: currentJobTick.width + 1,
    };

    // Ensure we render the last tick
    if (i === data.length - 1) {
      currentJobTick.roundedRight = true;
      jobTicks.push(currentJobTick);
    }
    return currentJobTick;
  }, null as JobTickData | null);

  return jobTicks;
}