[ML] Fix Single Metric Viewer not showing chart for metric functions and mismatch function in tooltip (#176354)

## Summary

This PR fixes https://github.com/elastic/kibana/issues/176301. Fixes
include:

1) The schema for `getAnomalyRecordsSchema` was updated, but missed the
additional parameter `functionDescription `. So the API call was
throwing error.
2) The tooltip to showcase the underlying function (min, max, or avg)
for metric detector that yields the highest anomaly score was showing
the incorrect fallback value.
3) Fix label in Single Metric Viewer to match with the min/max/avg used:


After


03d8e10b-c4cd-4c28-a28c-7c6a7e108065

<img width="1728" alt="Screenshot 2024-02-06 at 17 11 15"
src="47d6eae6-758b-4514-a3d6-a29bc866d1d2">





### Checklist

Delete any items that are not applicable to this PR.

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)


### Risk Matrix

Delete this section if it is not applicable to this PR.

Before closing this PR, invite QA, stakeholders, and other developers to
identify risks that should be tested prior to the change/feature
release.

When forming the risk matrix, consider some of the following examples
and how they may potentially impact the change:

| Risk | Probability | Severity | Mitigation/Notes |

|---------------------------|-------------|----------|-------------------------|
| Multiple Spaces&mdash;unexpected behavior in non-default Kibana Space.
| Low | High | Integration tests will verify that all features are still
supported in non-default Kibana Space and when user switches between
spaces. |
| Multiple nodes&mdash;Elasticsearch polling might have race conditions
when multiple Kibana nodes are polling for the same tasks. | High | Low
| Tasks are idempotent, so executing them multiple times will not result
in logical error, but will degrade performance. To test for this case we
add plenty of unit tests around this logic and document manual testing
procedure. |
| Code should gracefully handle cases when feature X or plugin Y are
disabled. | Medium | High | Unit tests will verify that any feature flag
or plugin combination still results in our service operational. |
| [See more potential risk
examples](https://github.com/elastic/kibana/blob/main/RISK_MATRIX.mdx) |


### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/ml/public/application/timeseriesexplorer/timeseries_search_service.ts

@@ -6,6 +6,7 @@
  */
 
 import { each, find, get, filter } from 'lodash';
+import type { ES_AGGREGATION } from '@kbn/ml-anomaly-utils';
 
 import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
@@ -15,7 +16,6 @@ import {
   isModelPlotChartableForDetector,
   isModelPlotEnabled,
 } from '../../../common/util/job_utils';
-// @ts-ignore
 import { buildConfigFromDetector } from '../util/chart_config_builder';
 import { mlResultsService } from '../services/results_service';
 import { ModelPlotOutput } from '../services/results_service/result_service_rx';
@@ -113,29 +113,48 @@ function getMetricData(
   }
 }
 
-// Builds chart detail information (charting function description and entity counts) used
-// in the title area of the time series chart.
-// Queries Elasticsearch if necessary to obtain the distinct count of entities
-// for which data is being plotted.
+interface TimeSeriesExplorerChartDetails {
+  success: boolean;
+  results: {
+    functionLabel: string | null;
+    entityData: { count?: number; entities: Array<{ fieldName: string; cardinality?: number }> };
+  };
+}
+
+/**
+ * Builds chart detail information (charting function description and entity counts) used
+ * in the title area of the time series chart.
+ * Queries Elasticsearch if necessary to obtain the distinct count of entities
+ * for which data is being plotted.
+ * @param job Job config info
+ * @param detectorIndex The index of the detector in the job config
+ * @param entityFields Array of field name - field value pairs
+ * @param earliestMs Earliest timestamp in milliseconds
+ * @param latestMs Latest timestamp in milliseconds
+ * @param metricFunctionDescription The underlying function (min, max, avg) for "metric" detector type
+ * @returns chart data to plot for Single Metric Viewer/Time series explorer
+ */
 function getChartDetails(
   job: Job,
   detectorIndex: number,
-  entityFields: any[],
+  entityFields: MlEntityField[],
   earliestMs: number,
-  latestMs: number
+  latestMs: number,
+  metricFunctionDescription?: ES_AGGREGATION
 ) {
   return new Promise((resolve, reject) => {
-    const obj: any = {
+    const obj: TimeSeriesExplorerChartDetails = {
       success: true,
       results: { functionLabel: '', entityData: { entities: [] } },
     };
 
-    const chartConfig = buildConfigFromDetector(job, detectorIndex);
+    const chartConfig = buildConfigFromDetector(job, detectorIndex, metricFunctionDescription);
+
     let functionLabel: string | null = chartConfig.metricFunction;
     if (chartConfig.metricFieldName !== undefined) {
-      functionLabel += ' ';
-      functionLabel += chartConfig.metricFieldName;
+      functionLabel += ` ${chartConfig.metricFieldName}`;
     }
+
     obj.results.functionLabel = functionLabel;
 
     const blankEntityFields = filter(entityFields, (entity) => {

x-pack/plugins/ml/public/application/timeseriesexplorer/timeseriesexplorer.js

@@ -568,7 +568,8 @@ export class TimeSeriesExplorer extends React.Component {
             detectorIndex,
             entityControls,
             searchBounds.min.valueOf(),
-            searchBounds.max.valueOf()
+            searchBounds.max.valueOf(),
+            this.props.functionDescription
           )
           .then((resp) => {
             stateUpdate.chartDetails = resp.results;

x-pack/plugins/ml/public/application/util/chart_config_builder.ts

@@ -19,9 +19,19 @@ import { Job } from '../../../common/types/anomaly_detection_jobs';
 
 import { mlFunctionToESAggregation } from '../../../common/util/job_utils';
 
-// Builds the basic configuration to plot a chart of the source data
-// analyzed by the the detector at the given index from the specified ML job.
-export function buildConfigFromDetector(job: Job, detectorIndex: number) {
+/**
+ * Builds the basic configuration to plot a chart of the source data
+ * analyzed by the the detector at the given index from the specified ML job.
+ * @param job Job config info
+ * @param detectorIndex The index of the detector in the job config
+ * @param metricFunctionDescription The underlying function (min, max, avg) for "metric" detector type
+ * @returns
+ */
+export function buildConfigFromDetector(
+  job: Job,
+  detectorIndex: number,
+  metricFunctionDescription?: ES_AGGREGATION
+) {
   const analysisConfig = job.analysis_config;
   const detector = analysisConfig.detectors[detectorIndex];
 
@@ -38,6 +48,9 @@ export function buildConfigFromDetector(job: Job, detectorIndex: number) {
     datafeedConfig: job.datafeed_config!,
     summaryCountFieldName: job.analysis_config.summary_count_field_name,
   };
+  if (detector.function === ML_JOB_AGGREGATION.METRIC && metricFunctionDescription !== undefined) {
+    config.metricFunction = metricFunctionDescription;
+  }
 
   if (detector.field_name !== undefined) {
     config.metricFieldName = detector.field_name;

x-pack/plugins/ml/server/models/results_service/anomaly_charts.ts

@@ -766,12 +766,12 @@ export function anomalyChartsDataProvider(mlClient: MlClient, client: IScopedClu
     }
 
     // Build the tooltip data for the chart info icon, showing further details on what is being plotted.
-    let functionLabel = `${config.metricFunction}`;
+    let functionLabel = `${fullSeriesConfig.metricFunction ?? config.metricFunction}`;
     if (
       fullSeriesConfig.metricFieldName !== undefined &&
       fullSeriesConfig.metricFieldName !== null
     ) {
-      functionLabel += ` ${fullSeriesConfig.metricFieldName}`;
+      functionLabel += `(${fullSeriesConfig.metricFieldName})`;
     }
 
     fullSeriesConfig.infoTooltip = {

x-pack/plugins/ml/server/routes/schemas/results_service_schema.ts

@@ -144,4 +144,5 @@ export const getAnomalyRecordsSchema = schema.object({
   latestMs: schema.number(),
   criteriaFields: schema.arrayOf(schema.any()),
   interval: schema.string(),
+  functionDescription: schema.maybe(schema.nullable(schema.string())),
 });