[TSVB2Lens] Support top_hit of size 1 aggregation (#125766)

* [TSVB2Lens] Support top_hit of size 1 aggregation

* Add restriction to math aggregation

* Support with quick function

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

src/plugins/vis_types/timeseries/public/trigger_action/get_series.test.ts

@@ -325,6 +325,42 @@ describe('getSeries', () => {
     ]);
   });
 
+  test('should return the correct formula config for a top_hit size 1 aggregation', () => {
+    const metric = [
+      {
+        id: '12345',
+        type: 'top_hit',
+        field: 'day_of_week_i',
+        size: 1,
+        order_by: 'timestamp',
+      },
+    ] as Metric[];
+    const config = getSeries(metric);
+    expect(config).toStrictEqual([
+      {
+        agg: 'last_value',
+        fieldName: 'day_of_week_i',
+        isFullReference: false,
+        params: {
+          sortField: 'timestamp',
+        },
+      },
+    ]);
+  });
+
+  test('should return null for a top_hit size >1 aggregation', () => {
+    const metric = [
+      {
+        id: '12345',
+        type: 'top_hit',
+        field: 'day_of_week_i',
+        size: 2,
+      },
+    ] as Metric[];
+    const config = getSeries(metric);
+    expect(config).toBeNull();
+  });
+
   test('should return the correct formula for the math aggregation with percentiles as variables', () => {
     const metric = [
       {

src/plugins/vis_types/timeseries/public/trigger_action/get_series.ts

@@ -57,6 +57,15 @@ export const getSeries = (metrics: Metric[]): VisualizeEditorLayersContext['metr
           continue;
         }
         const currentMetric = metrics[layerMetricIdx];
+        // We can only support top_hit with size 1
+        if (
+          (currentMetric.type === 'top_hit' &&
+            currentMetric?.size &&
+            Number(currentMetric?.size) !== 1) ||
+          currentMetric?.order === 'asc'
+        ) {
+          return null;
+        }
 
         // should treat percentiles differently
         if (currentMetric.type === 'percentile') {
@@ -152,6 +161,29 @@ export const getSeries = (metrics: Metric[]): VisualizeEditorLayersContext['metr
       metricsArray = getFormulaSeries(formula);
       break;
     }
+    case 'top_hit': {
+      const currentMetric = metrics[metricIdx];
+      // We can only support top_hit with size 1
+      if (
+        (currentMetric?.size && Number(currentMetric?.size) !== 1) ||
+        currentMetric?.order === 'asc'
+      ) {
+        return null;
+      }
+      const timeScale = getTimeScale(currentMetric);
+      metricsArray = [
+        {
+          agg: aggregationMap.name,
+          isFullReference: aggregationMap.isFullReference,
+          fieldName: fieldName ?? 'document',
+          params: {
+            ...(timeScale && { timeScale }),
+            ...(currentMetric?.order_by && { sortField: currentMetric?.order_by }),
+          },
+        },
+      ];
+      break;
+    }
     default: {
       const timeScale = getTimeScale(metrics[metricIdx]);
       metricsArray = [

src/plugins/vis_types/timeseries/public/trigger_action/supported_metrics.ts

@@ -80,6 +80,10 @@ export const SUPPORTED_METRICS: { [key: string]: AggOptions } = {
     name: 'filter_ratio',
     isFullReference: false,
   },
+  top_hit: {
+    name: 'last_value',
+    isFullReference: false,
+  },
   math: {
     name: 'formula',
     isFullReference: true,

x-pack/plugins/lens/public/indexpattern_datasource/operations/definitions/last_value.tsx

@@ -166,6 +166,7 @@ export const lastValueOperation: OperationDefinition<LastValueIndexPatternColumn
     return errorMessages.length ? errorMessages : undefined;
   },
   buildColumn({ field, previousColumn, indexPattern }, columnParams) {
+    const lastValueParams = columnParams as LastValueIndexPatternColumn['params'];
     const sortField = isTimeFieldNameDateField(indexPattern)
       ? indexPattern.timeFieldName
       : indexPattern.fields.find((f) => f.type === 'date')?.name;
@@ -188,7 +189,7 @@ export const lastValueOperation: OperationDefinition<LastValueIndexPatternColumn
       filter: getFilter(previousColumn, columnParams),
       timeShift: columnParams?.shift || previousColumn?.timeShift,
       params: {
-        sortField,
+        sortField: lastValueParams?.sortField || sortField,
         ...getFormatFromPreviousColumn(previousColumn),
       },
     };