[Lens] Provide single-value functions to show the "Last" value of some field

x-pack/plugins/lens/public/indexpattern_datasource/dimension_panel/dimension_editor.scss

@@ -15,6 +15,10 @@
   column-gap: $euiSizeXL;
 }
 
+.lnsIndexPatternDimensionEditor__operation .euiListGroupItem__label {
+  width: 100%;
+}
+
 .lnsIndexPatternDimensionEditor__operation > button {
   padding-top: 0;
   padding-bottom: 0;

x-pack/plugins/lens/public/indexpattern_datasource/dimension_panel/dimension_editor.tsx

@@ -15,6 +15,10 @@ import {
   EuiSpacer,
   EuiListGroupItemProps,
   EuiFormLabel,
+  EuiFlexGroup,
+  EuiFlexItem,
+  EuiToolTip,
+  EuiIcon,
 } from '@elastic/eui';
 import { IndexPatternDimensionEditorProps } from './dimension_panel';
 import { OperationSupportMatrix } from './operation_support';
@@ -122,6 +126,9 @@ export function DimensionEditor(props: DimensionEditorProps) {
           definition.input === 'field' &&
           fieldByOperation[operationType]?.has(selectedColumn.sourceField)) ||
         (selectedColumn && !hasField(selectedColumn) && definition.input !== 'field'),
+      disabledStatus:
+        definition.getDisabledStatus &&
+        definition.getDisabledStatus(state.indexPatterns[state.currentIndexPatternId]),
     };
   });
 
@@ -135,7 +142,7 @@ export function DimensionEditor(props: DimensionEditorProps) {
   );
 
   const sideNavItems: EuiListGroupItemProps[] = operationsWithCompatibility.map(
-    ({ operationType, compatibleWithCurrentField }) => {
+    ({ operationType, compatibleWithCurrentField, disabledStatus }) => {
       const isActive = Boolean(
         incompatibleSelectedOperationType === operationType ||
           (!incompatibleSelectedOperationType &&
@@ -151,7 +158,18 @@ export function DimensionEditor(props: DimensionEditorProps) {
       }
 
       let label: EuiListGroupItemProps['label'] = operationPanels[operationType].displayName;
-      if (isActive) {
+      if (disabledStatus) {
+        label = (
+          <EuiFlexGroup justifyContent="spaceBetween">
+            <EuiFlexItem>{operationPanels[operationType].displayName}</EuiFlexItem>
+            <EuiFlexItem grow={false}>
+              <EuiToolTip position="top" content={disabledStatus}>
+                <EuiIcon type="questionInCircle" size="m" />
+              </EuiToolTip>
+            </EuiFlexItem>
+          </EuiFlexGroup>
+        );
+      } else if (isActive) {
         label = <strong>{operationPanels[operationType].displayName}</strong>;
       }
 
@@ -161,6 +179,7 @@ export function DimensionEditor(props: DimensionEditorProps) {
         color,
         isActive,
         size: 's',
+        isDisabled: !!disabledStatus,
         className: 'lnsIndexPatternDimensionEditor__operation',
         'data-test-subj': `lns-indexPatternDimension-${operationType}${
           compatibleWithCurrentField ? '' : ' incompatible'
@@ -220,7 +239,6 @@ export function DimensionEditor(props: DimensionEditorProps) {
               ? currentIndexPattern.getFieldByName(selectedColumn.sourceField)
               : undefined,
           });
-
           setState(mergeLayer({ state, layerId, newLayer }));
         },
       };

x-pack/plugins/lens/public/indexpattern_datasource/dimension_panel/dimension_panel.test.tsx

@@ -975,12 +975,12 @@ describe('IndexPatternDimensionEditorPanel', () => {
     expect(items.map(({ label }: { label: React.ReactNode }) => label)).toEqual([
       'Average',
       'Count',
+      'Last value',
       'Maximum',
       'Median',
       'Minimum',
       'Sum',
       'Unique count',
-      '\u00a0',
     ]);
   });
 

x-pack/plugins/lens/public/indexpattern_datasource/operations/definitions/index.ts

@@ -23,6 +23,7 @@ import {
 } from './metrics';
 import { dateHistogramOperation, DateHistogramIndexPatternColumn } from './date_histogram';
 import { countOperation, CountIndexPatternColumn } from './count';
+import { lastValueOperation, LastValueIndexPatternColumn } from './last_value';
 import { StateSetter, OperationMetadata } from '../../../types';
 import { BaseIndexPatternColumn } from './column_types';
 import { IndexPatternPrivateState, IndexPattern, IndexPatternField } from '../../types';
@@ -46,7 +47,8 @@ export type IndexPatternColumn =
   | CardinalityIndexPatternColumn
   | SumIndexPatternColumn
   | MedianIndexPatternColumn
-  | CountIndexPatternColumn;
+  | CountIndexPatternColumn
+  | LastValueIndexPatternColumn;
 
 export type FieldBasedIndexPatternColumn = Extract<IndexPatternColumn, { sourceField: string }>;
 
@@ -63,6 +65,7 @@ const internalOperationDefinitions = [
   cardinalityOperation,
   sumOperation,
   medianOperation,
+  lastValueOperation,
   countOperation,
   rangeOperation,
 ];
@@ -73,6 +76,7 @@ export { filtersOperation } from './filters';
 export { dateHistogramOperation } from './date_histogram';
 export { minOperation, averageOperation, sumOperation, maxOperation } from './metrics';
 export { countOperation } from './count';
+export { lastValueOperation } from './last_value';
 
 /**
  * Properties passed to the operation-specific part of the popover editor
@@ -135,6 +139,12 @@ interface BaseOperationDefinitionProps<C extends BaseIndexPatternColumn> {
    * present on the new index pattern.
    */
   transfer?: (column: C, newIndexPattern: IndexPattern) => C;
+  /**
+   * if there is some reason to display the operation in the operations list
+   * but disable it from usage, this function returns the string describing
+   * the status. Otherwise it returns undefined
+   */
+  getDisabledStatus?: (indexPattern: IndexPattern) => string | undefined;
 }
 
 interface BaseBuildColumnArgs {