[ES|QL] Sets the KQL/Lucene query on dataview to ES|QL transition (#206391)

## Summary

Closes https://github.com/elastic/kibana/issues/203368

Transitions the KQL / Lucene query while transitioning from dataview to
ES|QL mode


![meow](https://github.com/user-attachments/assets/f0572699-c515-4348-8cee-35fdb6545fa4)


### Checklist
- [ ] [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

src/platform/packages/shared/kbn-esql-utils/src/utils/get_initial_esql_query.test.ts

@@ -101,4 +101,79 @@ describe('getInitialESQLQuery', () => {
       'FROM logs* | WHERE @custom_timestamp >= ?_tstart AND @custom_timestamp <= ?_tend | LIMIT 10'
     );
   });
+
+  it('should append a where clause correctly if there is no @timestamp in the index fields and a query is given', () => {
+    const fields = [
+      {
+        name: '@custom_timestamp',
+        displayName: '@custom_timestamp',
+        type: 'date',
+        scripted: false,
+        filterable: true,
+        aggregatable: true,
+        sortable: true,
+      },
+      {
+        name: 'message',
+        displayName: 'message',
+        type: 'string',
+        scripted: false,
+        filterable: false,
+      },
+    ] as DataView['fields'];
+    const dataView = getDataView('logs*', fields, '@custom_timestamp');
+    expect(getInitialESQLQuery(dataView, { language: 'kuery', query: 'error' })).toBe(
+      'FROM logs* | WHERE @custom_timestamp >= ?_tstart AND @custom_timestamp <= ?_tend AND KQL("""error""") | LIMIT 10'
+    );
+  });
+
+  it('should append a where clause correctly if there is @timestamp in the index fields and a query is given', () => {
+    const fields = [
+      {
+        name: '@timestamp',
+        displayName: '@timestamp',
+        type: 'date',
+        scripted: false,
+        filterable: true,
+        aggregatable: true,
+        sortable: true,
+      },
+      {
+        name: 'message',
+        displayName: 'message',
+        type: 'string',
+        scripted: false,
+        filterable: false,
+      },
+    ] as DataView['fields'];
+    const dataView = getDataView('logs*', fields, 'timestamp');
+    expect(getInitialESQLQuery(dataView, { language: 'lucene', query: 'error' })).toBe(
+      'FROM logs* | WHERE QSTR("""error""") | LIMIT 10'
+    );
+  });
+
+  it('should not append a where clause correctly if there is @timestamp in the index fields and no kql or lucene query is given', () => {
+    const fields = [
+      {
+        name: '@timestamp',
+        displayName: '@timestamp',
+        type: 'date',
+        scripted: false,
+        filterable: true,
+        aggregatable: true,
+        sortable: true,
+      },
+      {
+        name: 'message',
+        displayName: 'message',
+        type: 'string',
+        scripted: false,
+        filterable: false,
+      },
+    ] as DataView['fields'];
+    const dataView = getDataView('logs*', fields, 'timestamp');
+    expect(getInitialESQLQuery(dataView, { language: 'unknown', query: 'error' })).toBe(
+      'FROM logs* | LIMIT 10'
+    );
+  });
 });

src/platform/packages/shared/kbn-esql-utils/src/utils/get_initial_esql_query.ts

@@ -8,6 +8,31 @@
  */
 
 import type { DataView } from '@kbn/data-views-plugin/public';
+import { type Query, escapeQuotes } from '@kbn/es-query';
+
+const getFilterBySearchText = (query?: Query) => {
+  if (!query) {
+    return '';
+  }
+  const searchTextFunc =
+    query.language === 'kuery' ? 'KQL' : query.language === 'lucene' ? 'QSTR' : '';
+
+  if (searchTextFunc && query.query) {
+    const escapedQuery =
+      typeof query.query === 'string' && query.language === 'lucene'
+        ? escapeQuotes(query.query)
+        : query.query;
+    return `${searchTextFunc}("""${escapedQuery}""")`;
+  }
+  return '';
+};
+
+const getFinalWhereClause = (timeFilter?: string, queryFilter?: string) => {
+  if (timeFilter && queryFilter) {
+    return ` | WHERE ${timeFilter} AND ${queryFilter}`;
+  }
+  return timeFilter || queryFilter ? ` | WHERE ${timeFilter || queryFilter}` : '';
+};
 
 /**
  * Builds an ES|QL query for the provided dataView
@@ -15,12 +40,16 @@ import type { DataView } from '@kbn/data-views-plugin/public';
  * If there is no @timestamp and there is a dataView timeFieldName, we add the WHERE clause with the timeFieldName
  * @param dataView
  */
-export function getInitialESQLQuery(dataView: DataView): string {
+export function getInitialESQLQuery(dataView: DataView, query?: Query): string {
   const hasAtTimestampField = dataView?.fields?.getByName?.('@timestamp')?.type === 'date';
   const timeFieldName = dataView?.timeFieldName;
   const filterByTimeParams =
     !hasAtTimestampField && timeFieldName
-      ? ` | WHERE ${timeFieldName} >= ?_tstart AND ${timeFieldName} <= ?_tend`
+      ? `${timeFieldName} >= ?_tstart AND ${timeFieldName} <= ?_tend`
       : '';
-  return `FROM ${dataView.getIndexPattern()}${filterByTimeParams} | LIMIT 10`;
+
+  const filterBySearchText = getFilterBySearchText(query);
+
+  const whereClause = getFinalWhereClause(filterByTimeParams, filterBySearchText);
+  return `FROM ${dataView.getIndexPattern()}${whereClause} | LIMIT 10`;
 }

src/platform/plugins/shared/discover/public/application/main/state_management/discover_state.test.ts

@@ -774,9 +774,10 @@ describe('Test discover state actions', () => {
     savedSearchWithQuery.searchSource.setField('filter', filters);
     const { state } = await getState('/', { savedSearch: savedSearchWithQuery });
     state.globalState?.set({ filters });
+    state.appState.set({ query });
     await state.actions.transitionFromDataViewToESQL(dataViewMock);
     expect(state.appState.getState().query).toStrictEqual({
-      esql: 'FROM the-data-view-title | LIMIT 10',
+      esql: 'FROM the-data-view-title | WHERE KQL("""foo: \'bar\'""") | LIMIT 10',
     });
     expect(state.globalState?.get?.()?.filters).toStrictEqual([]);
     expect(state.appState.getState().filters).toStrictEqual([]);

src/platform/plugins/shared/discover/public/application/main/state_management/discover_state.ts

@@ -25,7 +25,13 @@ import type { SavedSearch } from '@kbn/saved-search-plugin/public';
 import { v4 as uuidv4 } from 'uuid';
 import { merge } from 'rxjs';
 import { getInitialESQLQuery } from '@kbn/esql-utils';
-import { AggregateQuery, isOfAggregateQueryType, Query, TimeRange } from '@kbn/es-query';
+import {
+  AggregateQuery,
+  isOfAggregateQueryType,
+  isOfQueryType,
+  Query,
+  TimeRange,
+} from '@kbn/es-query';
 import { isFunction } from 'lodash';
 import { loadSavedSearch as loadSavedSearchFn } from './utils/load_saved_search';
 import { restoreStateFromSavedSearch } from '../../../services/saved_searches/restore_from_saved_search';
@@ -386,7 +392,10 @@ export function getDiscoverStateContainer({
   };
 
   const transitionFromDataViewToESQL = (dataView: DataView) => {
-    const queryString = getInitialESQLQuery(dataView);
+    const appState = appStateContainer.get();
+    const { query } = appState;
+    const filterQuery = query && isOfQueryType(query) ? query : undefined;
+    const queryString = getInitialESQLQuery(dataView, filterQuery);
 
     appStateContainer.update({
       query: { esql: queryString },