[ES|QL] Separate ROW and SHOW autocomplete routines (#210934)

## Summary

Part of https://github.com/elastic/kibana/issues/195418

Gives `ROW` and `SHOW` autocomplete logic its own home 🏡

### Checklist

- [x] [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

### Identify risks

- [ ] As with any refactor, there's a possibility this will introduce a
regression in the behavior of FROM. However, all automated tests are
passing and I have tested the behavior manually and can detect no
regression.

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: Stratoula Kalafateli <efstratia.kalafateli@elastic.co>

src/platform/packages/shared/kbn-esql-validation-autocomplete/src/autocomplete/__tests__/autocomplete.command.row.test.ts

@@ -0,0 +1,38 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { getNewVariableSuggestion } from '../factories';
+import { attachTriggerCommand, getFunctionSignaturesByReturnType, setup } from './helpers';
+
+describe('autocomplete.suggest', () => {
+  describe('ROW column1 = value1[, ..., columnN = valueN]', () => {
+    const functions = getFunctionSignaturesByReturnType('row', 'any', { scalar: true });
+    it('suggests functions and an assignment for new expressions', async () => {
+      const { assertSuggestions } = await setup();
+      const expectedSuggestions = [getNewVariableSuggestion('var0'), ...functions];
+
+      await assertSuggestions('ROW /', expectedSuggestions);
+      await assertSuggestions('ROW foo = "bar", /', expectedSuggestions);
+    });
+
+    it('suggests only functions after an assignment', async () => {
+      const { assertSuggestions } = await setup();
+      await assertSuggestions('ROW var0 = /', functions);
+    });
+
+    it('suggests a comma and a pipe after a complete expression', async () => {
+      const { assertSuggestions } = await setup();
+      const expected = [', ', '| '].map(attachTriggerCommand);
+
+      await assertSuggestions('ROW var0 = 23 /', expected);
+      await assertSuggestions('ROW ABS(23) /', expected);
+      await assertSuggestions('ROW ABS(23), var0=234 /', expected);
+    });
+  });
+});

src/platform/packages/shared/kbn-esql-validation-autocomplete/src/autocomplete/__tests__/autocomplete.command.show.test.ts

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { attachTriggerCommand, setup } from './helpers';
+
+describe('autocomplete.suggest', () => {
+  describe('SHOW INFO', () => {
+    it('suggests INFO', async () => {
+      const { assertSuggestions } = await setup();
+
+      await assertSuggestions('SHOW /', ['INFO']);
+    });
+
+    it('suggests pipe after INFO', async () => {
+      const { assertSuggestions } = await setup();
+
+      await assertSuggestions('SHOW INFO /', [attachTriggerCommand('| ')]);
+      await assertSuggestions('SHOW INFO\t/', [attachTriggerCommand('| ')]);
+      await assertSuggestions('SHOW info /', [attachTriggerCommand('| ')]);
+    });
+
+    it('suggests nothing after a random word', async () => {
+      const { assertSuggestions } = await setup();
+
+      await assertSuggestions('SHOW lolz /', []);
+      await assertSuggestions('SHOW inof /', []);
+    });
+  });
+});

src/platform/packages/shared/kbn-esql-validation-autocomplete/src/autocomplete/commands/row/index.ts

@@ -0,0 +1,45 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { isRestartingExpression } from '../../../shared/helpers';
+import { CommandSuggestParams } from '../../../definitions/types';
+
+import type { SuggestionRawDefinition } from '../../types';
+import {
+  TRIGGER_SUGGESTION_COMMAND,
+  getFunctionSuggestions,
+  getNewVariableSuggestion,
+} from '../../factories';
+import { commaCompleteItem, pipeCompleteItem } from '../../complete_items';
+
+export async function suggest({
+  getSuggestedVariableName,
+  command,
+  innerText,
+}: CommandSuggestParams<'row'>): Promise<SuggestionRawDefinition[]> {
+  // ROW var0 = /
+  if (/=\s*$/.test(innerText)) {
+    return getFunctionSuggestions({ command: 'row' });
+  }
+
+  // ROW var0 = 23 /
+  else if (command.args.length > 0 && !isRestartingExpression(innerText)) {
+    return [
+      { ...pipeCompleteItem, command: TRIGGER_SUGGESTION_COMMAND },
+      { ...commaCompleteItem, text: ', ', command: TRIGGER_SUGGESTION_COMMAND },
+    ];
+  }
+
+  // ROW /
+  // ROW foo = "bar", /
+  return [
+    getNewVariableSuggestion(getSuggestedVariableName()),
+    ...getFunctionSuggestions({ command: 'row' }),
+  ];
+}

src/platform/packages/shared/kbn-esql-validation-autocomplete/src/autocomplete/commands/show/index.ts

@@ -0,0 +1,38 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { i18n } from '@kbn/i18n';
+import { CommandSuggestParams } from '../../../definitions/types';
+import type { SuggestionRawDefinition } from '../../types';
+import { pipeCompleteItem } from '../../complete_items';
+import { TRIGGER_SUGGESTION_COMMAND } from '../../factories';
+
+export async function suggest({
+  innerText,
+}: CommandSuggestParams<'show'>): Promise<SuggestionRawDefinition[]> {
+  // SHOW INFO /
+  if (/INFO\s+$/i.test(innerText)) {
+    return [{ ...pipeCompleteItem, command: TRIGGER_SUGGESTION_COMMAND }];
+  }
+  // SHOW INSOF /
+  else if (/SHOW\s+\S+\s+$/i.test(innerText)) {
+    return [];
+  }
+  // SHOW /
+  return [
+    {
+      text: 'INFO',
+      detail: i18n.translate('kbn-esql-validation-autocomplete.esql.show.info.detail', {
+        defaultMessage: 'Get information about the Elasticsearch cluster.',
+      }),
+      kind: 'Method',
+      label: 'INFO',
+    },
+  ];
+}

src/platform/packages/shared/kbn-esql-validation-autocomplete/src/definitions/commands.ts

@@ -44,6 +44,8 @@ import { suggest as suggestForStats } from '../autocomplete/commands/stats';
 import { suggest as suggestForWhere } from '../autocomplete/commands/where';
 import { suggest as suggestForJoin } from '../autocomplete/commands/join';
 import { suggest as suggestForFrom } from '../autocomplete/commands/from';
+import { suggest as suggestForRow } from '../autocomplete/commands/row';
+import { suggest as suggestForShow } from '../autocomplete/commands/show';
 
 const statsValidator = (command: ESQLCommand) => {
   const messages: ESQLMessage[] = [];
@@ -191,12 +193,13 @@ export const commandDefinitions: Array<CommandDefinition<any>> = [
       defaultMessage:
         'Produces a row with one or more columns with values that you specify. This can be useful for testing.',
     }),
-    examples: ['row a=1', 'row a=1, b=2'],
+    examples: ['ROW a=1', 'ROW a=1, b=2'],
     signature: {
       multipleParams: true,
       // syntax check already validates part of this
       params: [{ name: 'assignment', type: 'any' }],
     },
+    suggest: suggestForRow,
     options: [],
     modes: [],
   },
@@ -220,13 +223,14 @@ export const commandDefinitions: Array<CommandDefinition<any>> = [
     description: i18n.translate('kbn-esql-validation-autocomplete.esql.definitions.showDoc', {
       defaultMessage: 'Returns information about the deployment and its capabilities',
     }),
-    examples: ['show info'],
+    examples: ['SHOW INFO'],
     options: [],
     modes: [],
     signature: {
       multipleParams: false,
       params: [{ name: 'functions', type: 'function' }],
     },
+    suggest: suggestForShow,
   },
   {
     name: 'metrics',