Increment azure function name when using create azure func from table (#17236)

* increment azure function name

* add js docs

localization/xliff/enu/constants/localizedConstants.enu.xlf

@@ -566,6 +566,9 @@
         <trans-unit id="selectAzureFunctionProjFolder">
             <source xml:lang="en">Select folder for the Azure Function project</source>
         </trans-unit>
+         <trans-unit id="nameMustNotBeEmpty">
+            <source xml:lang="en">Name must not be empty</source>
+        </trans-unit>
     </body>
   </file>
 </xliff>

src/azureFunction/azureFunctionUtils.ts

@@ -32,7 +32,7 @@ export interface ILocalSettingsJson {
  * @returns settings in local.settings.json. If no settings are found, returns default "empty" settings
  */
 export async function getLocalSettingsJson(localSettingsPath: string): Promise<ILocalSettingsJson> {
-	if (await fs.existsSync(localSettingsPath)) {
+	if (fs.existsSync(localSettingsPath)) {
 		const data: string = (fs.readFileSync(localSettingsPath)).toString();
 		try {
 			return JSON.parse(data);

src/services/azureFunctionsService.ts

@@ -6,10 +6,11 @@
 import SqlToolsServiceClient from '../languageservice/serviceclient';
 import * as vscode from 'vscode';
 import * as mssql from 'vscode-mssql';
+import * as path from 'path';
 import * as azureFunctionsContracts from '../models/contracts/azureFunctions/azureFunctionsContracts';
 import * as azureFunctionUtils from '../azureFunction/azureFunctionUtils';
 import * as constants from '../constants/constants';
-import { generateQuotedFullName } from '../utils/utils';
+import { generateQuotedFullName, getUniqueFileName } from '../utils/utils';
 import * as LocalizedConstants from '../constants/localizedConstants';
 
 export const hostFileName: string = 'host.json';
@@ -84,10 +85,12 @@ export class AzureFunctionsService implements mssql.IAzureFunctionsService {
 		const newFilePromise = azureFunctionUtils.waitForNewFunctionFile(projectFile);
 
 		// get function name from user
+		let uniqueFunctionName = await getUniqueFileName(path.dirname(projectFile), table);
 		const functionName = await vscode.window.showInputBox({
 			title: LocalizedConstants.functionNameTitle,
-			value: table,
-			ignoreFocusOut: true
+			value: uniqueFunctionName,
+			ignoreFocusOut: true,
+			validateInput: input => input ? undefined : LocalizedConstants.nameMustNotBeEmpty
 		});
 		if (!functionName) {
 			return;

src/utils/utils.ts

@@ -4,6 +4,8 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as cp from 'child_process';
+import * as fs from 'fs';
+import * as path from 'path';
 import { escapeClosingBrackets } from '../models/utils';
 
 export async function executeCommand(command: string, cwd?: string): Promise<string> {
@@ -31,3 +33,27 @@ export async function executeCommand(command: string, cwd?: string): Promise<str
 export function generateQuotedFullName(schema: string, objectName: string): string {
 	return `[${escapeClosingBrackets(schema)}].[${escapeClosingBrackets(objectName)}]`;
 }
+
+
+/**
+ * Gets a unique file name
+ * Increment the file name by adding 1 to function name if the file already exists
+ * Undefined if the filename suffix count becomes greater than 1024
+ * @param folderPath selected project folder path
+ * @param fileName base filename to use
+ * @returns a promise with the unique file name, or undefined
+ */
+export async function getUniqueFileName(folderPath: string, fileName: string): Promise<string | undefined> {
+	let count: number = 0;
+	const maxCount: number = 1024;
+	let uniqueFileName = fileName;
+
+	while (count < maxCount) {
+		if (!fs.existsSync(path.join(folderPath, uniqueFileName + '.cs'))) {
+			return uniqueFileName;
+		}
+		count += 1;
+		uniqueFileName = fileName + count.toString();
+	}
+	return undefined;
+}