fix: app should only have one instance (#99)

## Motivation

<!-- List motivation and changes here -->

## Issues closed

<!-- List closed issues here -->

src/electron/background.ts

@@ -1,5 +1,6 @@
 import { app } from "electron";
 
+import { isTest } from "#/flags";
 import { main } from "@/main";
 import logger from "@/services/logger";
 import { watchStores } from "@/stores/watchers";
@@ -56,21 +57,34 @@ import "@/ipc/vector-store";
 // Import keys
 import "@/ipc/keys";
 
+// Obtain a lock to check if the app is locked (primary instance)
+// If false, we close the app, as we want to prevent multiple instances of our app
+// https://github.com/electron/electron/blob/v30.0.0-nightly.20240221/docs/api/app.md#apprequestsingleinstancelockadditionaldata
+const gotTheLock = app.requestSingleInstanceLock();
+
 let unsubscribe: (() => Promise<void>) | undefined;
-// Initialize the application by calling the main function.
-// Upon completion, log to the console indicating the application has started.
-main().then(() => {
-	logger.info("Application started successfully");
-	unsubscribe = watchStores();
-});
-
-// Listen for the 'window-all-closed' event on the Electron app object.
-// This event is emitted when all windows of the application have been closed.
-// In response, quit the application to free up resources, adhering to typical desktop application
-// behavior.
-app.on("window-all-closed", () => {
+
+if (gotTheLock || isTest) {
+	main().then(() => {
+		logger.info("Application started successfully");
+		unsubscribe = watchStores();
+	});
+
+	// Listen for the 'window-all-closed' event on the Electron app object.
+	// This event is emitted when all windows of the application have been closed.
+	// In response, quit the application to free up resources, adhering to typical desktop application
+	// behavior.
+	app.on("window-all-closed", () => {
+		app.quit();
+		if (unsubscribe) {
+			unsubscribe();
+		}
+	});
+} else {
+	// The app is locked, so we force quit the new instance
+	console.log("App is locked by another instance. Closing app");
 	app.quit();
 	if (unsubscribe) {
 		unsubscribe();
 	}
-});
+}

src/electron/future/main.ts

@@ -302,7 +302,6 @@ export async function main() {
 
 	logger.info(`main(): app is upToDate ${isUpToDate} and ready ${isReady}`);
 
-	// Remove the default application menu in production
 	if (isProduction) {
 		Menu.setApplicationMenu(null);
 
@@ -337,6 +336,17 @@ export async function main() {
 	logger.info(`main(): listened to :open`);
 
 	if (isUpToDate && isReady) {
+		app.on("second-instance", async () => {
+			apps.core ||= await createCoreWindow();
+
+			if (apps.core) {
+				if (apps.core.isMinimized()) {
+					apps.core.restore();
+				}
+
+				apps.core.focus();
+			}
+		});
 		// Start the vector store and fill it with data
 		await initialize();
 		await reset();
@@ -353,6 +363,16 @@ export async function main() {
 		// Create and show installer window
 		const installerWindow = await createInstallerWindow();
 
+		app.on("second-instance", async () => {
+			apps.core ||= await createCoreWindow();
+
+			if (installerWindow.isMinimized()) {
+				installerWindow.restore();
+			}
+
+			installerWindow.focus();
+		});
+
 		// When the installer is done we open the prompt window
 		ipcMain.on(buildKey([ID.APP], { suffix: ":ready" }), async () => {
 			await runStartup();

src/electron/future/utils/__tests__/path-helpers.test.ts

@@ -24,6 +24,7 @@ jest.mock("electron", () => ({
 
 jest.mock("#/flags", () => ({
 	isDevelopment: jest.requireActual("#/flags").isDevelopment,
+	isTest: jest.requireActual("#/flags").isTest,
 }));
 
 describe("Path Utilities", () => {
@@ -41,6 +42,7 @@ describe("Path Utilities", () => {
 	it("correctly sets resourcesDirectory in development mode", async () => {
 		jest.mock("#/flags", () => ({
 			isDevelopment: true,
+			isTest: true,
 		}));
 		const expectedDevelopmentPath = path.join(process.cwd(), "resources");
 		const { resourcesDirectory } = await import("../path-helpers");
@@ -50,6 +52,7 @@ describe("Path Utilities", () => {
 	it("correctly sets resourcesDirectory in production mode", async () => {
 		jest.mock("#/flags", () => ({
 			isDevelopment: false,
+			isTest: false,
 		}));
 
 		const { resourcesDirectory } = await import("../path-helpers");

src/electron/future/utils/path-helpers.ts

@@ -6,11 +6,12 @@ import path from "path";
 
 import { app } from "electron";
 
-import { isDevelopment } from "#/flags";
+import { isDevelopment, isTest } from "#/flags";
 
-export const resourcesDirectory = isDevelopment
-	? path.join(process.cwd(), "resources")
-	: path.join(app.getPath("exe"), "..", "resources", "app.asar.unpacked", "resources");
+export const resourcesDirectory =
+	isTest || isDevelopment
+		? path.join(process.cwd(), "resources")
+		: path.join(app.getPath("exe"), "..", "resources", "app.asar.unpacked", "resources");
 
 /**
  * Combines the resources directory path with additional subpaths.

src/shared/flags.ts

@@ -1,6 +1,7 @@
 export const isProduction = process.env.NODE_ENV === "production";
-export const isDevelopment =
+export const isTest =
 	process.env.TEST_ENV === "local" ||
 	process.env.TEST_ENV === "test" ||
-	process.env.NODE_ENV === "development" ||
 	process.env.NODE_ENV === "test";
+
+export const isDevelopment = process.env.NODE_ENV === "development";